Experimental study on two-phase flow natural circulation in a core catcher cooling channel for EU-APR1400 using air-water system

Energy Technology Data Exchange (ETDEWEB)

Song, Ki Won [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Nguyen, Thanh Hung [School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Ha, Kwang Soon; Kim, Hwan Yeol; Song, Jinho [Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Park, Hyun Sun [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Revankar, Shripad T., E-mail: shripad@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of)

2017-05-15

Highlights: • Two-phase flow regimes and transition behavior were observed in the coolant channel. • Test were conducted for natural circulation with air-water. • Data were obtained on flow regime, void fraction, flow rates and re-wetting time. • The data were related to a cooling capability of core catcher system. - Abstract: Ex-vessel core catcher cooling system driven by natural circulation is designed using a full scaled air-water system. A transparent half symmetric section of a core catcher coolant channel of a pressurized water reactor was designed with instrumentations for local void fraction measurement and flow visualization. Two designs of air-water top separator water tanks are studied including one with modified ‘super-step’ design which prevents gas entrainment into down-comer. In the experiment air flow rates are set corresponding to steam generation rate for given corium decay power. Measurements of natural circulation flow rate, spatial local void fraction distribution and re-wetting time near the top wall are carried out for various air flow rates which simulate boiling-induced vapor generation. Since heat transfer and critical heat flux are strongly dependent on the water mass flow rate and development of two-phase flow on the heated wall, knowledge of two-phase flow characteristics in the coolant channel is essential. Results on flow visualization showing two phase flow structure specifically near the high void accumulation regions, local void profiles, rewetting time, and natural circulation flow rate are presented for various air flow rates that simulate corium power levels. The data are useful in assessing the cooling capability of and safety of the core catcher system.

Secondary flows in the cooling channels of the high-performance light-water reactor

Energy Technology Data Exchange (ETDEWEB)

Laurien, E.; Wintterle, Th. [Stuttgart Univ., Institute for Nuclear Technolgy and Energy Systems (IKE) (Germany)

2007-07-01

The new design of a High-Performance Light-Water Reactor (HPLWR) involves a three-pass core with an evaporator region, where the compressed water is heated above the pseudo-critical temperature, and two superheater regions. Due to the strong dependency of the supercritical water density on the temperature significant mass transfer between neighboring cooling channels is expected if the temperature is unevenly distributed across the fuel element. An inter-channel flow is then superimposed to the secondary flow vortices induced by the non-isotropy of turbulence. In order to gain insight into the resulting flow patterns as well as into temperature and density distributions within the various subchannels of the fuel element CFD (Computational Fluid Dynamics) calculations for the 1/8 fuel element are performed. For simplicity adiabatic boundary conditions at the moderator box and the fuel element box are assumed. Our investigation confirms earlier results obtained by subchannel analysis that the axial mass flux is significantly reduced in the corner subchannel of this fuel element resulting in a net mass flux towards the neighboring subchannels. Our results provide a first estimation of the magnitude of the secondary flows in the pseudo-critical region of a supercritical light-water reactor. Furthermore, it is demonstrated that CFD is an efficient tool for investigations of flow patterns within nuclear reactor fuel elements. (authors)

Cooling-water amounts, temperature, and the environment

International Nuclear Information System (INIS)

Koops, F.B.J.; Donze, M.; Hadderingh, R.H.

1979-01-01

The release of heat from power plants into a water can take place with relative small quantities of cooling water, highly warmed up accordingly, or with large quantities of cooling water slightly warmed up. The utilization of cooling water is bound to certain guidelines established by the authorities. With the intention to protect the environment, the admissable temperatures and warming-up have been strictly limited by the authorities. In the Netherlands, we have presently temporary cooling water guidelines which allow a max. temperature of the cooling water in the cooling cycle of 30 0 C and a maximum admissible temperature rise in the condenser between 7 0 C during summer and 15 0 C during winter. It has also been determined in these requirements how much cooling water at least has to be used to discharge a specified quantity of heat. Plankton, spawn and young fish are dragged with the cooling water. Harm to these organisms can be caused mechanically by pumps, sieves and the condenser or they can be harmed by the temperature rise in the condenser. Investigations showed that mechanical harm to spawn and young fish in the cooling water flow should not be ignored, and that detectable harm to plankton organisms takes place only at water temperatures above 32 0 C. The cooling water consumption can therefore be optimised as follows: The solution of a greater temperature increase and a slightly higher value for the temperature maximum can reduce the cooling water quantity. This reduction of the cooling water quantity reduces the destruction of the fish quantity, which gets into the cooling water system, especially during the summer. If the temperature rise and the temperature itself are not selected too high, the destruction of fish may be reduced without causing serious damage to the plankton. (orig.) [de

Device for recirculation cooling of cooling water by natural or forced chaft

Energy Technology Data Exchange (ETDEWEB)

Ruehl, H; Honekamp, H; Katzmann, A

1975-10-23

The invention is concerned with a device for recirculation cooling of cooling water by natural or forced draft. Through a cascading system mounted on supporting columns at a vertical distance to ground level, cooling air is flowing in cross- or counterflow to the cooling water freely falling from the cascading system. The cooling water collecting zone below the cascading system has an absorption floor arranged nearly horizontal and/or inclined, with a cam-type profile on its upperside, which is bounded on its circumference by at least one cooling water release channel provided below its level and/or which is divided in the sense of a surface subdivision. By these means, a reduction of the amount of material required for the supporting columns and an increase of the stability of the columns is to be achieved. Furthermore, the deposition of mud is to be avoided as for as possible, and noise generation during operation is to be reduced considerably. For this purpose, the absorption floor may be made of material sound insulating and/or may be coated with such a material.

Increasing photovoltaic panel power through water cooling technique

Directory of Open Access Journals (Sweden)

Calebe Abrenhosa Matias

2017-02-01

Full Text Available This paper presents the development of a cooling apparatus using water in a commercial photovoltaic panel in order to analyze the increased efficiency through decreased operating temperature. The system enables the application of reuse water flow, at ambient temperature, on the front surface of PV panel and is composed of an inclined plane support, a perforated aluminum profile and a water gutter. A luminaire was specially developed to simulate the solar radiation over the module under test in a closed room, free from the influence of external climatic conditions, to carry out the repetition of the experiment in controlled situations. The panel was submitted to different rates of water flow. The best water flow rate was of 0.6 L/min and net energy of 77.41Wh. Gain of 22.69% compared to the panel without the cooling system.

An improved water cooled nuclear reactor and pressuriser assembly

International Nuclear Information System (INIS)

Gardner, F.J.; Strong, R.

1991-01-01

A water cooled nuclear reactor is described which comprises a reactor core, a primary water coolant circuit and a pressuriser arranged as an integral unit in a pressure vessel. The pressure vessel is divided into an upper and a lower chamber by a casing. The reactor core and primary water coolant circuit are arranged in the lower chamber and the pressuriser is arranged in the upper chamber. A plurality of spray pipes interconnect a steam space of the pressuriser with the downcomer of the primary water coolant circuit below a heat exchanger. A plurality of surge ports interconnect a water space of the pressuriser with the primary water coolant circuit. The surge ports have hydraulic diodes so that there is a low flow resistance for water from the water space of the pressuriser to the primary water coolant circuit and high flow resistance in the opposite direction. The spray pipes provide a desuperheating spray of cooled water into the pressuriser during positive volume surges of the primary water coolant. The pressuriser arrangement may also be applied to integral water cooled reactors with separate pressurisers and to dispersed pressurised water reactors. The surge ports also allow water to flow by gravity to the core in an emergency. (author)

3-Dimensional numerical study of cooling performance of a heat sink with air-water flow through mini-channel

Science.gov (United States)

Majumder, Sambit; Majumder, Abhik; Bhaumik, Swapan

2016-07-01

The present microelectronics market demands devices with high power dissipation capabilities having enhanced cooling per unit area. The drive for miniaturizing the devices to even micro level dimensions is shooting up the applied heat flux on such devices, resulting in complexity in heat transfer and cooling management. In this paper, a method of CPU processor cooling is introduced where active and passive cooling techniques are incorporated simultaneously. A heat sink consisting of fins is designed, where water flows internally through the mini-channel fins and air flows externally. Three dimensional numerical simulations are performed for large set of Reynolds number in laminar region using finite volume method for both developing flows. The dimensions of mini-channel fins are varied for several aspect ratios such as 1, 1.33, 2 and 4. Constant temperature (T) boundary condition is applied at heat sink base. Channel fluid temperature, pressure drop are analyzed to obtain best cooling option in the present study. It has been observed that as the aspect ratio of the channel decreases Nusselt number decreases while pressure drop increases. However, Nusselt number increases with increase in Reynolds number.

Coupling model and solving approach for performance evaluation of natural draft counter-flow wet cooling towers

Directory of Open Access Journals (Sweden)

Wang Wei

2016-01-01

Full Text Available When searching for the optimum condenser cooling water flow in a thermal power plant with natural draft cooling towers, it is essential to evaluate the outlet water temperature of cooling towers when the cooling water flow and inlet water temperature change. However, the air outlet temperature and tower draft or inlet air velocity are strongly coupled for natural draft cooling towers. Traditional methods, such as trial and error method, graphic method and iterative methods are not simple and efficient enough to be used for plant practice. In this paper, we combine Merkel equation with draft equation, and develop the coupled description for performance evaluation of natural draft cooling towers. This model contains two inputs: the cooling water flow, the inlet cooling water temperature and two outputs: the outlet water temperature, the inlet air velocity, equivalent to tower draft. In this model, we furthermore put forward a soft-sensing algorithm to calculate the total drag coefficient instead of empirical correlations. Finally, we design an iterative approach to solve this coupling model, and illustrate three cases to prove that the coupling model and solving approach proposed in our paper are effective for cooling tower performance evaluation.

Sea water take-up facility for cooling reactor auxiliary

International Nuclear Information System (INIS)

Numata, Noriko; Mizutani, Akira; Hirako, Shizuka; Uchiyama, Yuichi; Oda, Atsushi.

1997-01-01

The present invention provides an improvement of a cooling sea water take-up facility for cooling auxiliary equipments of nuclear power plant. Namely, an existent sea water take-up facility for cooling reactor auxiliary equipments has at least two circulation water systems and three independent sea water systems for cooling reactor auxiliary equipments. In this case, a communication water channel is disposed, which connects the three independent sea water systems for cooling reactor auxiliary equipments mutually by an opening/closing operation of a flow channel partitioning device. With such a constitution, even when any combination of two systems among the three circulation water systems is in inspection at the same time, one system for cooling the reactor auxiliary equipments can be kept operated, and one system is kept in a stand-by state by the communication water channel upon periodical inspection of water take-up facility for cooling the auxiliary equipments. As a result, the sea water take-up facility for cooling auxiliary equipments of the present invention have operation efficiency higher than that of a conventional case while keeping the function and safety at the same level as in the conventional case. (I.S.)

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water.

Science.gov (United States)

Chien, S H; Hsieh, M K; Li, H; Monnell, J; Dzombak, D; Vidic, R

2012-02-01

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ∕h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m∕s), and air mass velocity (3660 kg∕h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

Performance Evaluation of a Mechanical Draft Cross Flow Cooling Towers Employed in a Subtropical Region

Science.gov (United States)

Muthukumar, Palanisamy; Naik, Bukke Kiran; Goswami, Amarendra

2018-02-01

Mechanical draft cross flow cooling towers are generally used in a large-scale water cooled condenser based air-conditioning plants for removing heat from warm water which comes out from the condensing unit. During this process considerable amount of water in the form of drift (droplets) and evaporation is carried away along with the circulated air. In this paper, the performance evaluation of a standard cross flow induced draft cooling tower in terms of water loss, range, approach and cooling tower efficiency are presented. Extensive experimental studies have been carried out in three cooling towers employed in a water cooled condenser based 1200 TR A/C plant over a period of time. Daily variation of average water loss and cooling tower performance parameters have been reported for some selected days. The reported average water loss from three cooling towers is 4080 l/h and the estimated average water loss per TR per h is about 3.1 l at an average relative humidity (RH) of 83%. The water loss during peak hours (2 pm) is about 3.4 l/h-TR corresponding to 88% of RH and the corresponding efficiency of cooling towers varied between 25% and 45%.

Mathematical model and calculation of water-cooling efficiency in a film-filled cooling tower

Science.gov (United States)

Laptev, A. G.; Lapteva, E. A.

2016-10-01

Different approaches to simulation of momentum, mass, and energy transfer in packed beds are considered. The mathematical model of heat and mass transfer in a wetted packed bed for turbulent gas flow and laminar wave counter flow of the fluid film in sprinkler units of a water-cooling tower is presented. The packed bed is represented as the set of equivalent channels with correction to twisting. The idea put forward by P. Kapitsa on representation of waves on the interphase film surface as elements of the surface roughness in interaction with the gas flow is used. The temperature and moisture content profiles are found from the solution of differential equations of heat and mass transfer written for the equivalent channel with the volume heat and mass source. The equations for calculation of the average coefficients of heat emission and mass exchange in regular and irregular beds with different contact elements, as well as the expression for calculation of the average turbulent exchange coefficient are presented. The given formulas determine these coefficients for the known hydraulic resistance of the packed bed element. The results of solution of the system of equations are presented, and the water temperature profiles are shown for different sprinkler units in industrial water-cooling towers. The comparison with experimental data on thermal efficiency of the cooling tower is made; this allows one to determine the temperature of the cooled water at the output. The technical solutions on increasing the cooling tower performance by equalization of the air velocity profile at the input and creation of an additional phase contact region using irregular elements "Inzhekhim" are considered.

Study on the Effect of water Injection Momentum on the Cooling Effect of Rocket Engine Exhaust Plume

Science.gov (United States)

Yang, Kan; Qiang, Yanhui; Zhong, Chenghang; Yu, Shaozhen

2017-10-01

For the study of water injection momentum factors impact on flow field of the rocket engine tail flame, the numerical computation model of gas-liquid two phase flow in the coupling of high temperature and high speed gas flow and low temperature liquid water is established. The accuracy and reliability of the numerical model are verified by experiments. Based on the numerical model, the relationship between the flow rate and the cooling effect is analyzed by changing the water injection momentum of the water spray pipes. And the effective mathematical expression is obtained. What’s more, by changing the number of the water spray and using small flow water injection, the cooling effect is analyzed to check the application range of the mathematical expressions. The results show that: the impact and erosion of the gas flow field could be reduced greatly by water injection, and there are two parts in the gas flow field, which are the slow cooling area and the fast cooling area. In the fast cooling area, the influence of the water flow momentum and nozzle quantity on the cooling effect can be expressed by mathematical functions without causing bifurcation flow for the mainstream gas. The conclusion provides a theoretical reference for the engineering application.

The influence and analysis of natural crosswind on cooling characteristics of the high level water collecting natural draft wet cooling tower

Science.gov (United States)

Ma, Libin; Ren, Jianxing

2018-01-01

Large capacity and super large capacity thermal power is becoming the main force of energy and power industry in our country. The performance of cooling tower is related to the water temperature of circulating water, which has an important influence on the efficiency of power plant. The natural draft counter flow wet cooling tower is the most widely used cooling tower type at present, and the high cooling tower is a new cooling tower based on the natural ventilation counter flow wet cooling tower. In this paper, for high cooling tower, the application background of high cooling tower is briefly explained, and then the structure principle of conventional cooling tower and high cooling tower are introduced, and the difference between them is simply compared. Then, the influence of crosswind on cooling performance of high cooling tower under different wind speeds is introduced in detail. Through analysis and research, wind speed, wind cooling had little impact on the performance of high cooling tower; wind velocity, wind will destroy the tower inside and outside air flow, reducing the cooling performance of high cooling tower; Wind speed, high cooling performance of cooling tower has increased, but still lower than the wind speed.

Instrumentation for NBI SST-1 cooling water system

International Nuclear Information System (INIS)

Qureshi, Karishma; Patel, Paresh; Jana, M.R.

2015-01-01

Neutral Beam Injector (NBI) System is one of the heating systems for Steady state Superconducting Tokamak (SST-1). It is capable of generating a neutral hydrogen beam of power 0.5 MW at 30 kV. NBI system consists of following sub-systems: Ion source, Neutralizer, Deflection Magnet and Magnet Liner (ML), Ion Dump (ID), V-Target (VT), Pre Duct Scraper (PDS), Beam Transmission Duct (BTD) and Shine Through (ST). For better heat removal management purpose all the above sub-systems shall be equipped with Heat Transfer Elements (THE). During beam operation these sub-systems gets heated due to the received heat load which requires to be removed by efficient supplying water. The cooling water system along with the other systems (External Vacuum System, Gas Feed System, Cryogenics System, etc.) will be controlled by NBI Programmable Logic Control (PLC). In this paper instrumentation and its related design for cooling water system is discussed. The work involves flow control valves, transmitters (pressure, temperature and water flow), pH and conductivity meter signals and its interface with the NBI PLC. All the analog input, analog output, digital input and digital output signals from the cooling water system will be isolated and then fed to the NBI PLC. Graphical Users Interface (GUI) needed in the Wonderware SCADA for the cooling water system shall also be discussed. (author)

40 CFR 63.1086 - How must I monitor for leaks to cooling water?

Science.gov (United States)

2010-07-01

... monitor for leaks to cooling water? You must monitor for leaks to cooling water by monitoring each heat... system so that the cooling water flow rate is 51,031 liters per minute or less so that a leak of 3.06 kg... detected a leak. (b) Individual heat exchangers. Monitor the cooling water at the entrance and exit of each...

Corrosion induced clogging and plugging in water-cooled generator cooling circuit

International Nuclear Information System (INIS)

Park, B.G.; Hwang, I.S.; Rhee, I.H.; Kim, K.T.; Chung, H.S.

2002-01-01

Water-cooled electrical generators have been experienced corrosion-related problems that are restriction of flow through water strainers caused by collection of excessive amounts of copper corrosion products (''clogging''), and restriction of flow through the copper strands in the stator bars caused by growth or deposition of corrosion products on the walls of the hollow strands (''plugging''). These phenomena result in unscheduled shutdowns that would be a major concern because of the associated loss in generating capacity. Water-cooled generators are operated in one of two modes. They are cooled either with aerated water (dissolved oxygen >2 ppm) or with deaerated water (dissolved oxygen <50 ppb). Both modes maintain corrosion rates at satisfactorily low levels as long as the correct oxygen concentrations are maintained. However, it is generally believed that very much higher copper corrosion rates result at the intermediate oxygen concentrations of 100-1000 ppb. Clogging and plugging are thought to be associated with these intermediate concentrations, and many operators have suggested that the period of change from high-to-low or from low-to-high oxygen concentration is particularly damaging. In order to understand the detailed mechanism(s) of the copper oxide formation, release and deposition and to identify susceptible conditions in the domain of operating variables, a large-scale experiments are conducted using six hollow strands of full length connected with physico-chemically scaled generator cooling water circuit. To ensure a close simulation of thermal-hydraulic conditions in a generator stator, strands of the loop will be ohmically heated using AC power supply. Experiments is conducted to cover oxygen excursions in both high dissolved oxygen and low dissolved oxygen conditions that correspond to two representative operating condition at fields. A thermal upset condition is also simulated to examine the impact of thermal stress. During experiments

Open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water

International Nuclear Information System (INIS)

Hou Shaobo; Li Huacong; Zhang Hefei

2007-01-01

This paper presents an open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6 o C. Its refrigeration depends mainly on both air and vapor, more efficient than a conventional air cycle, and the use of turbo-machinery makes this possible. This system could use the cool in the cool water, which could not be used to cool air directly. Also, the heat rejected from this system could be used to heat cool water to 33-40 o C. The sensitivity analysis of COP to η c and η t and the simulated results T 4 , T 7 , T 8 , q 1 , q 2 and W m of the cycle are given. The simulations show that the COP of this system depends mainly on T 7 , η c and η t and varies with T 3 or T wet and that this cycle is feasible in some regions, although the COP is sensitive to the efficiencies of the axial compressor and turbine. The optimum pressure ratio in this system could be lower, and this results in a fewer number of stages of the axial compressor. Adjusting the rotation speed of the axial compressor can easily control the pressure ratio, mass flow rate and the refrigerating capacity. The adoption of this cycle will make the air conditioned room more comfortable and reduce the initial investment cost because of the obtained very low temperature air. Humid air is a perfect working fluid for central air conditioning and no cost to the user. The system is more efficient because of using cool water to cool the air before the turbine. In addition, pinch technology is a good method to analyze the wet air heat exchange with water

Cooling water conditioning and quality control for tokamaks

International Nuclear Information System (INIS)

Gootgeld, A.M.

1995-01-01

Designers and operators of Tokamaks and all associated water cooled, peripheral equipment, are faced with the task of providing and maintaining closed-loop, low conductivity, low impurity, cooling water systems. The primary reason for supplying low conductivity water to the DIII-D vacuum vessel coils, power supplies and auxiliary heating components is to assure, along with the use of a non-conducting break in the supply piping, sufficient electrical resistance and thus an acceptable current-leakage path to ground at operating voltage potentials. As important, good quality cooling water significantly reduces the likelihood of scaling and fouling of flow passages and heat transfer surfaces. Dissolved oxygen gas removal is also required in one major DIII-D cooling water system to minimize corrosion in the ion sources of the neutral beam injectors. Currently, the combined pumping capacity of the high quality cooling water systems at DIII-D is ∼5,000 gpm. Another area that receives close attention at DIII-D is the chemical treatment of the water used in the cooling towers. This paper discusses the DIII-D water quality requirements, the means used to obtain the necessary quality and the instrumentation used for control and monitoring. Costs to mechanically and chemically condition and maintain water quality are discussed as well as the various aspects of complying with government standards and regulations

Theoretical and experimental study of a cross-flow induced-draft cooling tower

Directory of Open Access Journals (Sweden)

Abo Elazm Mahmoud Mohamed

2009-01-01

Full Text Available The main objective of this study is to find a proper solution for the cross-flow water cooling tower problem, also to find an empirical correlation's controlling heat and mass transfer coefficients as functions of inlet parameters to the tower. This is achieved by constructing an experimental rig and a computer program. The computer simulation solves the problem numerically. The apparatus used in this study comprises a cross-flow cooling tower. From the results obtained, the 'characteristic curve' of cross-flow cooling towers was constructed. This curve is very helpful for designers in order to find the actual value of the number of transfer units, if the values of inlet water temperature or inlet air wet bulb temperature are changed. Also an empirical correlation was conducted to obtain the required number of transfer units of the tower in hot water operation. Another correlation was found to obtain the effectiveness in the wet bulb operation.

Eocene cooling linked to early flow across the Tasmanian Gateway.

Science.gov (United States)

Bijl, Peter K; Bendle, James A P; Bohaty, Steven M; Pross, Jörg; Schouten, Stefan; Tauxe, Lisa; Stickley, Catherine E; McKay, Robert M; Röhl, Ursula; Olney, Matthew; Sluijs, Appy; Escutia, Carlota; Brinkhuis, Henk

2013-06-11

The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52-50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica from 34 Ma onward. Whereas early studies attributed the Eocene transition from greenhouse to icehouse climates to the tectonic opening of Southern Ocean gateways, more recent investigations invoked a dominant role of declining atmospheric greenhouse gas concentrations (e.g., CO2). However, the scarcity of field data has prevented empirical evaluation of these hypotheses. We present marine microfossil and organic geochemical records spanning the early-to-middle Eocene transition from the Wilkes Land Margin, East Antarctica. Dinoflagellate biogeography and sea surface temperature paleothermometry reveal that the earliest throughflow of a westbound Antarctic Counter Current began ~49-50 Ma through a southern opening of the Tasmanian Gateway. This early opening occurs in conjunction with the simultaneous onset of regional surface water and continental cooling (2-4 °C), evidenced by biomarker- and pollen-based paleothermometry. We interpret that the westbound flowing current flow across the Tasmanian Gateway resulted in cooling of Antarctic surface waters and coasts, which was conveyed to global intermediate waters through invigorated deep convection in southern high latitudes. Although atmospheric CO2 forcing alone would provide a more uniform middle Eocene cooling, the opening of the Tasmanian Gateway better explains Southern Ocean surface water and global deep ocean cooling in the apparent absence of (sub-) equatorial cooling.

Determination of fan flow and water rate adjustment for off-design cooling tower tests

International Nuclear Information System (INIS)

Vance, J.M.

1984-02-01

The determination of the performance of a mechanical draft cooling tower requires that the air mass flow through the tower be known. Since this flow is not measured, it has been customary to use the manufacturer's design air flow and adjust it by the one-third power of the ratio of the design to test fan horsepower. The most nearly correct approximation of air flow through a tower can be obtained by incrementally moving through the tower from air inlet to outlet while calculating mass flows, energy balances, and pressure drops for each increment and then utilizing fan curves to determine volumetric and mass flows. This procedure would account for changes in air humidity and density through the tower, evaporation of water, effect of water rate on air pressure drop, and changes in fan characteristics. These type calculations may be within the capabilities of all in the near future, but for the interim, it is recommended that a more elementary approach be used which can be handled with a good calculator and without any proprietary data. This approach depends on certain assumptions which are acceptable if the tower test is conducted within CTI code requirements. The fan must be considered a constant suction volume blower for a given blade pitch. The total pressure at the fan, a function of volumetric flow and wet air density, must be assumed to be unaffected by other considerations, and the fan horsepower must be assumed to change only as volumetric flow and wet air density changes. Given these assumptions, along with design information normally provided with a tower, the determination of air flow through a tower in a test can be made from CTI test data. The air flow, and consequently the water rate adjustment and corrected water to air ratio, are derived and found to be direct functions of horsepower and density and an inverse function of wet air humidities

Simulation of Two-Phase Natural Circulation Loop for Core Cather Cooling Using Air Water

International Nuclear Information System (INIS)

Revankar, S. T.; Huang, S. F.; Song, K. W.; Rhee, B. W.; Park, R. J.; Song, J. H.

2012-01-01

A closed loop natural circulation system employs thermally induced density gradients in single phase or two-phase liquid form to induce circulation of the working fluid thereby obviating the need for any mechanical moving parts such as pumps and pump controls. This increases the reliability and safety of the cooling system and reduces installation, operation and maintenance costs. That is the reason natural circulation cooling has been considered in advanced reactor core cooling and in engineered safety systems. Natural circulation cooling has been proposed to remove reactor decay heat by external vessel cooling for in-vessel core retention during sever accident scenario. Recently in APR1400 reactor core catcher design natural circulation cooling is proposed to stabilize and cool the corium ejected from the reactor vessel following core melt and breach of reactor vessel. The natural circulation flow is similar to external vessel cooling where water flows through an inclined narrow gap below hot surface and is heated to produce boiling. The two-phase natural circulation enables cooling of the corium pool collected on core catcher. Due to importance of this problem this paper focuses simulation of the two-phase natural circulation through inclined gap using air-water system. Scaling criteria for air-water loop are derived that enable simulation of the flow regimes and natural circulation flow rates in such systems using air-water system

Experimental investigations on the contribution of the splash-zones in counter-flow cooling towers for water cooling

International Nuclear Information System (INIS)

Vladea, I.; Barbu, V.

1976-01-01

The relatively high cost of cooling tower packs has led to investigate the contribution of the splash-zones in counter-flow cooling towers, and thereby to determine whether the pack could not be reduced so far, as to be - under certain circumstance - completely eliminated. In this case, one would come to a pure splash cooling tower which would contain inside the equipment required for drop formation only. This problem was investigated experimentally, and it was found that the pack of such a cooling tower could not be eliminated without a reduction in tower effectiveness. (orig.) [de

Experimental Studies of NGNP Reactor Cavity Cooling System With Water

Energy Technology Data Exchange (ETDEWEB)

Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira

2013-01-16

This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.

Analysis of Two Phase Natural Circulation Flow in the Cooling Channel of the PECS

Energy Technology Data Exchange (ETDEWEB)

Park, R. J; Ha, K. S; Rhee, B. W; Kim, H. Y [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

Decay heat and sensible heat of the relocated and spread corium are removed by the natural circulation flow at the bottom and side wall of the core catcher and the top water cooling of the corium. The coolant in the inclined channel absorbs the decay heat and sensible heat transferred from the corium through the structure of the core catcher body and flows up to the pool as a two phase mixture. On the other hand, some of the pool water will flow into the inlet of the downcomer piping, and will flow into the inclined cooling channel of the core catcher by gravity. As shown in Fig. 1, the engineered cooling channel is designed to provide effective long-term cooling and stabilization of the corium mixture in the core catcher body while facilitating steam venting in the PECS. To maintain the integrity of the ex-vessel core catcher, however, it is necessary that the coolant be sufficiently circulated along the inclined cooling channel to avoid CHF (Critical Heat Flux) on the heating surface of the cooling channel. For this reason, a verification experiment on the cooling capability of the EU-APR1400 core catcher has been performed in the CE (Cooling Experiment)-PECS facility at KAERI. Preliminary simulations of two-phase natural circulation in the CE-PECS were performed to predict two-phase flow characteristics and to determine the natural circulation mass flow rate in the flow channel. In this study, simulations of two-phase natural circulation in a real core catcher of the PECS have been performed to determine the natural circulation mass flow rate in the flow channel using the RELAP5/MOD3 computer code.

Experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower

International Nuclear Information System (INIS)

Lemouari, M.; Boumaza, M.; Kaabi, A.

2011-01-01

Thermal and nuclear electric power plants as well as several industrial processes invariably discharge considerable energy to their surrounding by heat transfer. Although water drawn from a nearby river or lake can be employed to carry away this energy, cooling towers offer an excellent alternative particularly in locations where sufficient cooling water cannot be easily obtained from natural sources or where concern for the environment imposes some limits on the temperature at which cooling water can be returned to the surrounding. This paper concerns an experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower. The tower contains a 'VGA.' (Vertical Grid Apparatus) type packing which is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.15 m x 0.148 m. The present investigation is focused mainly on the effect of the air and water flow rates on the hydraulic characteristics of the cooling tower, for different inlet water temperatures. The two hydrodynamic operating regimes which were observed during the air/water contact operation within the tower, namely the Pellicular Regime (PR) and the Bubble and Dispersion Regime (BDR) have enabled to distinguish two different states of pressure drop characteristics. The first regime is characterized by low pressure drop values, while in the second regime, the pressure drop values are relatively much higher than those observed in the first one. The dependence between the pressure drop characteristics and the combined heat and mass transport (air-water) through the packing inside the cooling tower is also highlighted. The obtained results indicate that this type of tower possesses relatively good hydraulic characteristics. This leads to the saving of energy. -- Highlights: → Cooling towers are widely used to reject waste heat from thermal and nuclear

Alternative cooling water flow path for RHR heat exchanger and its effect on containment response during extended station blackout for Chinshan BWR-4 plant

Energy Technology Data Exchange (ETDEWEB)

Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw

2016-04-15

Highlights: • Motivating alternative RHR heat exchanger tube-side flow path and determining required capacity. • Calculate NSSS and containment response during 24-h SBO for Chinshan BWR-4 plant. • RETRAN and GOTHIC models are developed for NSSS and containment, respectively. • Safety relief valve blowdown flow and energy to drywell are generated by RETRAN. • Analyses are performed with and without reactor depressurization, respectively. - Abstract: The extended Station Blackout (SBO) of 24 h has been analyzed with respect to the containment response, in particular the suppression pool temperature response, for the Chinshan BWR-4 plant of MARK-I containment. The Chinshan plant, owned by Taiwan Power Company, has twin units with rated core thermal power of 1840 MW each. The analysis is aimed at determining the required alternative cooling water flow capacity for the residual heat removal (RHR) heat exchanger when its tube-side sea water cooling flow path is blocked, due to some reason such as earthquake or tsunami, and is switched to the alternative raw water source. Energy will be dissipated to the suppression pool through safety relief valves (SRVs) of the main steam lines during SBO. The RETRAN model is used to calculate the Nuclear Steam Supply System (NSSS) response and generate the SRV blowdown conditions, including SRV pressure, enthalpy, and mass flow rate. These conditions are then used as the time-dependent boundary conditions for the GOTHIC code to calculate the containment pressure and temperature response. The shaft seals of the two recirculation pumps are conservatively assumed to fail due to loss of seal cooling and a total leakage flow rate of 36 gpm to the drywell is included in the GOTHIC model. Based on the given SRV blowdown conditions, the GOTHIC containment calculation is performed several times, through the adjustment of the heat transfer rate of the RHR heat exchanger, until the criterion that the maximum suppression pool temperature

LOFA analyses for the water and helium cooled SEAFP reactors

International Nuclear Information System (INIS)

Sponton, L.; Sjoeberg, A.; Nordlinder, S.

2001-01-01

This study was performed in the frame of the European long-term fusion safety programme 1999 (SEAFP99). Loss of flow accidents (LOFA) have been studied for two cases, first for a helium cooled reactor with advanced dual-coolant (DUAL) blanket at 100% nominal power. The second case applies to a water-cooled reactor at 20% nominal power. Both transients were simulated with the code MELCOR 1.8.4. The results for the helium cooled reactor show that with a natural circulation flow of helium after the pump stops, the first wall temperature will stay below the temperature for excepted failure of the construction material. For the water cooled reactor, the results show that the pressurizer set point for its liquid volumetric inventory is reached before the plasma facing components attain a critical temperature. The pressurizer set point will induce a plasma shutdown

Cooled Water Production System,

Science.gov (United States)

The invention refers to the field of air conditioning and regards an apparatus for obtaining cooled water . The purpose of the invention is to develop...such a system for obtaining cooled water which would permit the maximum use of the cooling effect of the water -cooling tower.

Fluid Induced Vibration Analysis of a Cooling Water Pipeline for the HANARO CNS

International Nuclear Information System (INIS)

Kim, Bong Soo; Lee, Young Sub; Kim, Ik Soo; Kim, Young Ki

2007-01-01

CNS is the initial of Cold Neutron Source and the CNS facility system consists of hydrogen, a vacuum, a gas blanketing, a helium refrigeration and a cooling water supply system. Out of these subsystems, the helium refrigeration system has the function of removal of heat from a thermal neutron under reactor operation. Therefore, HRS (helium refrigeration system) must be under normal operation for the production of cold neutron. HRS is mainly made up of a helium compressor and a coldbox. This equipment is in need of cooling water to get rid of heat generation under stable operation and a cooling water system is essential to maintain the normal operation of a helium compressor and a coldbox. The main problem for the cooling water system is the vibration issue in the middle of operation due to a water flow in a pipeline. In order to suppress the vibration problem for a pipeline, the characteristics of a pipeline and fluid flow must be analyzed in detail. In this paper, fluid induced vibration of a cooling water pipe is analyzed numerically and the stability of the cooling water pipeline is investigated by using pipe dynamic theory

Numerical study of coupled heat and mass transfer in geothermal water cooling tower

International Nuclear Information System (INIS)

Bourouni, K.; Bassem, M.M.; Chaibi, M.T.

2008-01-01

Cross flow mechanical cooling towers, widely spreads all over the south region of Tunisia are used for cooling geothermal water for agriculture and domestic ends. These towers are sized empirically and present several problems in regard to operation and electrical energy consumption. This work aims to study the thermal behaviour of this type of cooling towers through a developed mathematical model considering the variation of the water mass flow rate inside the tower. The analysis of the water and air temperatures distribution along the cooling tower had underlined the negative convection phenomenon at a certain height of the tower. This analysis has shown also that the difference in water temperature between the inlet and the outlet of the tower is much higher than the one of air due to the dominance of the evaporative potential compared to the convective one. In addition, the variations of the air humidity along the cooling tower and the quantity of evaporated water have been investigated. The loss of water by evaporation is found to be 5.1% of the total quantity of water feeding the cooling tower. Interesting future prospects are expected for validation of the developed model to optimize the operating of the cooling tower

Cooling water distribution system

Science.gov (United States)

Orr, Richard

1994-01-01

A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

Performance characteristics of counter flow wet cooling towers

International Nuclear Information System (INIS)

Khan, Jameel-Ur-Rehman; Yaqub, M.; Zubair, Syed M.

2003-01-01

Cooling towers are one of the biggest heat and mass transfer devices that are in widespread use. In this paper, we use a detailed model of counter flow wet cooling towers in investigating the performance characteristics. The validity of the model is checked by experimental data reported in the literature. The thermal performance of the cooling towers is clearly explained in terms of varying air and water temperatures, as well as the driving potential for convection and evaporation heat transfer, along the height of the tower. The relative contribution of each mode of heat transfer rate to the total heat transfer rate in the cooling tower is established. It is demonstrated with an example problem that the predominant mode of heat transfer is evaporation. For example, evaporation contributes about 62.5% of the total rate of heat transfer at the bottom of the tower and almost 90% at the top of the tower. The variation of air and water temperatures along the height of the tower (process line) is explained on psychometric charts

Water cooling coil

Energy Technology Data Exchange (ETDEWEB)

Suzuki, S; Ito, Y; Kazawa, Y

1975-02-05

Object: To provide a water cooling coil in a toroidal nuclear fusion device, in which coil is formed into a small-size in section so as not to increase dimensions, weight or the like of machineries including the coil. Structure: A conductor arranged as an outermost layer of a multiple-wind water cooling coil comprises a hollow conductor, which is directly cooled by fluid, and as a consequence, a solid conductor disposed interiorly thereof is cooled indirectly.

Process for cooling waste water

Energy Technology Data Exchange (ETDEWEB)

Rohner, P

1976-12-16

The process for avoiding thermal pollution of waters described rests on the principle of the heat conduction tube, by which heat is conducted from the liquid space into the atmosphere at a lower temperature above it. Such a tube, here called a cooling tube, consists in its simplest form of a heat conducting corrugated tube, made, for example, of copper or a copper alloy or of precious metals, which is sealed to be airtight at both ends, and after evacuation, is partially filled with a medium of low boiling point. The longer leg of the tube, which is bent at right angles, lies close below the surface of the water to be cooled and parallel to it; the shorter leg projects vertically into the atmosphere. The liquid inside the cooling tube fills the horizontal part of the tube to about halfway. A certain part of the liquid is always evaporated in this part. The vapor rising in the vertical part of the tube condenses on the internal wall cooled by the air outside, and gives off its heat to the atmosphere. The condensed medium flows back down the vertical internal wall into the initial position in a continuous cycle. A further development contains a smooth plastic inner tube in an outer corrugated tube, which is shorter than the outer tube; it ends at a distance from the caps sealing the outer tube at both ends. In this design the angle between the vertical and horizontal leg is less than 90/sup 0/. The shorter leg projects vertically from the water surface, below which the longer leg rises slightly from the knee of tube. The quantity of the liquid is gauged as a type of siphon, so that the space between the outer and inner tube at the knee of the tube remains closed by the liquid medium. The medium evaporated from the surface in the long leg of the tube therefore flows over the inner tube, which starts above the level of the medium. Thus evaporation and condensation paths are separated.

Forced flow cooling of ISABELLE dipole magnets

International Nuclear Information System (INIS)

Bamberger, J.A.; Aggus, J.; Brown, D.P.; Kassner, D.A.; Sondericker, J.H.; Strobridge, T.R.

1976-01-01

The superconducting magnets for ISABELLE will use a forced flow supercritical helium cooling system. In order to evaluate this cooling scheme, two individual dipole magnets were first tested in conventional dewars using pool boiling helium. These magnets were then modified for forced flow cooling and retested with the identical magnet coils. The first evaluation test used a l m-long ISA model dipole magnet whose pool boiling performance had been established. The same magnet was then retested with forced flow cooling, energizing it at various operating temperatures until quench occurred. The magnet performance with forced flow cooling was consistent with data from the previous pool boiling tests. The next step in the program was a full-scale ISABELLE dipole ring magnet, 4.25 m long, whose performance was first evaluated with pool boiling. For the forced flow test the magnet was shrunk-fit into an unsplit laminated core encased in a stainless steel cylinder. The high pressure gas is cooled below 4 K by a helium bath which is pumped below atmospheric pressure with an ejector nozzle. The performance of the full-scale dipole magnet in the new configuration with forced flow cooling, showed a 10 percent increase in the attainable maximum current as compared to the pool boiling data

Heat transfer from a plate cooled by a water film with countercurrent air flow

International Nuclear Information System (INIS)

Ambrosini, W.; Manfredini, A.; Mariotti, F.; Oriolo, F.; Vigni, P.

1995-01-01

An experimental program at the University of Pisa provides specific data for the evaluation of heat and mass transfer by falling film evaporation. The problem is addressed primarily because of its relevance to the study of the behavior of passive containment cooling systems in simplified pressurized water reactors. In these plants, after an accident that releases vapor from the primary circuit, the steel containment envelope is cooled either by an ascending stream of air in natural circulation or by the combination of air flow and falling film evaporation. To qualify models for the prediction of the heat transfer capabilities in postulated accident conditions, researchers have built an experimental facility consisting of a flat heated plate with water sprays and a fan to simulate a countercurrent air stream. The range of relevant parameters to be investigated has been determined on the basis of integral calculations performed for the AP600 reactor containment. The facility has enabled the collection of data that confirm the adequacy of the classical heat and mass transfer analogy in predicting evaporation phenomena. Further developments in the research are needed to confirm the first results and to extend the experimental database by considering more subtle aspects of the phenomenon such as the characteristics of surface waviness of the water film and its effect on heat transfer

Cooling performance of helium-gas/water coolers in HENDEL

International Nuclear Information System (INIS)

Inagaki, Yoshiyuki; Takada, Shoji; Hayashi, Haruyoshi; Kobayashi, Toshiaki; Ohta, Yukimaru; Shimomura, Hiroaki; Miyamoto, Yoshiaki

1994-01-01

The helium engineering demonstration loop (HENDEL) has four helium-gas/water coolers where the cooling water flows in the tubes and helium gas on the shell side. Their cooling performance was studied using the operational data from 1982 to 1991. The heat transfer of helium gas on the shell was obtained for segmental and step-up baffle type coolers. Also, the change with operation time was investigated. The cooling performance was lowered by the graphite powder released from the graphite components for several thousand hours and thereafter recovered because the graphite powder from the components was reduced and the powder in the cooler shell was blown off during the operation. (orig.)

Water cooling of RF structures

International Nuclear Information System (INIS)

Battersby, G.; Zach, M.

1994-06-01

We present computer codes for heat transfer in water cooled rf cavities. RF parameters obtained by SUPERFISH or analytically are operated on by a set of codes using PLOTDATA, a command-driven program developed and distributed by TRIUMF [1]. Emphasis is on practical solutions with designer's interactive input during the computations. Results presented in summary printouts and graphs include the temperature, flow, and pressure data. (authors). 4 refs., 4 figs

The use of helical heat exchanger for heat recovery domestic water-cooled air-conditioners

International Nuclear Information System (INIS)

Yi Xiaowen; Lee, W.L.

2009-01-01

An experimental study on the performance of a domestic water-cooled air-conditioner (WAC) using tube-in-tube helical heat exchanger for preheating of domestic hot water was carried out. The main aims are to identify the comprehensive energy performance (space cooling and hot water preheating) of the WAC and the optimum design of the helical heat exchanger taking into account the variation in tap water flow rate. A split-type WAC was set up for experimental study at different indoor and outdoor conditions. The cooling output, the amount of recovered heat, and the power consumption for different hot water flow rates were measured. The experimental results showed that the cooling coefficient of performance (COP) of the WAC improves with the inclusion of the heat recovery option by a minimum of 12.3%. This can be further improved to 20.6% by an increase in tap water flow rate. Same result was observed for the comprehensive COP of the WAC. The maximum achievable comprehensive COP was 4.92 when the tap water flow rate was set at 7.7 L/min. The overall heat transfer coefficient of the helical heat exchanger under various operating conditions were determined by Wilson plot. A mathematical model relating the over all heat transfer coefficient to the outer pipe diameter was established which provides a convenient way of optimising the design of the helical heat exchanger

The Water Quality Control of the Secondary Cooling Water under a Normal Operation of 30 MWth in HANARO

International Nuclear Information System (INIS)

Park, Young Chul; Lee, Young Sub; Lim, Rag Yong

2008-01-01

HANARO, a multi-purpose research reactor, a 30 MWth open-tank-in-pool type, has been under a full power operation since 2005. The heat generated by the core of HANARO is transferred to the primary cooling water. And the cooling water transfers the heat to the secondary cooling water through the primary cooling heat exchanger. The heat absorbed by the secondary cooling water is removed through a cooling tower. The quality of the secondary cooling water is deteriorated by a temperature variation of the cooling water and a foreign material flowing over the cooling water through the cooling tower fan for a cooling. From these, a corrosion reduces the life time of a system, a scale degrades the heat transfer effect and a sludge and slime induces a local corrosion. For reducing these impacts, the quality of the secondary cooling water is treated by a high ca-hardness water quality program by maintaining a super saturated condition of ions, 12 of a ca-hardness concentration. After an overhaul maintenance of a secondary cooling tower composed of a secondary cooling system in 2007, a secondary cooling water stored in the cooling tower basin was replaced with a fresh city water. In this year, a water quality deterioration test has been performed under a full power operation and a mode of a twenty three day operation and twelve day maintenance for setting a beginning control limit of the secondary cooling water. This paper describes the water quality deterioration test for the secondary cooling system under a full power operation of 30 MWth including a test method, a test requirement and a test result

Contrastive analysis of cooling performance between a high-level water collecting cooling tower and a typical cooling tower

Science.gov (United States)

Wang, Miao; Wang, Jin; Wang, Jiajin; Shi, Cheng

2018-02-01

A three-dimensional (3D) numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower (HNDWCT) and a usual natural draft wet cooling tower (UNDWCT) under the actual operation condition at Wanzhou power plant, Chongqing, China. User defined functions (UDFs) of source terms are composed and loaded into the spray, fill and rain zones. Considering the conditions of impact on three kinds of corrugated fills (Double-oblique wave, Two-way wave and S wave) and four kinds of fill height (1.25 m, 1.5 m, 1.75 m and 2 m), numerical simulation of cooling performance are analysed. The results demonstrate that the S wave has the highest cooling efficiency in three fills for both towers, indicating that fill characteristics are crucial to cooling performance. Moreover, the cooling performance of the HNDWCT is far superior to that of the UNDWCT with fill height increases of 1.75 m and above, because the air mass flow rate in the fill zone of the HNDWCT improves more than that in the UNDWCT, as a result of the rain zone resistance declining sharply for the HNDWCT. In addition, the mass and heat transfer capacity of the HNDWCT is better in the tower centre zone than in the outer zone near the tower wall under a uniform fill layout. This behaviour is inverted for the UNDWCT, perhaps because the high-level collection devices play the role of flow guiding in the inner zone. Therefore, when non-uniform fill layout optimization is applied to the HNDWCT, the inner zone increases in height from 1.75 m to 2 m, the outer zone reduces in height from 1.75 m to 1.5 m, and the outlet water temperature declines approximately 0.4 K compared to that of the uniform layout.

Miniaturized compact water-cooled pitot-pressure probe for flow-field surveys in hypersonic wind tunnels

Science.gov (United States)

Ashby, George C.

1988-01-01

An experimental investigation of the design of pitot probes for flowfield surveys in hypersonic wind tunnels is reported. The results show that a pitot-pressure probe can be miniaturized for minimum interference effects by locating the transducer in the probe support body and water-cooling it so that the pressure-settling time and transducer temperature are compatible with hypersonic tunnel operation and flow conditions. Flowfield surveys around a two-to-one elliptical cone model in a 20-inch Mach 6 wind tunnel using such a probe show that probe interference effects are essentially eliminated.

Critical Design Issues of Tokamak Cooling Water System of ITER's Fusion Reactor

International Nuclear Information System (INIS)

Kim, Seokho H.; Berry, Jan

2011-01-01

U.S. ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). The TCWS transfers heat generated in the Tokamak to cooling water during nominal pulsed operation 850 MW at up to 150 C and 4.2 MPa water pressure. This water contains radionuclides because impurities (e.g., tritium) diffuse from in-vessel components and the vacuum vessel by water baking at 200 240 C at up to 4.4MPa, and corrosion products become activated by neutron bombardment. The system is designated as safety important class (SIC) and will be fabricated to comply with the French Order concerning nuclear pressure equipment (December 2005) and the EU Pressure Equipment Directive using ASME Section VIII, Div 2 design codes. The complexity of the TCWS design and fabrication presents unique challenges. Conceptual design of this one-of-a-kind cooling system has been completed with several issues that need to be resolved to move to next stage of the design. Those issues include flow balancing between over hundreds of branch pipelines in parallel to supply cooling water to blankets, determination of optimum flow velocity while minimizing the potential for cavitation damage, design for freezing protection for cooling water flowing through cryostat (freezing) environment, requirements for high-energy piping design, and electromagnetic impact to piping and components. Although the TCWS consists of standard commercial components such as piping with valves and fittings, heat exchangers, and pumps, complex requirements present interesting design challenges. This paper presents a brief description of TCWS conceptual design and critical design issues that need to be resolved.

An analytical model on thermal performance evaluation of counter flow wet cooling tower

Directory of Open Access Journals (Sweden)

Wang Qian

2017-01-01

Full Text Available This paper proposes an analytical model for simultaneous heat and mass transfer processes in a counter flow wet cooling tower, with the assumption that the enthalpy of the saturated air is a linear function of the water surface temperature. The performance of the proposed analytical model is validated in some typical cases. The validation reveals that, when cooling range is in a certain interval, the proposed model is not only comparable with the accurate model, but also can reduce computational complexity. In addition, with the proposed analytical model, the thermal performance of the counter flow wet cooling towers in power plants is calculated. The results show that the proposed analytical model can be applied to evaluate and predict the thermal performance of counter flow wet cooling towers.

Experimental study on the heat transfer characteristics of a nuclear reactor containment wall cooled by gravitationally falling water

Science.gov (United States)

Pasek, Ari D.; Umar, Efrison; Suwono, Aryadi; Manalu, Reinhard E. E.

2012-06-01

Gravitationally falling water cooling is one of mechanism utilized by a modern nuclear Pressurized Water Reactor (PWR) for its Passive Containment Cooling System (PCCS). Since the cooling is closely related to the safety, water film cooling characteristics of the PCCS should be studied. This paper deals with the experimental study of laminar water film cooling on the containment model wall. The influences of water mass flow rate and wall heat rate on the heat transfer characteristic were studied. This research was started with design and assembly of a containment model equipped with the water cooling system, and calibration of all measurement devices. The containment model is a scaled down model of AP 1000 reactor. Below the containment steam is generated using electrical heaters. The steam heated the containment wall, and then the temperatures of the wall in several positions were measure transiently using thermocouples and data acquisition. The containment was then cooled by falling water sprayed from the top of the containment. The experiments were done for various wall heat rate and cooling water flow rate. The objective of the research is to find the temperature profile along the wall before and after the water cooling applied, prediction of the water film characteristic such as means velocity, thickness and their influence to the heat transfer coefficient. The result of the experiments shows that the wall temperatures significantly drop after being sprayed with water. The thickness of water film increases with increasing water flow rate and remained constant with increasing wall heat rate. The heat transfer coefficient decreases as film mass flow rate increase due to the increases of the film thickness which causes the increasing of the thermal resistance. The heat transfer coefficient increases slightly as the wall heat rate increases. The experimental results were then compared with previous theoretical studied.

Influence of Stern Shaft Inclination on the Cooling Performance of Water-Lubricated Bearing

Directory of Open Access Journals (Sweden)

Zou Li

2016-01-01

Full Text Available The water film model of the marine water-lubricated stern bearing was established by FLUENT. The influence law of water flow rate on the cooling performance of water-lubricated bearing was studied in consideration of the stern shaft inclination. It will be helpful to improve the performance of marine water-lubricated stern bearing and both security and reliability of propulsion system. The simulation results show that the increase of cooling water flow rate in a certain range can effectively reduce bearing temperature. The bearing temperature rises sharply with thinning of water film thickness which is caused by the increase of inclination angle. Larger inclination angle can deteriorate the operating reliability of bearing.

Counter flow induced draft cooling tower option for supercritical carbon dioxide Brayton cycle

Energy Technology Data Exchange (ETDEWEB)

Pidaparti, Sandeep R., E-mail: sandeep.pidaparti@gmail.com [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA 30332 (United States); Moisseytsev, Anton; Sienicki, James J. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Ranjan, Devesh, E-mail: devesh.ranjan@me.gatech.edu [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA 30332 (United States)

2015-12-15

Highlights: • A code was developed to investigate the various aspects of using cooling tower for S-CO{sub 2} Brayton cycles. • Cooling tower option to reject heat is quantitatively compared to the direct water cooling and dry air cooling options. • Optimum water conditions resulting in minimal plant capital cost per unit power consumption are calculated. - Abstract: A simplified qualitative analysis was performed to investigate the possibility of using counter flow induced draft cooling tower option to reject heat from the supercritical carbon dioxide Brayton cycle for advanced fast reactor (AFR)-100 and advanced burner reactor (ABR)-1000 plants. A code was developed to estimate the tower dimensions, power and water consumption, and to perform economic analysis. The code developed was verified against a vendor provided quotation and is used to understand the effect of ambient air and water conditions on the design of cooling tower. The calculations indicated that there exists optimum water conditions for given ambient air conditions which will result in minimum power consumption, thereby increasing the cycle efficiency. A cost-based optimization technique is used to estimate the optimum water conditions which will improve the overall plant economics. A comparison of different cooling options for the S-CO{sub 2} cycle indicated that the cooling tower option is a much more practical and economical option compared to the dry air cooling or direct water cooling options.

Stochastic study on entrainment of floating particles with intake of cooling water of a power plant

International Nuclear Information System (INIS)

Kadoyu, Masatake; Wada, Akira

1979-01-01

The mortality of ichthyoplanktons, contained in the sea water passing through the cooling water systems of a power plant, may be associated with rising temperature and mechanical effect. In this study, the range and the rate of entrainment of the organisms like ichthyoplanktons floating in the sea caused by the intake of cooling water were stochastically investigated by simulating the average current as well as the flow caused by the intake of water and by taking into consideration random velocity fluctuation without these flows, using a mathematical model. An intake was set along the straight coastline in semi-infinite sea, and the rate of inflow of particles into the intake was simulated by a mathematical model. In the numerical simulation, the average flow as coastal current component and the flow caused by the intake of water were obtained with the hydrodynamic equations of motion and continuity, and the rate of entrainment of floating particles was examined by giving turbulence to the particles in the sea and by calculating the position of each particle every moment. The results are as follows; 1) The range of entrainment of floating particles by the intake of cooling water and its probability were obtained in consideration of the flow rate of cooling water, coast current velocity and diffusion coefficient as parameters. 2) The extent of inflow of floating particles considerably varied with tidal amplitude, diffusion coefficient and the flow rate of cooling water in the sea where the coastal flow has clear periodicity. 3) The extent of entrainment was considerably influenced by the steady current velocity, the velocity distribution in offshore direction and the intake volume in the sea where periodicity is not observed. (Nakai, Y.)

Corrosion evaluation of cooling-water treatments for gas centrifuge facilities

International Nuclear Information System (INIS)

Schmidt, C.R.; Meredith, P.F.

1980-01-01

The corrosion resistance of six different types of weighted metal coupons was evaluated at 29 0 C (84 0 F) in flowing water containing nitrite-borate-silicate corrosion inhibitors. The question for evaluation was whether it would be more advantageous: (1) to drain the treated cooling water from the centrifuge machine and to expose them to moisture-laden air over an assumed shop downtime and repair perid of 1 month; or (2) to let the treated cooling water remain stagnant in the machines during this downtime. The moisture-laden-air exposure was more detrimental

Review on Water Distribution of Cooling Tower in Power Station

Science.gov (United States)

Huichao, Zhang; Lei, Fang; Hao, Guang; Ying, Niu

2018-04-01

As the energy sources situation is becoming more and more severe, the importance of energy conservation and emissions reduction gets clearer. Since the optimization of water distribution system of cooling tower in power station can save a great amount of energy, the research of water distribution system gets more attention nowadays. This paper summarizes the development process of counter-flow type natural draft wet cooling tower and the water distribution system, and introduces the related domestic and international research situation. Combining the current situation, we come to the conclusion about the advantages and disadvantages of the several major water distribution modes, and analyze the problems of the existing water distribution ways in engineering application, furthermore, we put forward the direction of water distribution mode development on the basis knowledge of water distribution of cooling tower. Due to the water system can hardly be optimized again when it’s built, choosing an appropriate water distribution mode according to actual condition seems to be more significant.

Cooling tower calculations

International Nuclear Information System (INIS)

Simonkova, J.

1988-01-01

The problems are summed up of the dynamic calculation of cooling towers with forced and natural air draft. The quantities and relations are given characterizing the simultaneous exchange of momentum, heat and mass in evaporative water cooling by atmospheric air in the packings of cooling towers. The method of solution is clarified in the calculation of evaporation criteria and thermal characteristics of countercurrent and cross current cooling systems. The procedure is demonstrated of the calculation of cooling towers, and correction curves and the effect assessed of the operating mode at constant air number or constant outlet air volume flow on their course in ventilator cooling towers. In cooling towers with the natural air draft the flow unevenness is assessed of water and air relative to its effect on the resulting cooling efficiency of the towers. The calculation is demonstrated of thermal and resistance response curves and cooling curves of hydraulically unevenly loaded towers owing to the water flow rate parameter graded radially by 20% along the cross-section of the packing. Flow rate unevenness of air due to wind impact on the outlet air flow from the tower significantly affects the temperatures of cooled water in natural air draft cooling towers of a design with lower demands on aerodynamics, as early as at wind velocity of 2 m.s -1 as was demonstrated on a concrete example. (author). 11 figs., 10 refs

Recolonization of reactor cooling water system by the Asiatic clam Corbicula fluminea

International Nuclear Information System (INIS)

Harvey, R.S.

1978-01-01

Recolonization rates for the Asiatic clam Corbicula fluminea ranged from 3.0 to 5.6 metric tons per year in cooling water basins for a nuclear production reactor at the Savannah River Plant. However, a 10-month cleaning cycle for each basin (flow area, 6100 m 2 ) keeps the depth of the silt/clam layer low. With this cleaning frequency, Corbicula are not reaching heat exchangers at sufficient size or in sufficient numbers to restrict flow. Data are presented on the size/age distribution for clams recolonizing cooling water basins between cleanings

A simpler, safer, higher performance cooling system arrangement for water cooled divertors

International Nuclear Information System (INIS)

Carelli, M.D.; Kothmann, R.E.; Green, L.; Zhan, N.J.; Stefani, F.; Roidt, R.M.

1994-01-01

A cooling system arrangement is presented which is specifically designed for high heat flux water cooled divertors. The motivation behind the proposed open-quotes unichannelclose quotes configuration is to provide maximum safety; this design eliminates flow instabilities liable to occur in parallel channel designs, it eliminates total blockage, it promotes cross flow to counteract the effects of partial blockage and/or local hot spots, and it is much more tolerant to the effects of debonding between the beryllium armor and the copper substrate. Added degrees of freedom allow optimization of the design, including the possibility of operating at very high heat transfer coefficients associated with nucleate boiling, while at the same time providing ample margin against departure from nucleate boiling. Projected pressure drop, pumping power, and maximum operating temperatures are lower than for conventional parallel channel designs

Study of Cooling Characteristic of The Containment APWR Model Using Laminar Subcooled Water Film

International Nuclear Information System (INIS)

Diah Hidayanti; Aryadi Suwono; Nathanael P Tandian; Ari Darmawan Pasek; Efrizon Umar

2009-01-01

One of mechanism utilized by the next-generation pressurized water reactor for cooling its containment passively is gravitationally falling water spray cooling. This paper focuses on the characteristic study using Fluent 5/6 program for the case of the containment outer wall cooling by laminar sub-cooled water film. The cooling system characteristics which will be discussed consist of water film thickness and temperature on all parts of the containment wall as well as the effect of water spray volume flow rate on the water film thickness and convection heat transfer capability from the containment wall to the film bulk. In addition, some kinds of non dimensional numbers involved in the film heat transfer correlation will be presented in this paper. (author)

Exergy transfer and parametric study of counter flow wet cooling towers

International Nuclear Information System (INIS)

Wang Li; Li Nianping

2011-01-01

A thermodynamic analysis of the counter flow wet cooling tower (CWCT) is performed in this paper. Both energy and exergy formulations are developed and validated for the system. Four types of exergy transfer processes occurring inside the CWCT are investigated schematically. A parametric study is conducted under various operating conditions in order to investigate the effects of thermal efficiency and water-to-air ratio on the exergy performance of the CWCT. Unlike past studies, the transiting exergy contained in the inlet and outlet water is not considered. It is found that the exergy efficiency is always less than 25%. The exergy parameters including evaporation water loss, exergy efficiency, exergy input, internal and external exergy losses are very sensitive to the thermal efficiency when it is very close to 1.0 at lower water-to-air ratios. - Research highlights: → We model counter flow wet cooling towers and make a detailed exergy analysis. → Four types of exergy transfer processes are investigated schematically. → Only a small part of exergy input, less than 25%, is effectively utilized.

Development of the interactive model between Component Cooling Water System and Containment Cooling System using GOTHIC

International Nuclear Information System (INIS)

Byun, Choong Sup; Song, Dong Soo; Jun, Hwang Yong

2006-01-01

In a design point of view, component cooling water (CCW) system is not full-interactively designed with its heat loads. Heat loads are calculated from the CCW design flow and temperature condition which is determined with conservatism. Then the CCW heat exchanger is sized by using total maximized heat loads from above calculation. This approach does not give the optimized performance results and the exact trends of CCW system and the loads during transient. Therefore a combined model for performance analysis of containment and the component cooling water(CCW) system is developed by using GOTHIC software code. The model is verified by using the design parameters of component cooling water heat exchanger and the heat loads during the recirculation mode of loss of coolant accident scenario. This model may be used for calculating the realistic containment response and CCW performance, and increasing the ultimate heat sink temperature limits

Cooling clothing utilizing water evaporation

DEFF Research Database (Denmark)

Sakoi, Tomonori; Tominaga, Naoto; Melikov, Arsen Krikor

2014-01-01

. To prevent wet discomfort, the T-shirt was made of a polyester material having a water-repellent silicon coating on the inner surface. The chest, front upper arms, and nape of the neck were adopted as the cooling areas of the human body. We conducted human subject experiments in an office with air......We developed cooling clothing that utilizes water evaporation to cool the human body and has a mechanism to control the cooling intensity. Clean water was supplied to the outer surface of the T-shirt of the cooling clothing, and a small fan was used to enhance evaporation on this outer surface...... temperature ranging from 27.4 to 30.7 °C to establish a suitable water supply control method. A water supply control method that prevents water accumulation in the T-shirt and water dribbling was validated; this method is established based on the concept of the water evaporation capacity under the applied...

WRI 50: Strategies for Cooling Electric Generating Facilities Utilizing Mine Water

Energy Technology Data Exchange (ETDEWEB)

Joseph J. Donovan; Brenden Duffy; Bruce R. Leavitt; James Stiles; Tamara Vandivort; Paul Ziemkiewicz

2004-11-01

Power generation and water consumption are inextricably linked. Because of this relationship DOE/NETL has funded a competitive research and development initiative to address this relationship. This report is part of that initiative and is in response to DOE/NETL solicitation DE-PS26-03NT41719-0. Thermal electric power generation requires large volumes of water to cool spent steam at the end of the turbine cycle. The required volumes are such that new plant siting is increasingly dependent on the availability of cooling circuit water. Even in the eastern U.S., large rivers such as the Monongahela may no longer be able to support additional, large power stations due to subscription of flow to existing plants, industrial, municipal and navigational requirements. Earlier studies conducted by West Virginia University (WV 132, WV 173 phase I, WV 173 Phase II, WV 173 Phase III, and WV 173 Phase IV in review) have identified that a large potential water resource resides in flooded, abandoned coal mines in the Pittsburgh Coal Basin, and likely elsewhere in the region and nation. This study evaluates the technical and economic potential of the Pittsburgh Coal Basin water source to supply new power plants with cooling water. Two approaches for supplying new power plants were evaluated. Type A employs mine water in conventional, evaporative cooling towers. Type B utilizes earth-coupled cooling with flooded underground mines as the principal heat sink for the power plant reject heat load. Existing mine discharges in the Pittsburgh Coal Basin were evaluated for flow and water quality. Based on this analysis, eight sites were identified where mine water could supply cooling water to a power plant. Three of these sites were employed for pre-engineering design and cost analysis of a Type A water supply system, including mine water collection, treatment, and delivery. This method was also applied to a ''base case'' river-source power plant, for comparison. Mine-water

Closed-cycle process of coke-cooling water in delayed coking unit

International Nuclear Information System (INIS)

Zhou, P.; Bai, Z.S.; Yang, Q.; Ma, J.; Wang, H.L.

2008-01-01

Synthesized processes are commonly used to treat coke-cooling wastewater. These include cold coke-cut water, diluting coke-cooling water, adding chemical deodorization into oily water, high-speed centrifugal separation, de-oiling and deodorization by coke adsorption, and open nature cooling. However, because of water and volatile evaporation loss, it is not suitable to process high-sulphur heavy oil using open treatments. This paper proposed a closed-cycling process in order to solve the wastewater treatment problem. The process is based on the characteristics of coke-cooling water, such as rapid parametric variation, oil-water-coke emulsification and steam-water mixing. The paper discussed the material characteristics and general idea of the study. The process of closed-cycle separation and utilization process of coke-cooling water was presented along with a process flow diagram. Several applications were presented, including a picture of hydrocyclones for pollution separation and a picture of equipments of pollution separation and components regeneration. The results showed good effect had been achieved since the coke-cooling water system was put into production in 2004. The recycling ratios for the components of the coke-cooling water were 100 per cent, and air quality in the operating area reached the requirements of the national operating site circumstance and the health standards. Calibration results of the demonstration unit were presented. It was concluded that since the devices went into operation, the function of production has been normal and stable. The operation was simple, flexible, adjustable and reliable, with significant economic efficiency and environmental benefits. 10 refs., 2 tabs., 3 figs

Measurement of Quasi-periodic Oscillating Flow Motion in Simulated Dual-cooled Annular Fuel Bundle

International Nuclear Information System (INIS)

Lee, Chi Young; Shin, Chang Hwan; Park, Ju Yong; Oh, Dong Seok; Chun, Tae Hyun; In, Wang Kee

2012-01-01

In order to increase a significant amount of reactor power in OPR1000, KAERI (Korea Atomic Energy Research Institute) has been developing a dual-cooled annular fuel. The dual-cooled annular fuel is simultaneously cooled by the water flow through the inner and the outer channels. KAERI proposed the 12x12 dual-cooled annular fuel array which was designed to be structurally compatible with the 16x16 cylindrical solid fuel array by maintaining the same array size and the guide tubes in the same locations, as shown in Fig. 1. In such a case, due to larger outer diameter of dual-cooled annular fuel than conventional solid fuel, a P/D (Pitch-to-Diameter ratio) of dual cooled annular fuel assembly becomes smaller than that of cylindrical solid fuel. A change in P/D of fuel bundle can cause a difference in the flow mixing phenomena between the dual-cooled annular and conventional cylindrical solid fuel assemblies. In this study, the rod bundle flow motion appearing in a small P/D case is investigated preliminarily using PIV (Particle Image Velocimetry) for dual-cooled annular fuel application

Calculation of mass flow and steam quality distribution on fuel elements of light-water cooled boiling water nuclear reactors

International Nuclear Information System (INIS)

Hermanns, H.J.

1977-04-01

By the example of light-water cooled nuclear reactors, the state of the calculation methods at disposal for calculating mass flow and steam quality distribution (sub-channel analysis) is indicated. Particular regard was paid to the transport phenomena occurring in reactor fuel elements in the range of two phase flow. Experimentally determined values were compared with recalculations of these experiments with the sub-channel code COBRA; from the results of these comparing calculations, conclusions could be drawn on the suitability of this code for defined applications. Limits of reliability could be determined to some extent. Based on the experience gained and the study of individual physical model concepts, recognized as being important, a sub-channel model was drawn up and the corresponding numerical computer code (SIEWAS) worked out. Experiments made at GE could be reproduced with the code SIEWAS with sufficient accuracy. (orig.) [de

INVESTIGATION OF THE PERFORMANCE OF AN ATMOSPHERIC COOLING TOWER USING FRESH AND SALTED WATER

Directory of Open Access Journals (Sweden)

A Haddad

2012-01-01

Full Text Available Cooling towers are extensively used to evacuate large quantities of heat at modest temperatures through a change of phase of the flowing cooling fluid. Based on this classical principle, the present study investigates the influence of salty water on the heat exchange produced. For that purpose, experiments are carried out using fresh and salty water. Furthermore, a comparison with the results produced through an approach involving the solution of energy equation involving the flow of air on an evaporating film of fluid. The detailed results show a preponderance of fresh water over the salty.

Atmospheric cooling tower with reduced plume

International Nuclear Information System (INIS)

Gautier, D.M.; Lagoutte, A.

1985-01-01

The cooling tower, usable in thermal-electric power plants, has a vertical chimney having a central water tower fed with water to be cooled, a pipe network distributing water coming from the water tower and dispersing it in flows streaming down on a packing, and a basin to receive the water cooled by contact with an air flow passing through apertures at the lower part of the chimney and flowing up through the chimney. The cooling tower has inlet air pipes for the said apertures to a zone of the chimney situated beyond the streaming zone, the said pipes being arranged such their surface is swept by water to be cooled [fr

Passive containment cooling water distribution device

Science.gov (United States)

Conway, Lawrence E.; Fanto, Susan V.

1994-01-01

A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using a series of radial guide elements and cascading weir boxes to collect and then distribute the cooling water into a series of distribution areas through a plurality of cascading weirs. The cooling water is then uniformly distributed over the curved surface by a plurality of weir notches in the face plate of the weir box.

Topological charge using cooling and the gradient flow

International Nuclear Information System (INIS)

Alexandrou, C.; Athenodorou, A.; The Cyprus Institute, Nicosia; Jansen, K.

2015-12-01

The equivalence of cooling to the gradient flow when the cooling step n c and the continuous flow step of gradient flow τ are matched is generalized to gauge actions that include rectangular terms. By expanding the link variables up to subleading terms in perturbation theory, we relate n c and τ and show that the results for the topological charge become equivalent when rescaling τ ≅ n c /(3-15c 1 ) where c 1 is the Symanzik coefficient multiplying the rectangular term. We, subsequently, apply cooling and the gradient flow using the Wilson, the Symanzik tree-level improved and the Iwasaki gauge actions to configurations produced with N f = 2 + 1 + 1 twisted mass fermions. We compute the topological charge, its distribution and the correlators between cooling and gradient flow at three values of the lattice spacing demonstrating that the perturbative rescaling τ ≅ n c /(3-15c 1 ) leads to equivalent results.

Cooling system upon reactor isolation

International Nuclear Information System (INIS)

Yamamoto, Kohei; Oda, Shingo; Miura, Satoshi

1992-01-01

A water level indicator for detecting the upper limit value for a range of using a suppression pool and a thermometer for detecting the temperature of water at the cooling water inlet of an auxiliary device are disposed. When a detection signal is intaken and the water level in the suppression pool reach the upper limit value for the range of use, a secondary flow rate control value is opened and a primary flow rate control valve is closed. When the temperature of the water at the cooling water inlet of the auxiliary device reaches the upper limit value, the primary and the secondary flow rate control valves are opened. During a stand-by state, the first flow rate control valve is set open and the secondary flow rate control valve is set closed respectively. After reactor isolation, if a reactor water low level signal is received, an RCIC pump is actuated and cooling water is sent automatically under pressure from a condensate storage tank to the reactor and the auxiliary device requiring coolants by way of the primary flow rate control valve. Rated flow rate is ensured in the reactor and cooling water of an appropriate temperature can be supplied to the auxiliary device. (N.H.)

Performance Optimization of the Water Cooling System for Resonance Frequency Control of the PEFP DTL

International Nuclear Information System (INIS)

Kim, K. Y.; Kim, H. K.; Kim, H. S.; Yoon, J. C.; Sohn, Y. K.; Kweon, S. J.; Park, J.; Kim, K. S.

2010-03-01

The objective of in this research project is prototype cooling water skid of separated closed loop in order to supply and withdraw low conductivity deionized water in drift tube of drift tube linac as core components of proton accelerates. This report is dealt with design specification of J-PARC 400 MeV Linac cooling water system, PEFP DTL cooling system, specification of RCCS21-24, RCCS101 with pump, loss coefficient for DTL2 modeling, pressure drop with flow rate of heat exchanger.

Mathematical Model and Program for the Sizing of Counter-flow Natural Draft Wet Cooling Towers

Directory of Open Access Journals (Sweden)

Victor-Eduard Cenușă

2017-08-01

Full Text Available Assuring the necessary temperature and mass flow rate of the cooling water to the condenser represents an essential condition for the efficient operation of a steam power plant. The paper presents equations which describe the physical phenomena and the mathematical model for the design of counter-flow natural draft wet cooling towers. Following is given the flow-chart of the associated computer program. A case study is made to show the results of the computer program and emphasize the interdependence between the main design parameters.

Heat transfer enhancement in a natural draft dry cooling tower under crosswind operation with heterogeneous water distribution

Energy Technology Data Exchange (ETDEWEB)

Goodarzi, Mohsen; Amooie, Hossein [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2016-04-15

Crosswind significantly decreases cooling efficiency of a natural draft dry cooling tower. The possibility of improving cooling efficiency with heterogeneous water distribution within the cooling tower radiators under crosswind condition is analysed. A CFD approach was used to model the flow field and heat transfer phenomena within the cooling tower and airflow surrounding the cooling tower. A mathematical model was developed from various CFD results. Having used a trained Genetic Algorithm with the result of mathematical model, the best water distribution was found among the others. Remodeling the best water distribution with the CFD approach showed that the highest enhancement of the heat transfer compared to the usual uniform water distribution.

Heat transfer enhancement in a natural draft dry cooling tower under crosswind operation with heterogeneous water distribution

International Nuclear Information System (INIS)

Goodarzi, Mohsen; Amooie, Hossein

2016-01-01

Crosswind significantly decreases cooling efficiency of a natural draft dry cooling tower. The possibility of improving cooling efficiency with heterogeneous water distribution within the cooling tower radiators under crosswind condition is analysed. A CFD approach was used to model the flow field and heat transfer phenomena within the cooling tower and airflow surrounding the cooling tower. A mathematical model was developed from various CFD results. Having used a trained Genetic Algorithm with the result of mathematical model, the best water distribution was found among the others. Remodeling the best water distribution with the CFD approach showed that the highest enhancement of the heat transfer compared to the usual uniform water distribution.

Numerically Analysed Thermal Condition of Hearth Rollers with the Water-Cooled Shaft

Directory of Open Access Journals (Sweden)

A. V. Ivanov

2016-01-01

Full Text Available Continuous furnaces with roller hearth have wide application in the steel industry. Typically, furnaces with roller hearth belong to the class of medium-temperature heat treatment furnaces, but can be used to heat the billets for rolling. In this case, the furnaces belong to the class of high temperature heating furnaces, and their efficiency depends significantly on the reliability of the roller hearth furnace. In the high temperature heating furnaces are used three types of watercooled shaft rollers, namely rollers without insulation, rollers with insulating screens placed between the barrel and the shaft, and rollers with bulk insulation. The definition of the operating conditions of rollers with water-cooled shaft greatly facilitates the choice of their design parameters when designing. In this regard, at the design stage of the furnace with roller hearth, it is important to have information about the temperature distribution in the body of the rollers at various operating conditions. The article presents the research results of the temperature field of the hearth rollers of metallurgical heating furnaces. Modeling of stationary heat exchange between the oven atmosphere and a surface of rollers, and between the cooling water and shaft was executed by finite elements method. Temperature fields in the water-cooled shaft rollers of various designs are explored. The water-cooled shaft rollers without isolation, rollers with screen and rollers with bulk insulation, placed between the barrel and the water-cooled shaft were investigated. Determined the change of the thermo-physic parameters of the coolant, the temperature change of water when flowing in a pipe and shaft, as well as the desired pressure to supply water with a specified flow rate. Heat transfer coefficients between the cooling water and the shaft were determined directly during the solution based on the specified boundary conditions. Found that the greatest heat losses occur in the

Using containment analysis to improve component cooling water heat exchanger limits

International Nuclear Information System (INIS)

Da Silva, H.C.; Tajbakhsh, A.

1995-01-01

The Comanche Peak Steam Electric Station design requires that exit temperatures from the Component Cooling Water Heat Exchanger remain below 330.37 K during the Emergency Core Cooling System recirculation stage, following a hypothetical Loss of Coolant Accident (LOCA). Due to measurements indicating a higher than expected combination of: (a) high fouling factor in the Component Cooling Water Heat Exchanger with (b) high ultimate heat sink temperatures, that might lead to temperatures in excess of the 330.37 K limit, if a LOCA were to occur, TUElectric adjusted key flow rates in the Component Cooling Water network. This solution could only be implemented with improvements to the containment analysis methodology of record. The new method builds upon the CONTEMPT-LT/028 code by: (a) coupling the long term post-LOCA thermohydraulics with a more detailed analytical model for the complex Component Cooling Water Heat Exchanger network and (b) changing the way mass and energy releases are calculated after core reflood and steam generator energy is dumped to the containment. In addition, a simple code to calculate normal cooldowns was developed to confirm RHR design bases were met with the improved limits

An Approach for Selection of Flow Regime and Models for Conservative Evaluation of a Vessel Integrity Monitoring System for Water-Cooled Vacuum Vessels

International Nuclear Information System (INIS)

Pointer, W. David; Ruggles, Arthur E.

2003-01-01

Thin-walled vacuum containment vessels cooled by circulating water jackets are often utilized in research and industrial applications where isolation of equipment or experiments from the influences of the surrounding environment is desirable. The development of leaks in these vessels can result in costly downtime for the facility. A Vessel Integrity Monitoring System (VIMS) is developed to detect leak formation and estimate the size of the leak to allow evaluation of the risk associated with continued operation. A wide range of leak configurations and fluid flow phenomena are considered in the evaluation of the rate at which a tracer gas dissolved in the cooling jacket water is transported into the vacuum vessel. A methodology is presented that uses basic fluid flow models and careful evaluation of their ranges of applicability to provide a conservative estimate of the transport rates for the tracer gas and hence the time required for the VIMS to detect a leak of a given size

Problems of two-phase flows in water cooled and moderated reactors

International Nuclear Information System (INIS)

Syu, Yu.

1984-01-01

Heat exchange in two-phase flows of coolant in loss of coolant accidents in PWR and BWR reactors has been investigated. Three main stages of accident history are considered: blowdown, reflooding using emergency core cooling system and rewetting. Factors, determining the rate of coolant leakage and the rate of temperature increase in fuel cladding during blowdown, processes of vapour during reflooding and liquid priming by vapour during rewetting, are discussed

Offshore Floating Wind Turbine-driven Deep Sea Water Pumping for Combined Electrical Power and District Cooling

Science.gov (United States)

Sant, T.; Buhagiar, D.; Farrugia, R. N.

2014-06-01

A new concept utilising floating wind turbines to exploit the low temperatures of deep sea water for space cooling in buildings is presented. The approach is based on offshore hydraulic wind turbines pumping pressurised deep sea water to a centralised plant consisting of a hydro-electric power system coupled to a large-scale sea water-cooled air conditioning (AC) unit of an urban district cooling network. In order to investigate the potential advantages of this new concept over conventional technologies, a simplified model for performance simulation of a vapour compression AC unit was applied independently to three different systems, with the AC unit operating with (1) a constant flow of sea surface water, (2) a constant flow of sea water consisting of a mixture of surface sea water and deep sea water delivered by a single offshore hydraulic wind turbine and (3) an intermittent flow of deep sea water pumped by a single offshore hydraulic wind turbine. The analysis was based on one year of wind and ambient temperature data for the Central Mediterranean that is known for its deep waters, warm climate and relatively low wind speeds. The study confirmed that while the present concept is less efficient than conventional turbines utilising grid-connected electrical generators, a significant portion of the losses associated with the hydraulic transmission through the pipeline are offset by the extraction of cool deep sea water which reduces the electricity consumption of urban air-conditioning units.

Offshore Floating Wind Turbine-driven Deep Sea Water Pumping for Combined Electrical Power and District Cooling

International Nuclear Information System (INIS)

Sant, T; Buhagiar, D; Farrugia, R N

2014-01-01

A new concept utilising floating wind turbines to exploit the low temperatures of deep sea water for space cooling in buildings is presented. The approach is based on offshore hydraulic wind turbines pumping pressurised deep sea water to a centralised plant consisting of a hydro-electric power system coupled to a large-scale sea water-cooled air conditioning (AC) unit of an urban district cooling network. In order to investigate the potential advantages of this new concept over conventional technologies, a simplified model for performance simulation of a vapour compression AC unit was applied independently to three different systems, with the AC unit operating with (1) a constant flow of sea surface water, (2) a constant flow of sea water consisting of a mixture of surface sea water and deep sea water delivered by a single offshore hydraulic wind turbine and (3) an intermittent flow of deep sea water pumped by a single offshore hydraulic wind turbine. The analysis was based on one year of wind and ambient temperature data for the Central Mediterranean that is known for its deep waters, warm climate and relatively low wind speeds. The study confirmed that while the present concept is less efficient than conventional turbines utilising grid-connected electrical generators, a significant portion of the losses associated with the hydraulic transmission through the pipeline are offset by the extraction of cool deep sea water which reduces the electricity consumption of urban air-conditioning units

Cooling water systems design using process integration

CSIR Research Space (South Africa)

Gololo, KV

2010-09-01

Full Text Available Cooling water systems are generally designed with a set of heat exchangers arranged in parallel. This arrangement results in higher cooling water flowrate and low cooling water return temperature thus reducing cooling tower efficiency. Previous...

Improving of the photovoltaic / thermal system performance using water cooling technique

International Nuclear Information System (INIS)

Hussien, Hashim A; Numan, Ali H; Abdulmunem, Abdulmunem R

2015-01-01

This work is devoted to improving the electrical efficiency by reducing the rate of thermal energy of a photovoltaic/thermal system (PV/T).This is achieved by design cooling technique which consists of a heat exchanger and water circulating pipes placed at PV module rear surface to solve the problem of the high heat stored inside the PV cells during the operation. An experimental rig is designed to investigate and evaluate PV module performance with the proposed cooling technique. This cooling technique is the first work in Iraq to dissipate the heat from PV module. The experimental results indicated that due to the heat loss by convection between water and the PV panel's upper surface, an increase of output power is achieved. It was found that without active cooling, the temperature of the PV module was high and solar cells could only achieve a conversion efficiency of about 8%. However, when the PV module was operated under active water cooling condition, the temperature was dropped from 76.8°C without cooling to 70.1°C with active cooling. This temperature dropping led to increase in the electrical efficiency of solar panel to 9.8% at optimum mass flow rate (0.2L/s) and thermal efficiency to (12.3%). (paper)

Determining the void fraction in draught sections of a boiling water cooled reactor

International Nuclear Information System (INIS)

Fedulin, V.N.; Barolomej, G.G.; Solodkij, V.A.; Shmelev, V.E.

1987-01-01

Consideration is being given to the problem of improving methods for calculation of the void fraction in large channels of cooling system of the boiling water cooled reactor during two-phase unsteady flow. Investigation of the structure of two-phase flow was conducted in draught section of the VK-50 reactor (diameter D=2 m, height H=3). The method for calculation of the void fraction in channels with H/D ratio close to 1 is suggested

Safety analysis of a high temperature supercritical pressure light water cooled and moderated reactor

International Nuclear Information System (INIS)

Ishiwatari, Y.; Oka, Y.; Koshizuka, S.

2002-01-01

A safety analysis code for a high temperature supercritical pressure light water cooled reactor (SCLWR-H) with water rods cooled by descending flow, SPRAT-DOWN, is developed. The hottest channel, a water rod, down comer, upper and lower plenums, feed pumps, etc. are modeled as junction of nodes. Partial of the feed water flows downward from the upper dome of the reactor pressure vessel to the water rods. The accidents analyzed here are total loss of feed water flow, feed water pump seizure, and control rods ejection. All the accidents satisfy the criteria. The accident event at which the maximum cladding temperature is the highest is total loss of feedwater flow. The transients analyzed here are loss of feed water heating, inadvertent start-up of an auxiliary water supply system, partial loss of feed water flow, loss of offsite power, loss of load, and abnormal withdrawal of control rods. All the transients satisfied the criteria. The transient event for which the maximum cladding temperature is the highest is control rod withdrawal at normal operation. The behavior of loss of load transient is different from that of BWR. The power does not increase because loss of flow occurs and the density change is small. The sensitivities of the system behavior to various parameters during transients and accidents are analyzed. The parameters having strong influence are the capacity of the auxiliary water supply system, the coast down time of the main feed water pumps, and the time delay of the main feed water pumps trip. The control rod reactivity also has strong influence. (authors)

Emergency cooling system for a liquid metal cooled reactor

International Nuclear Information System (INIS)

Murata, Ryoichi; Fujiwara, Toshikatsu.

1980-01-01

Purpose: To suitably cool liquid metal as coolant in emergency in a liquid metal cooled reactor by providing a detector for the pressure loss of the liquid metal passing through a cooling device in a loop in which the liquid metal is flowed and communicating the detector with a coolant flow regulator. Constitution: A nuclear reactor is stopped in nuclear reaction by control element or the like in emergency. If decay heat is continuously generated for a while and secondary coolant is insufficiently cooled with water or steam flowed through a steam and water loop, a cooler is started. That is, low temperature air is supplied by a blower through an inlet damper to the cooler to cool the secondary coolant flowed into the cooler through a bypass pipe so as to finally safely stop an entire plant. Since the liquid metal is altered in its physical properties by the temperature at this time, it is detected to regulate the opening of the valve of the damper according to the detected value. (Sekiya, K.)

Thermal analysis of mass concrete embedded with double-layer staggered heterogeneous cooling water pipes

International Nuclear Information System (INIS)

Yang Jian; Hu Yu; Zuo Zheng; Jin Feng; Li Qingbin

2012-01-01

Removal of hydration heat from mass concrete during construction is important for the quality and safety of concrete structures. In this study, a three-dimensional finite element program for thermal analysis of mass concrete embedded with double-layer staggered heterogeneous cooling water pipes was developed based on the equivalent equation of heat conduction including the effect of cooling water pipes and hydration heat of concrete. The cooling function of the double-layer staggered heterogeneous cooling pipes in a concrete slab was derived from the principle of equivalent cooling. To improve the applicability and precision of the equivalent heat conduction equation under small flow, the cooling function was revised according to its monotonicity and empirical formulas of single-phase forced-convection heat transfer in tube flow. Considering heat hydration of concrete at later age, a double exponential function was proposed to fit the adiabatic temperature rise curve of concrete. Subsequently, the temperature variation of concrete was obtained, and the outlet temperature of cooling water was estimated through the energy conservation principle. Comparing calculated results with actual measured data from a monolith of an arch dam in China, the numerical model was proven to be effective in sufficiently simulating accurate temperature variations of mass concrete. - Highlights: ► Three-dimensional program is developed to model temperature history of mass concrete. ► Massive concrete is embedded with double-layer heterogeneous cooling pipes. ► Double exponential function is proposed to fit the adiabatic temperature rise curve. ► Outlet temperature of cooling water is estimated. ► A comparison is made between the calculated and measured data.

Mycobacteria in Finnish cooling tower waters.

Science.gov (United States)

Torvinen, Eila; Suomalainen, Sini; Paulin, Lars; Kusnetsov, Jaana

2014-04-01

Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination. © 2013 APMIS. Published by John Wiley & Sons Ltd.

Demineralised water cooling in the LHC accelerator

CERN Document Server

Peón-Hernández, G

2002-01-01

In spite of the LHC accelerator being a cryogenic machine, it remains nevertheless a not negligible heat load to be removed by conventional water-cooling. About 24MW will be taken away by demineralised water cooled directly by primary water from the LHC cooling towers placed at the even points. This paper describes the demineralised water network in the LHC tunnel including pipe diameters, lengths, water speed, estimated friction factor, head losses and available supply and return pressures for each point. It lists all water cooled equipment, highlights the water cooled cables as the most demanding equipment followed by the radio frequency racks and cavities, and by the power converters. Their main cooling requirements and their positions in the tunnel are also presented.

Unstable fluid flow in a water-cooled heating channel

International Nuclear Information System (INIS)

Delayre, R.; Saunier, J.P.

1961-01-01

Experimental investigations of the instable behavior of a pressurized water flow in forced convection in a heating channel, with subcooled or bulk boiling have been carried. Tests were conducted at 1140, 850 and 570 psi. The test section was 35 in. high, surmounted by a 25.4 in. riser, these sections were by-passed by a pipe where the flow was between 1 and 4 times the flow in the test section. The water velocity (in the test section) was between 1.6 and 6.6 ft/s. Under certain conditions oscillations with a period of several seconds and perfectly stable have been observed. A mathematical model has been defined and a good agreement obtained for the main characteristics of the oscillations. It seems that the dimensions of the riser have a determining effect: the inception of bulk boiling gives an important variation of the driving head which can generate oscillations due to the non-zero delay for the system to reach its equilibrium. (author) [fr

Investigation of Cooling Water Injection into Supersonic Rocket Engine Exhaust

Science.gov (United States)

Jones, Hansen; Jeansonne, Christopher; Menon, Shyam

2017-11-01

Water spray cooling of the exhaust plume from a rocket undergoing static testing is critical in preventing thermal wear of the test stand structure, and suppressing the acoustic noise signature. A scaled test facility has been developed that utilizes non-intrusive diagnostic techniques including Focusing Color Schlieren (FCS) and Phase Doppler Particle Anemometry (PDPA) to examine the interaction of a pressure-fed water jet with a supersonic flow of compressed air. FCS is used to visually assess the interaction of the water jet with the strong density gradients in the supersonic air flow. PDPA is used in conjunction to gain statistical information regarding water droplet size and velocity as the jet is broken up. Measurement results, along with numerical simulations and jet penetration models are used to explain the observed phenomena. Following the cold flow testing campaign a scaled hybrid rocket engine will be constructed to continue tests in a combusting flow environment similar to that generated by the rocket engines tested at NASA facilities. LaSPACE.

Influence of flow on the synergistic effect of an inhibitive mixture used for water treatment in cooling circuits

International Nuclear Information System (INIS)

Ochoa, Nathalie; Pebere, Nadine; Moran, Francis; Tribollet, Bernard

2004-01-01

This work concerned an extensive study of the mechanism of inhibition of a carbon steel in a 200 mg l -1 NaCl solution by a non-toxic multicomponent inhibitor used for water treatment in cooling circuits. The inhibitive formulation was composed of 50 mg l -1 fatty amines associated with 200 mg l -1 phosphonocarboxylic acid salts. The influence of flow and immersion time was investigated by electrochemical impedance spectroscopy with a rotating disc electrode. The results were dependent on the experimental protocol used. Equivalent circuits were used to fit the experimental data. The properties of the protective layer were dependent on the electrode rotation rate and on the immersion time. This behaviour was related to the influence of flow on the anodic kinetics. (authors)

Technical analysis of a river basin-based model of advanced power plant cooling technologies for mitigating water management challenges

International Nuclear Information System (INIS)

Stillwell, Ashlynn S; Clayton, Mary E; Webber, Michael E

2011-01-01

Thermoelectric power plants require large volumes of water for cooling, which can introduce drought vulnerability and compete with other water needs. Alternative cooling technologies, such as cooling towers and hybrid wet-dry or dry cooling, present opportunities to reduce water diversions. This case study uses a custom, geographically resolved river basin-based model for eleven river basins in the state of Texas (the Brazos and San Jacinto-Brazos, Colorado and Colorado-Brazos, Cypress, Neches, Nueces, Red, Sabine, San Jacinto, and Trinity River basins), focusing on the Brazos River basin, to analyze water availability during drought. We utilized two existing water availability models for our analysis: (1) the full execution of water rights-a scenario where each water rights holder diverts the full permitted volume with zero return flow, and (2) current conditions-a scenario reflecting actual diversions with associated return flows. Our model results show that switching the cooling technologies at power plants in the eleven analyzed river basins to less water-intensive alternative designs can potentially reduce annual water diversions by 247-703 million m 3 -enough water for 1.3-3.6 million people annually. We consider these results in a geographic context using geographic information system tools and then analyze volume reliability, which is a policymaker's metric that indicates the percentage of total demand actually supplied over a given period. This geographic and volume reliability analysis serves as a measure of drought susceptibility in response to changes in thermoelectric cooling technologies. While these water diversion savings do not alleviate all reliability concerns, the additional streamflow from the use of dry cooling alleviates drought concerns for some municipal water rights holders and might also be sufficient to uphold instream flow requirements for important bays and estuaries on the Texas Gulf coast.

18 CFR 420.44 - Cooling water.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Cooling water. 420.44 Section 420.44 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.44 Cooling water. Water used...

Wall-cooling-induced mixed-convection flow recirculation in a vertical square-array multi-rod channel

International Nuclear Information System (INIS)

Luangdilok, W.; Todreas, N.E.

1989-01-01

This work investigated the structure of penetrative flow recirculation and associated flow conditions in a multi-rod channel induced by interassembly heat transfer that causes cooling through channel walls. Three investigation approaches, experimental, numerical, and analytical were employed in a complimentary fashion. Physical experiments involved water flow visualization and temperature measurement in a 4x4 rod square channel. Numerical experiments involved 3-dimensional simulations of water and sodium flow in a 2x2-rod channels. An approximate reverse flow model including Prandtl number effect was developed. A correlating equation based on the model and experiments was verified for water to correctly predict the trend of the 4x4-rod experimental penetration depth data. (orig.)

Study on dew point evaporative cooling system with counter-flow configuration

International Nuclear Information System (INIS)

Lin, J.; Thu, K.; Bui, T.D.; Wang, R.Z.; Ng, K.C.; Chua, K.J.

2016-01-01

Highlights: • Numerical model for a dew point evaporative cooler verified with experiments. • Saturation point of the working air is independent of the inlet air conditions. • The intensity of cooling capacity and water evaporation are studied. • The overall heat transfer coefficient for the working air is analyzed. • The conditions to achieve sub-wet bulb cooling are examined. - Abstract: Dew point evaporative cooling has great potential as a disruptive process for sensible cooling of air below its entering wet bulb temperature. This paper presents an improved mathematical model for a single-stage dew point evaporative cooler in a counter-flow configuration. Longitudinal heat conduction and mass diffusion of the air streams, channel plate and water film, as well as the temperature difference between the plate and water film, are accounted for in the model. Predictions of the product air temperature are validated using three sets of experimental data within a discrepancy of 4%. The cooler’s heat and mass transfer process is analyzed in terms of its cooling capacity intensity, water evaporation intensity, and overall heat transfer coefficient along the channel. Parametric studies are conducted at different geometric and operating conditions. For the conditions evaluated, the study reveals that (1) the saturation point of the working air occurs at a fixed point regardless of the inlet air conditions, and it is mainly influenced by the working air ratio and channel height; (2) the intensity of the water evaporation approaches a minimum at 0.2 to 0.3 m from the entrance; (3) the wet channel can be separated into two zones, and the overall heat transfer coefficient is above 100 W/(m"2·K) after the temperature of water film becomes higher than the working air temperature.

To cool, but not too cool: that is the question--immersion cooling for hyperthermia.

Science.gov (United States)

Taylor, Nigel A S; Caldwell, Joanne N; Van den Heuvel, Anne M J; Patterson, Mark J

2008-11-01

Patient cooling time can impact upon the prognosis of heat illness. Although ice-cold-water immersion will rapidly extract heat, access to ice or cold water may be limited in hot climates. Indeed, some have concerns regarding the sudden cold-water immersion of hyperthermic individuals, whereas others believe that cutaneous vasoconstriction may reduce convective heat transfer from the core. It was hypothesized that warmer immersion temperatures, which induce less powerful vasoconstriction, may still facilitate rapid cooling in hyperthermic individuals. Eight males participated in three trials and were heated to an esophageal temperature of 39.5 degrees C by exercising in the heat (36 degrees C, 50% relative humidity) while wearing a water-perfusion garment (40 degrees C). Subjects were cooled using each of the following methods: air (20-22 degrees C), cold-water immersion (14 degrees C), and temperate-water immersion (26 degrees C). The time to reach an esophageal temperature of 37.5 degrees C averaged 22.81 min (air), 2.16 min (cold), and 2.91 min (temperate). Whereas each of the between-trial comparisons was statistically significant (P < 0.05), cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45-s cooling time difference would have any meaningful physiological or clinical implications. It is assumed that this rapid heat loss was due to a less powerful peripheral vasoconstrictor response, with central heat being more rapidly transported to the skin surface for dissipation. Although the core-to-water thermal gradient was much smaller with temperate-water cooling, greater skin and deeper tissue blood flows would support a superior convective heat delivery. Thus, a sustained physiological mechanism (blood flow) appears to have countered a less powerful thermal gradient, resulting in clinically insignificant differences in heat extraction between the cold and temperate cooling trials.

Numerical analysis of heat and mass transfer for water recovery in an evaporative cooling tower

Science.gov (United States)

Lee, Hyunsub; Son, Gihun

2017-11-01

Numerical analysis is performed for water recovery in an evaporative cooling tower using a condensing heat exchanger, which consists of a humid air channel and an ambient dry air channel. The humid air including water vapor produced in an evaporative cooling tower is cooled by the ambient dry air so that the water vapor is condensed and recovered to the liquid water. The conservation equations of mass, momentum, energy and vapor concentration in each fluid region and the energy equation in a solid region are simultaneously solved with the heat and mass transfer boundary conditions coupled to the effect of condensation on the channel surface of humid air. The present computation demonstrates the condensed water film distribution on the humid air channel, which is caused by the vapor mass transfer between the humid air and the colder water film surface, which is coupled to the indirect heat exchange with the ambient air. Computations are carried out to predict water recovery rate in parallel, counter and cross-flow type heat exchangers. The effects of air flow rate and channel interval on the water recovery rate are quantified.

Comparative study of the performance of the M-cycle counter-flow and cross-flow heat exchangers for indirect evaporative cooling – Paving the path toward sustainable cooling of buildings

International Nuclear Information System (INIS)

Zhan, Changhong; Duan, Zhiyin; Zhao, Xudong; Smith, Stefan; Jin, Hong; Riffat, Saffa

2011-01-01

This paper provides a comparative study of the performance of cross-flow and counter-flow M-cycle heat exchangers for dew point cooling. It is recognised that evaporative cooling systems offer a low energy alternative to conventional air conditioning units. Recently emerged dew point cooling, as the renovated evaporative cooling configuration, is claimed to have much higher cooling output over the conventional evaporative modes owing to use of the M-cycle heat exchangers. Cross-flow and counter-flow heat exchangers, as the available structures for M-cycle dew point cooling processing, were theoretically and experimentally investigated to identify the difference in cooling effectiveness of both under the parallel structural/operational conditions, optimise the geometrical sizes of the exchangers and suggest their favourite operational conditions. Through development of a dedicated computer model and case-by-case experimental testing and validation, a parametric study of the cooling performance of the counter-flow and cross-flow heat exchangers was carried out. The results showed the counter-flow exchanger offered greater (around 20% higher) cooling capacity, as well as greater (15%–23% higher) dew-point and wet-bulb effectiveness when equal in physical size and under the same operating conditions. The cross-flow system, however, had a greater (10% higher) Energy Efficiency (COP). As the increased cooling effectiveness will lead to reduced air volume flow rate, smaller system size and lower cost, whilst the size and cost are the inherent barriers for use of dew point cooling as the alternation of the conventional cooling systems, the counter-flow system is considered to offer practical advantages over the cross-flow system that would aid the uptake of this low energy cooling alternative. In line with increased global demand for energy in cooling of building, largely by economic booming of emerging developing nations and recognised global warming, the research

Theoretical analysis of the performance of different cooling strategies with the concept of cool exergy

DEFF Research Database (Denmark)

Kazanci, Ongun Berk; Shukuya, Masanori; Olesen, Bjarne W.

2016-01-01

The whole chains of exergy flows for different cooling systems were compared. The effects of cooling demand (internal vs. external solar shading), space cooling method (floor cooling vs. air cooling with ventilation system), and the availability of a nearby natural heat sink (intake air for the v......The whole chains of exergy flows for different cooling systems were compared. The effects of cooling demand (internal vs. external solar shading), space cooling method (floor cooling vs. air cooling with ventilation system), and the availability of a nearby natural heat sink (intake air...... for the ventilation system being outdoor air vs. air from the crawl-space, and air-to-water heat pump vs. ground heat exchanger as cooling source) on system exergy performance were investigated. It is crucial to minimize the cooling demand because it is possible to use a wide range of heat sinks (ground, lake, sea......-water, etc.) and indoor terminal units, only with a minimized demand. The water-based floor cooling system performed better than the air-based cooling system; when an air-to-water heat pump was used as the cooling source, the required exergy input was 28% smaller for the floor cooling system. The auxiliary...

Effect of horizontal flow on the cooling of the moderator brick in the advanced gas-cooled reactor

International Nuclear Information System (INIS)

Ganesan, P.; He, S.; Hamad, F.; Gotts, J.

2011-01-01

The paper reports an investigation of the effect of the horizontal cross flow on the temperature of the moderator brick in UK Advanced Gas-cooled Reactor (AGR) using computational fluid dynamics (CFD) with a conjugate heat transfer model for the solid and fluid. The commercial software package of ANSYS Fluent is used for this purpose. The CFD model comprises the full axial length of one-half of a typical fuel channel (assuming symmetry) and part of neighbouring channels on either side. Two sets of simulations have been carried out, namely, one with cross flow and one without cross flow. The effect of cross flow has subsequently been derived by comparing the results from the two groups of simulations. The study shows that a small cross flow can have a significant effect on the cooling of the graphite brick, causing the peak temperature of the brick to reduce significantly. Two mechanisms are identified to be responsible for this. Firstly, the small cross flow causes a significant redistribution of the main axial downward flow and this leads to an enhancement of heat transfer in some of the small clearances, and an impairment in others although overall, the enhancement is dominant leading to a better cooling. Secondly, the cross flow makes effective use of the small clearances between the key/keyway connections which increases the effective heat transfer area, hence increasing the cooling. Under the conditions of no cross flow, these areas remain largely inactive in heat transfer. The study shows that the cooling of the moderator is significantly enhanced by the cross flow perpendicular to the main cooling flow. (author)

Analysis of Turbine Blade Relative Cooling Flow Factor Used in the Subroutine Coolit Based on Film Cooling Correlations

Science.gov (United States)

Schneider, Steven J.

2015-01-01

Heat transfer correlations of data on flat plates are used to explore the parameters in the Coolit program used for calculating the quantity of cooling air for controlling turbine blade temperature. Correlations for both convection and film cooling are explored for their relevance to predicting blade temperature as a function of a total cooling flow which is split between external film and internal convection flows. Similar trends to those in Coolit are predicted as a function of the percent of the total cooling flow that is in the film. The exceptions are that no film or 100 percent convection is predicted to not be able to control blade temperature, while leaving less than 25 percent of the cooling flow in the convection path results in nearing a limit on convection cooling as predicted by a thermal effectiveness parameter not presently used in Coolit.

Study on dew point evaporative cooling system with counter-flow configuration

KAUST Repository

Lin, J.

2015-12-18

Dew point evaporative cooling has great potential as a disruptive process for sensible cooling of air below its entering wet bulb temperature. This paper presents an improved mathematical model for a single-stage dew point evaporative cooler in a counter-flow configuration. Longitudinal heat conduction and mass diffusion of the air streams, channel plate and water film, as well as the temperature difference between the plate and water film, are accounted for in the model. Predictions of the product air temperature are validated using three sets of experimental data within a discrepancy of 4%. The cooler’s heat and mass transfer process is analyzed in terms of its cooling capacity intensity, water evaporation intensity, and overall heat transfer coefficient along the channel. Parametric studies are conducted at different geometric and operating conditions. For the conditions evaluated, the study reveals that (1) the saturation point of the working air occurs at a fixed point regardless of the inlet air conditions, and it is mainly influenced by the working air ratio and channel height; (2) the intensity of the water evaporation approaches a minimum at 0.2 to 0.3m from the entrance; (3) the wet channel can be separated into two zones, and the overall heat transfer coefficient is above 100W/(m2·K) after the temperature of water film becomes higher than the working air temperature.

Reducing water consumption of an industrial plant cooling unit using hybrid cooling tower

International Nuclear Information System (INIS)

Rezaei, Ebrahim; Shafiei, Sirous; Abdollahnezhad, Aydin

2010-01-01

Water consumption is an important problem in dry zones and poor water supply areas. For these areas use of a combination of wet and dry cooling towers (hybrid cooling) has been suggested in order to reduce water consumption. In this work, wet and dry sections of a hybrid cooling tower for the estimation of water loss was modeled. A computer code was also written to simulate such hybrid cooling tower. To test the result of this simulation, a pilot hybrid tower containing a wet tower and 12 compact air cooled heat exchangers was designed and constructed. Pilot data were compared with simulation data and a correction factor was added to the simulation. Ensuring that the simulation represents the actual data, it was applied to a real industrial case and the effect of using a dry tower on water loss reduction of this plant cooling unit was investigated. Finally feasibility study was carried out to choose the best operating conditions for the hybrid cooling tower configuration proposed for this cooling unit.

Ground water heat pumps and cooling with ground water basins as seasonal storage; Grundvandsvarmepumper og -koeling med grundvandsmagasiner som saesonlager

Energy Technology Data Exchange (ETDEWEB)

2008-04-15

Ground water temperature is constant all the year round, in Denmark approximately 9 deg. C, which is ideal for a number of cooling purposes including cooling of buildings. The structures in which the ground water flows (sand, gravel and chalk) are efficient for storing coldness and heat over longer periods. By using seasonal storage of low-temperature heat and coldness in ground water layers close to the terrain it is feasible to reach profitable energy savings of up to 90% for cooling and heating of e.g. hotels, airports, shopping malls, office buildings and other larger buildings. At the same time the large energy savings means major reduction of CO{sub 2} emissions. (BA)

Thermographic venous blood flow characterization with external cooling stimulation

Science.gov (United States)

Saxena, Ashish; Ng, E. Y. K.; Raman, Vignesh

2018-05-01

Experimental characterization of blood flow in a human forearm is done with the application of continuous external cooling based active thermography method. Qualitative and quantitative detection of the blood vessel in a thermal image is done, along with the evaluation of blood vessel diameter, blood flow direction, and velocity in the target blood vessel. Subtraction based image manipulation is performed to enhance the feature contrast of the thermal image acquired after the removal of external cooling. To demonstrate the effect of occlusion diseases (obstruction), an external cuff based occlusion is applied after the removal of cooling and its effect on the skin rewarming is studied. Using external cooling, a transit time method based blood flow velocity estimation is done. From the results obtained, it is evident that an external cooling based active thermography method can be used to develop a diagnosis tool for superficial blood vessel diseases.

A water-cooled 13-kG magnet system

International Nuclear Information System (INIS)

Rossi, J.O.; Goncalves, J.A.N.; Barroso, J.J.; Patire Junior, H.; Spassovsky, I.P.; Castro, P.J.

1993-01-01

The construction, performance, and reliability of a high field magnet system are reported. The magnet is designed to generate a flat top 13 kG magnetic induction required for the operation of a 35 GHz, 100 k W gyrotron under development at INPE. The system comprises three solenoids, located in the gun, cavity, and collector regions, consisting of split pair magnets with the field direction vertical. The magnets are wound from insulated copper tube whose rectangular cross section has 5.0 mm-diameter hole leading the cooling water. On account of the high power (∼ 100 k W) supplied to the cavity coils, it turned out necessary to employ a cooling system which includes hydraulic pump a heat exchanger. The collector and gun magnets operate at lower DC current (∼ 150 A), and, in this case, flowing water provided by wall pipes is far enough to cool down the coils. In addition, a 250 k V A high power AC/DC Nutek converser is used to supply power to the cavity magnet. For the collector and gun magnets, 30 V/600 A DC power supplies are used. (author)

A system for cooling electronic elements with an EHD coolant flow

International Nuclear Information System (INIS)

Tanski, M; Kocik, M; Barbucha, R; Garasz, K; Mizeraczyk, J; Kraśniewski, J; Oleksy, M; Hapka, A; Janke, W

2014-01-01

A system for cooling electronic components where the liquid coolant flow is forced with ion-drag type EHD micropumps was tested. For tests we used isopropyl alcohol as the coolant and CSD02060 diodes in TO-220 packages as cooled electronic elements. We have studied thermal characteristics of diodes cooled with EHD flow in the function of a coolant flow rate. The transient thermal impedance of the CSD02060 diode cooled with 1.5 ml/min EHD flow was 7.8°C/W. Similar transient thermal impedance can be achieved by applying to the diode a large RAD-A6405A/150 heat sink. We found out that EHD pumps can be successfully applied for cooling electronic elements.

Desalting a process cooling water using nanofiltration

NARCIS (Netherlands)

Radier, R.G.J.; van Oers, C.W.; Steenbergen, A.; Wessling, Matthias

2001-01-01

The cooling water system of a chemical plant of Akzo Nobel is a partly open system. The site is located at the North Sea. The air in contact with the cooling water contains seawater droplets dissolving and increasing the chloride concentration. The cooling water contains chromate to protect the

Hybrid radiator cooling system

Science.gov (United States)

France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

2016-03-15

A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

Air-cooled LiBr-water absorption chillers for solar air conditioning in extremely hot weathers

International Nuclear Information System (INIS)

Kim, D.S.; Infante Ferreira, C.A.

2009-01-01

A low temperature-driven absorption cycle is theoretically investigated for the development of an air-cooled LiBr-water absorption chiller to be combined with low-cost flat solar collectors for solar air conditioning in hot and dry regions. The cycle works with dilute LiBr-water solutions so that risk of LiBr crystallization is less than for commercially available water-cooled LiBr-water absorption chillers even in extremely hot ambient conditions. Two-phase heat exchangers in the system were modelled taking account of the heat and mass transfer resistances in falling film flows by applying the film theory in thermal and concentration boundary layers. Both directly and indirectly air-cooled chillers were modelled by properly combining component models and boundary conditions in a matrix system and solved with an algebraic equation solver. Simulation results predict that the chillers would deliver chilled water around 7.0 deg. C with a COP of 0.37 from 90 deg. C hot water under 35 deg. C ambient condition. At 50 deg. C ambient temperature, the chillers retained about 36% of their cooling power at 35 deg. C ambient. Compared with the directly air-cooled chiller, the indirectly air-cooled chiller presented a cooling power performance reduction of about 30%

Method of operating a water-cooled nuclear reactor

International Nuclear Information System (INIS)

Lysell, G.

1975-01-01

When operating a water-cooled nuclear reactor, in which the fuel rods consist of zirconium alloy tubes containing an oxidic nuclear fuel, stress corrosion in the tubes can be reduced or avoided if the power of the reactor is temporarily increased so much that the thermal expansion of the nuclear fuel produces a flow of the material in the tube. After that temporary power increase the power output is reduced to the normal power

Performance Analysis of Photovoltaic Panels with Earth Water Heat Exchanger Cooling

Directory of Open Access Journals (Sweden)

Jakhar Sanjeev

2016-01-01

Full Text Available The operating temperature is an important factor affecting the performance and life span of the Photovoltaic (PV panels. The rising temperature can be maintained within certain limit using proper cooling techniques. In the present research a novel system for cooling of PV panels named as Earth Water Heat Exchanger (EWHE is proposed and modelled in transient analysis simulation tool (TRNSYS v17.0 for the conditions of Pilani, Rajasthan (India.The various parameters which include cell temperature, PV power output and cell efficiency are observed with respect to variation in mass flow rate of fluid. Simulation results of the system without cooling show that the maximum PV panel temperature reached up to 79.31 °C with electrical efficiency dropped to 9% during peak sunshine hour. On the other hand, when PV panels are coupled with EWHE system, the panel temperature drops to 46.29 °C with an efficiency improving to 11% for a mass flow rate of 0.022 kg/s. In the end the cooling potential of EWHE is found to be in direct correlation with mass flow rate. The proposed system is very useful for the arid regions of western India which are blessed with high solar insolation throughout the year.

Water cooled static pressure probe

Science.gov (United States)

Lagen, Nicholas T. (Inventor); Eves, John W. (Inventor); Reece, Garland D. (Inventor); Geissinger, Steve L. (Inventor)

1991-01-01

An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

Emergency cooling of presurized water reactor

International Nuclear Information System (INIS)

Sykora, D.

1981-01-01

The method described of emergency core cooling in the pressurized water reactor is characterized by the fact that water is transported to the disturbed primary circuit or direct to the reactor by the action of the energy and mass of the steam and/or liquid phase of the secondary circuit coolant, which during emergency core cooling becomes an emergency cooling medium. (B.S.)

Effect of Thermoelectric Cooling (TEC module and the water flow heatsink on Photovoltaic (PV panel performance

Directory of Open Access Journals (Sweden)

Amelia A.R.

2017-01-01

Full Text Available Photovoltaic (PV panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

Science.gov (United States)

Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

2017-11-01

Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

Pitot tube and drag body measurements in transient steam--water flows

International Nuclear Information System (INIS)

Fincke, J.R.; Deason, V.A.; Dacus, M.W.

1979-01-01

The use of full-flow drag devices and rakes of water-cooled Pitot tubes to measure the transient two-phase mass flow during loss-of-coolant experiments in pressurized water reactor (PWR) environments has been developed. Mass flow rate measurements have been obtained in high temperature and pressure environments, similar to PWRs, under transient conditions. Comparisons of the measured time integrated value of mass flow to the known system mass before depressurization are made

Control-rod, pressure and flow-induced accident and transient analysis of a direct-cycle, supercritical-pressure, light-water-cooled fast breeder reactor

International Nuclear Information System (INIS)

Kitoh, Kazuaki; Koshizuka, Seiichi; Oka, Yoshiaki

1996-01-01

The features of the direct-cycle, supercritical-pressure, light-water-cooled fast breeder reactor (SCFBR) are high thermal efficiency and simple reactor system. The safety principle is basically the same as that of an LWR since it is a water-cooled reactor. Maintaining the core flow is the basic safety requirement of the reactor, since its coolant system is the one through type. The transient behaviors at control rod, pressure and flow-induced abnormalities are analyzed and presented in this paper. The results of flow-induced transients of SCFBR were reported at ICONE-3, though pressure change was neglected. The change of fuel temperature distribution is also considered for the analysis of the rapid reactivity-induced transients such as control rod withdrawal. Total loss of flow and pump seizure are analyzed as the accidents. Loss of load, control rod withdrawal from the normal operation, loss of feedwater heating, inadvertent start of an auxiliary feedwater pump, partial loss of coolant flow and loss of external power are analyzed as the transients. The behavior of the flow-induced transients is not so much different from the analyses assuming constant pressure. Fly wheels should be equipped with the feedwater pumps to prolong the coast-down time more than 10s and to cope with the total loss of flow accident. The coolant density coefficient of the SCFBR is less than one tenth of a BWR in which the recirculation flow is used for the power control. The over pressurization transients at the loss of load is not so severe as that of a BWR. The power reaches 120%. The minimum deterioration heat flux ratio (MDHFR) and the maximum pressure are sufficiently lower than the criteria; MDHFR above 1.0 and pressure ratio below 1.10 of 27.5 MPa, maximum pressure for operation. Among the reactivity abnormalities, the control rod withdrawal transient from the normal operation is analyzed

Modelling of flow and heat transfer in PV cooling channels

Energy Technology Data Exchange (ETDEWEB)

Diarra, D.C.; Harrison, S.J. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mechanical and Materials Engineering Solar Calorimetry Lab; Akuffo, F.O. [Kwame Nkrumah Univ. of Science and Technology, Kumasi (Ghana). Dept. of Mechanical Engineering

2005-07-01

Under sunny conditions, the temperature of photovoltaic (PV) modules can be 20 to 30 degrees C above the ambient air temperature. This affects the performance of PV modules, particularly in regions with hot climates. For silicon solar cells, the maximum power decreases between 0.4 and 0.5 per cent for every degree C of temperature increase above a reference value. In an effort to address this issue, this experimental and numerical study examined an active PV panel evaporative cooling scheme that is typically used in hot arid climates. The cooling system circulated cool air behind the PV modules, extracting heat and lowering solar cell temperature. A fluid dynamic and thermal model of the combined system was developed using the EES program in order to study the configuration of the cooling channel and the characteristics of the cooling flow. Heat transfer and flow characteristics in the cooling channel were then calculated along with pressure drop and fan power associated with the air-circulation. The net power output was also calculated. The objective was to design a cost efficient cooling system and to optimize its flow and pressure drop in order to maximize power output. The study demonstrated how the performance of the PV panel is influenced by the geometry of the cooling channel, the inlet air temperature and the air flow rate. 2 refs.

Application of two-phase flow for cooling of hybrid microchannel PV cells: A comparative study

International Nuclear Information System (INIS)

Valeh-e-Sheyda, Peyvand; Rahimi, Masoud; Karimi, Ebrahim; Asadi, Masomeh

2013-01-01

Highlights: ► Showing cooling potential of gas–liquid two-phase flow in microchannels for PV cell. ► Introducing the concept of using slug flow in microchannels for cooling of PV cells. ► In single-phase flow, increasing the liquid flow rate enhances the PV power. ► Showing that in two-phase flow the output power related the fluid flow regime. ► By coupling PV and microchannel an increase up to 38% in output power was observed. - Abstract: This paper reports the experimental data from performance of two-phase flows in a small hybrid microchannel solar cell. Using air and water as two-phase fluid, the experiments were conducted at indoor condition in an array of rectangular microchannels with a hydraulic diameter of 0.667 mm. The gas superficial velocity ranges were between 0 and 3.27 m s −1 while liquid flow rate was 0.04 m s −1 . The performance analysis of the PV cell at slug and transitional slug/annular flow regimes are the focus of this study. The influence of two-phase working fluid on PV cell cooling was compared with single-phase. In addition, the great potential of slug flow for heat removal enhancement in PV/T panel was investigated. The obtained data showed the proposed hybrid system could substantially increases the output power of PV solar cells

Models of steady state cooling flows in elliptical galaxies

International Nuclear Information System (INIS)

Vedder, P.W.; Trester, J.J.; Canizares, C.R.

1988-01-01

A comprehensive set of steady state models for spherically symmetric cooling flows in early-type galaxies is presented. It is found that a reduction of the supernova (SN) rate in ellipticals produces a decrease in the X-ray luminosity of galactic cooling flows and a steepening of the surface brightness profile. The mean X-ray temperature of the cooling flow is not affected noticeably by a change in the SN rate. The external pressure around a galaxy does not markedly change the luminosity of the gas within the galaxy but does change the mean temperature of the gas. The presence of a dark matter halo in a galaxy only changes the mean X-ray temperature slightly. The addition of a distribution of mass sinks which remove material from the general accretion flow reduces L(X) very slightly, flattens the surface brightness profile, and reduces the central surface brightness level to values close to those actually observed. A reduction in the stellar mass-loss rate only slightly reduces the X-ray luminosity of the cooling flow and flattens the surface brightness by a small amount. 37 references

Cooling water requirements and nuclear power plants

International Nuclear Information System (INIS)

Rao, T.S.

2010-01-01

Indian nuclear power programme is poised to scuttle the energy crisis of our time by proposing joint ventures for large power plants. Large fossil/nuclear power plants (NPPs) rely upon water for cooling and are therefore located near coastal areas. The amount of water a power station uses and consumes depends on the cooling technology used. Depending on the cooling technology utilized, per megawatt existing NPPs use and consume more water (by a factor of 1.25) than power stations using other fuel sources. In this context the distinction between 'use' and 'consume' of water is important. All power stations do consume some of the water they use; this is generally lost as evaporation. Cooling systems are basically of two types; Closed cycle and Once-through, of the two systems, the closed cycle uses about 2-3% of the water volumes used by the once-through system. Generally, water used for power plant cooling is chemically altered for purposes of extending the useful life of equipment and to ensure efficient operation. The used chemicals effluent will be added to the cooling water discharge. Thus water quality impacts on power plants vary significantly, from one electricity generating technology to another. In light of massive expansion of nuclear power programme there is a need to develop new ecofriendly cooling water technologies. Seawater cooling towers (SCT) could be a viable option for power plants. SCTs can be utilized with the proper selection of materials, coatings and can achieve long service life. Among the concerns raised about the development of a nuclear power industry, the amount of water consumed by nuclear power plants compared with other power stations is of relevance in light of the warming surface seawater temperatures. A 1000 MW power plant uses per day ∼800 ML/MW in once through cooling system; while SCT use 27 ML/MW. With the advent of new marine materials and concrete compositions SCT can be constructed for efficient operation. However, the

A water-cooled target of a 14 MeV neutron source

International Nuclear Information System (INIS)

Ogawa, Masuro; Seki, Masahiro; Kawamura, Hiroshi; Sanokawa, Konomo

1979-09-01

For the cooling system of a stationary target for the fusion neutronics source (FNS), designed to meet the structural, thermal and hydraulic requirements, thermohydraulic experiments were made. In the heat transfer experiment, in place of an accelerator, electric-heater assemblies were used. The relation of head loss and heat transfer was obtained as a function of Reynolds number. The head loss was not large for flow rates up to 1.3 l/s. Neither vibration of the apparatus nor cavitation of water was observed even at the maximum flow rate. The heat load of 1 kW for the beam diameter of 15mm, i.e. the requirement of FNS, could be removed by 0.2 l/s water flow, with the target-surface maximum temperature kept below 200 0 C. Extrapolation of the experimental results showed that with the target system, the maximum heat load is 2.3 kW for the beam of diameter 15 mm. The value is sufficiently large compared with the heat load of FNS; with finned cooling surfaces, the heat loads up to 3.7 kW may be removed. (author)

Behavior of cross flow heat exchangers during the cooling and dehumidification of air

Energy Technology Data Exchange (ETDEWEB)

Ober, C [Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Mess- und Regelungstechnik mit Maschinenlaboratorium

1980-09-01

The task of cross flow heat exchangers in room air engineering consists on the one hand in heating up the air and, on the other hand, in the simultaneous cooling and dehumidification. The facilities used for this purpose generally are multi-row finned pipe heat exchangers which when used for cooling contain cold water or brine as the working fluid. The use of directly evaporating freezing mixtures may not be included in this consideration. The model establishment for the dynamic and the static behavior of multi-row cross flow heat exchangers during cooling and dehumidification of air has been derived in this contribution. The representation is performed for the dynamic case in the complex, display range of the Laplace transformation. A comparison with experimental results can be done very simply by means of measurements of the frequency-responce curves in the form of Bode diagrams. The description of the static behaviour may be applied as a basis for humidity controls with more favourable energy utilization.

Flow directing means for air-cooled transformers

Science.gov (United States)

Jallouk, Philip A.

1977-01-01

This invention relates to improvements in systems for force-cooling transformers of the kind in which an outer helical winding and an insulation barrier nested therein form an axially extending annular passage for cooling-fluid flow. In one form of the invention a tubular shroud is positioned about the helical winding to define an axially extending annular chamber for cooling-fluid flow. The chamber has a width in the range of from about 4 to 25 times that of the axially extending passage. Two baffles extend inward from the shroud to define with the helical winding two annular flow channels having hydraulic diameters smaller than that of the chamber. The inlet to the chamber is designed with a hydraulic diameter approximating that of the coolant-entrance end of the above-mentioned annular passage. As so modified, transformers of the kind described can be operated at significantly higher load levels without exceeding safe operating temperatures. In some instances the invention permits continuous operation at 200% of the nameplate rating.

Design and analysis on super-critical water cooled power reactors

International Nuclear Information System (INIS)

Ishiwatari, Yuki

2005-01-01

The Super-Critical Water Cooled Power Reactors (SCPR) is cooled by 25 MPa supercritical water of 280degC at reactor inlet and greater than 500degC at reactor outlet and directly connected with turbine/generators with high energy conversion efficiency. This corresponds to the deletion of recirculation system and steam-water separation system of BWR type reactors or of pressurizer and steam generator of PWR type reactors. In addition to the design study of the university of Tokyo, technology development of the SCPR for practical use has started under the collaboration of industry and academia since 2000. Mockup single tube and bundle tests for heat transfer/fluid flow characteristics of the design have been conducted with 3D heat transfer analysis. Materials compatible with coolant conditions for fuel cans and reactor internals are also assessed. Overall evaluation of the reactor concept is under way. (T. Tanaka)

Cool-down flow-rate limits imposed by thermal stresses in LNG pipelines

Science.gov (United States)

Novak, J. K.; Edeskuty, F. J.; Bartlit, J. R.

Warm cryogenic pipelines are usually cooled to operating temperature by a small, steady flow of the liquid cryogen. If this flow rate is too high or too low, undesirable stresses will be produced. Low flow-rate limits based on avoidance of stratified two-phase flow were calculated for pipelines cooled with liquid hydrogen or nitrogen. High flow-rate limits for stainless steel and aluminum pipelines cooled by liquid hydrogen or nitrogen were determined by calculating thermal stress in thick components vs flow rate and then selecting some reasonable stress limits. The present work extends these calculations to pipelines made of AISI 304 stainless steel, 6061 aluminum, or ASTM A420 9% nickel steel cooled by liquid methane or a typical natural gas. Results indicate that aluminum and 9% nickel steel components can tolerate very high cool-down flow rates, based on not exceeding the material yield strength.

Free convection flow and heat transfer in pipe exposed to cooling

Energy Technology Data Exchange (ETDEWEB)

Mme, Uduak Akpan

2010-10-15

One of the challenges with thermal insulation design in subsea equipment is to minimize the heat loss through cold spots during production shut down. Cold spots are system components where insulation is difficult to implement, resulting in an insulation discontinuity which creates by nature a thermal bridge. It is difficult to avoid cold spots or thermal bridges in items like sensors, valves, connectors and supporting structures. These areas of reduced or no insulation are referred to as cold spots. Heat is drained faster through these spots, resulting in an increased local fluid density resulting in an internal fluid flow due to gravity and accelerated cool- down. This natural convection flow is important for both heat loss and internal distribution of the temperature. This thesis is presenting both experimental work and modelling work. A series of cool down tests and Computational Fluid Dynamics (CFD) simulations of these tests are presented. These tests and simulations were carried out in order to understand the flow physics involved in heat exchange processes caused by free convection flow in pipe exposed to cooling. Inclination of the pipe relative to the direction of gravity and temperature difference between cooling water and internal pipe water are the two main parameters investigated in this study. The experimental heat removal and temperature field is discussed and further interpreted by means of computational fluid dynamics. For prediction of the evolvement of the local temperature and heat flow, selection of an appropriate turbulence model is critical. Hence, different models and wall functions are investigated. The predicted temperature profiles and heat extraction rates are compered to the experiments for the selected turbulence models. Our main conclusions, supported by our experimental and CFD results, include: (i) Heat transfer from a localized cold spot in an inclined pipe is most efficient when the pipe orientation is close to horizontal. As the

The low-power low-pressure flow resonance in a natural circulation cooled boiling water reactor

Energy Technology Data Exchange (ETDEWEB)

Hagen, T.H.J.J. van der; Stekelenburg, A.J.C. [Delft Univ. of Technology (Netherlands)

1995-09-01

The last few years the possibility of flow resonances during the start-up phase of natural circulation cooled BWRs has been put forward by several authors. The present paper reports on actual oscillations observed at the Dodewaard reactor, the world`s only operating BWR cooled by natural circulation. In addition, results of a parameter study performed by means of a simple theoretical model are presented. The influence of relevant parameters on the resonance characteristics, being the decay ratio and the resonance frequency, is investigated and explained.

Storage of HLW in engineered structures: air-cooled and water-cooled concepts

International Nuclear Information System (INIS)

Ahner, S.; Dekais, J.J.; Puttke, B.; Staner, P.

1981-01-01

A comparative study on an air-cooled and a water-cooled intermediate storage of vitrified, highly radioactive waste (HLW) in overground installations has been performed by Nukem and Belgonucleaire respectively. In the air-cooled storage concept the decay heat from the storage area will be removed using natural convection. In the water-cooled storage concept the decay heat is carried off by a primary and secondary forced-cooling system with redundant and diverse devices. The safety study carried out by Nukem used a fault tree method. It shows that the reliability of the designed water-cooled system is very high and comparable to the inherent, safe, air-cooled system. The impact for both concepts on the environment is determined by the release route, but even during accident conditions the release is far below permissible limits. The economic analysis carried out by Belgonucleaire shows that the construction costs for both systems do not differ very much, but the operation and maintenance costs for the water-cooled facility are higher than for the air cooled facility. The result of the safety and economic analysis and the discussions with the members of the working group have shown some possible significant modifications for both systems, which are included in this report. The whole study has been carried out using certain national criteria which, in certain Member States at least, would lead to a higher standard of safety than can be justified on any social, political or economic grounds

Environmental and legal aspects of cooling water chemistry

International Nuclear Information System (INIS)

Hoffmann, H.J.

1988-01-01

The discharge and management of cooling water and waste water are subject to a number of ecological and legal requirements. For example, waste heat and cooling water constituents may affect surface bodies of water, or waste water discharge may have adverse effects on surface water and ground water. Waste water and cooling water discharge are subject to the Water Management Act (WHG) and the Waste Water Act, with about 50 administrative regulations. The requirements on water chemistry and analysis are gone into. (orig./HP) [de

Safety analysis of water cooled components inside the JET thermonuclear fusion tokamak

International Nuclear Information System (INIS)

Ageladarakis, P.; O'Dowd, N.; Papastergiou, S.

1998-04-01

The transient thermal behaviour of a number of components, installed in the vessel of the world's largest Fusion Tokamak (JET) has been examined with a theoretical model, which simulated normal operational conditions and abnormal scenarios namely: Loss of Coolant Flow; Loss of Torus Vacuum; and combinations. A number of theoretical results related to water and cryogenically cooled devices have been validated by a comprehensive experimental campaign conducted both inside the JET plasma chamber and in a test rig. The performance of water cooled components which may be subjected to boiling or freeze-up risks in case of a Loss of Water Flow event has also been analysed. Time constants of transient temperature changes were determined by the model while protective actions were prescribed in order to safeguard the equipment against associated risks. A completely automatic safety protection system has been designed on the basis of these analyses and implemented in the routine JET operation. During operation of JET the safety code reacted several times within the specified time limits and protected the relevant components during real off-normal events. (author)

Method of inhibiting concentration of radioactive corrosion products in cooling water or nuclear power plants

International Nuclear Information System (INIS)

Takabayashi, Jun-ichi; Hishida, Mamoru; Ishikura, Takeshi.

1979-01-01

Purpose: To suppress the increase in the concentration of the radioactive corrosion products in cooling water, which increase is accompanied by the transference of the corrosion products activated and accumulated in the core due to dissolution and exfoliation into the core water, and inhibit the flowing of said products out of the core and the diffusion thereof into the cooling system, thereby to prevent the accumulation of said products in the cooling system and prevent radioactive contaminations. Method: In a nuclear power plant of a BWR type light water reactor, when the temperature of the pile water is t 0 C, hydrogen is injected in cooling water in a period of time from immediately before starting of the drive stopping operation of the nuclear power plant to immediately after the termination of restarting operation, whereby the concentration of hydrogen in the reactor water through said period is maintained at a value more than 2exp (0.013 t) cm 3 N.T.P./kg H 2 O. (Aizawa, K.)

Comparison of solar panel cooling system by using dc brushless fan and dc water

International Nuclear Information System (INIS)

Irwan, Y M; Leow, W Z; Irwanto, M; M, Fareq; Hassan, S I S; Amelia, A R; Safwati, I

2015-01-01

The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer. (paper)

Analysis of BF Hearth Reasonable Cooling System Based on the Water Dynamic Characteristics

Science.gov (United States)

Zuo, Haibin; Jiao, Kexin; Zhang, Jianliang; Li, Qian; Wang, Cui

A rational cooling water system is the assurance for long campaign life of blast furnace. In the paper, the heat transfer of different furnace period and different furnace condition based on the water quality characteristics were analysed, and the reason of the heat flux over the normal from the hydrodynamics was analysed. The results showed that, the vapour-film and scale existence significantly influenced the hearth heat transfer, which accelerated the brick lining erosion. The water dynamic characteristics of the parallel inner pipe or among the pipes were the main reason for the abnormal heat flux and film boiling. As to the reasonable cooling water flow, the gas film and the scale should be controlled and the energy saving should be considered.

Nocturnal reverse flow in water-in-glass evacuated tube solar water heaters

International Nuclear Information System (INIS)

Tang, Runsheng; Yang, Yuqin

2014-01-01

Highlights: • Performance of water-in-glass evacuated tube solar water heaters (SWH) at night was studied. • Experimental measurements showed that reverse flow occurred in SWHs at night. • Reverse flow in SWHs was very high but the heat loss due to reverse flow was very low. • Reverse flow seemed not sensitive to atmospheric clearness but sensitive to collector tilt-angle. - Abstract: In this work, the thermal performance of water-in-glass evacuated tube solar water heaters (SWH) at nights was experimentally investigated. Measurements at nights showed that the water temperature in solar tubes was always lower than that in the water tank but higher than the ambient air temperature and T exp , the temperature of water inside tubes predicted in the case of the water in tubes being naturally cooled without reverse flow. This signified that the reverse flow in the system occurred at nights, making the water in solar tubes higher than T exp . It is found that the reverse flow rate in the SWH, estimated based on temperature measurements of water in solar tubes, seemed not sensitive to the atmospheric clearness but sensitive to the collector tilt-angle, the larger the tilt-angle of the collector, the higher the reverse flow rate. Experimental results also showed that, the reverse flow in the SWH was much higher as compared to that in a thermosyphonic domestic solar water heater with flat-plate collectors, but the heat loss from collectors to the air due to reverse flow in SWHs was very small and only took about 8–10% of total heat loss of systems

Low-pressure water-cooled inductively coupled plasma torch

Science.gov (United States)

Seliskar, Carl J.; Warner, David K.

1988-12-27

An inductively coupled plasma torch is provided which comprises an inner tube, including a sample injection port to which the sample to be tested is supplied and comprising an enlarged central portion in which the plasma flame is confined; an outer tube surrounding the inner tube and containing water therein for cooling the inner tube, the outer tube including a water inlet port to which water is supplied and a water outlet port spaced from the water inlet port and from which water is removed after flowing through the outer tube; and an r.f. induction coil for inducing the plasma in the gas passing into the tube through the sample injection port. The sample injection port comprises a capillary tube including a reduced diameter orifice, projecting into the lower end of the inner tube. The water inlet is located at the lower end of the outer tube and the r.f. heating coil is disposed around the outer tube above and adjacent to the water inlet.

Design and analysis of the DII-D radiative divertor water-cooled structures

International Nuclear Information System (INIS)

Hollerbach, M.A.; Smith, J.P.; Baxi, C.B.; Bozek; Chin, E.; Phelps, R.D.; Redler, K.M.; Reis, E.E.

1995-10-01

The Radiative Divertor is a major modification to the divertor of DIII-D and is being designed and fabricated for installation in late 1996. The Radiative Divertor Program (RDP) will enhance the dissipative processes in the edge and divertor plasmas to reduce the heat flux and plasma erosion at the divertor target. This approach will have major implications for the heat removal methods used in future devices. The divertor is of slot-type configuration designed to minimize the flow of sputtered and injected impurities back to the core plasma. The new divertor will be composed of toroidally continuous, Inconel 625 water-cooled rings of sandwich construction with an internal water channel, incorporating seam welding to provide the water-to-vacuum seal as well as structural integrity. The divertor structure is designed to withstand electromagnetic loads as a result of halo currents and induced toroidal currents. It also accommodates the thermal differences experienced during the 400 degrees C bake used on DIII-D. A low Z plasma-facing surface is provided by mechanically attached graphite tiles. Water flow through the rings will inertially cool these tiles which will be subjected to 38 MW, 10 second pulses. Current schedules call for detailed design in 1996 with installation completed in March 1997. A full size prototype, one-quarter of one ring, is being built to validate manufacturing techniques, machining, roll-forming, and seam welding. The experience and knowledge gained through the fabrication of the prototype is discussed. The design of the electrically isolated (5 kV) vacuum-to-air water feedthroughs supplying the water-cooled rings is also discussed

Design and analysis of the DIII-D radiative divertor water-cooled structures

International Nuclear Information System (INIS)

Hollerbach, M.A.; Smith, J.P.; Baxi, C.B.; Bozek, A.S.; Chin, E.; Phelps, R.D.; Redler, K.M.; Reis, E.E.

1995-01-01

The Radiative Divertor is a major modification to the divertor of DIII-D and is being designed and fabricated for installation in late 1996. The Radiative Divertor Program (RDP) will enhance the dissipative processes in the edge and divertor plasmas to reduce the heat flux and plasma erosion at the divertor target. This approach will have major implications for the heat removal methods used in future devices. The divertor is of slot-type configuration designed to minimize the flow of sputtered and injected impurities back to the core plasma. The new divertor will be composed of toroidally continuous, Inconel 625 water-cooled rings of sandwich construction with an internal water channel, incorporating seam welding to provide the water-to-vacuum seal as well as structural integrity. The divertor structure is designed to withstand electro-magnetic loads as a result of halo currents and induced toroidal currents. It also accommodates the thermal differences experienced during the 400 C bake used on DIII-D. A low Z plasma-facing surface is provided by mechanically attached graphite tiles. Water flow through the rings will inertially cool these tiles which will be subjected to 38 MW, 10 second pulses. Current schedules call for detailed design in 1996 with installation completed in March 1997. A full size prototype, one-quarter of one ring, is being built to validate manufacturing techniques, machining, roll-forming, and seam welding. The experience and knowledge gained through the fabrication of the prototype is discussed. The design of the electrically isolated (5 kV) vacuum-to-air water feedthroughs supplying the water-cooled rings is also discussed

Legionella confirmation in cooling tower water

Science.gov (United States)

Farhat, Maha; Shaheed, Raja A.; Al-Ali, Haidar H.; Al-Ghamdi, Abdullah S.; Al-Hamaqi, Ghadeer M.; Maan, Hawraa S.; Al-Mahfoodh, Zainab A.; Al-Seba, Hussain Z.

2018-01-01

Objectives: To investigate the presence of Legionella spp in cooling tower water. Legionella proliferation in cooling tower water has serious public health implications as it can be transmitted to humans via aerosols and cause Legionnaires’ disease. Methods: Samples of cooling tower water were collected from King Fahd Hospital of the University (KFHU) (Imam Abdulrahman Bin Faisal University, 2015/2016). The water samples were analyzed by a standard Legionella culture method, real-time polymerase chain reaction (RT-PCR), and 16S rRNA next-generation sequencing. In addition, the bacterial community composition was evaluated. Results: All samples were negative by conventional Legionella culture. In contrast, all water samples yielded positive results by real-time PCR (105 to 106 GU/L). The results of 16S rRNA next generation sequencing showed high similarity and reproducibility among the water samples. The majority of sequences were Alpha-, Beta-, and Gamma-proteobacteria, and Legionella was the predominant genus. The hydrogen-oxidizing gram-negative bacterium Hydrogenophaga was present at high abundance, indicating high metabolic activity. Sphingopyxis, which is known for its resistance to antimicrobials and as a pioneer in biofilm formation, was also detected. Conclusion: Our findings indicate that monitoring of Legionella in cooling tower water would be enhanced by use of both conventional culturing and molecular methods. PMID:29436561

A flow cryostat for cooling of eight independent pipe guns

DEFF Research Database (Denmark)

Sørensen, H.; Hansen, J.E.; Sass, B.

1991-01-01

A flow cryostat allowing independent cooling of eight pipe guns in a multishot deuterium pellet injector is described. The pipe guns are placed symmetrically around the flow cryostat and with a liquid helium consumption of 4-5 l/h the cooling is sufficient for simultaneous formation of eight...

The effect of cooling conditions on convective heat transfer and flow in a steam-cooled ribbed duct

International Nuclear Information System (INIS)

Shui, Linqi; Gao, Jianmin; Shi, Xiaojun; Liu, Jiazeng; Xu, Liang

2014-01-01

This work presents a numerical and experimental investigation on the heat transfer and turbulent flow of cooling steam in a rectangular duct with 90 .deg. ribs and studies the effect of cooling conditions on the heat transfer augmentation of steam. In the calculation, the variation range of Reynolds is from 10,000 to 190,000, the inlet temperature varies from 300 .deg. C to 500 .deg. C and the outlet pressure is from 0.5MPa to 6MPa. The aforementioned wide ranges of flow parameters cover the actual operating condition of coolant used in the gas turbine blades. The computations are carried with four turbulence models (the standard k-ε, the renormalized group (RNG) k-ε, the Launder-Reece-Rodi (LRR) and the Speziale-Sarkar-Gatski (SSG) turbulence models). The comparison of numerical and experimental results reveals that the SSG turbulence model is suitable for steam flow in the ribbed duct. Therefore, adopting the conjugate calculation technique, further study on the steam heat transfer and flow characteristics is performed with SSG turbulence model. The results show that the variation of cooling condition strongly impacts the forced convection heat transfer of steam in the ribbed duct. The cooling supply condition of a relative low temperature and medium pressure could bring a considerable advantage on steam thermal enhancement. In addition, comparing the heat transfer level between steam flow and air flow, the performance advantage of using steam is also influenced by the cooling supply condition. Changing Reynolds number has little effect on the performance superiority of steam cooling. Increasing pressure would strengthen the advantage, but increasing temperature gives an opposite result.

The effect of cooling conditions on convective heat transfer and flow in a steam-cooled ribbed duct

Energy Technology Data Exchange (ETDEWEB)

Shui, Linqi; Gao, Jianmin; Shi, Xiaojun; Liu, Jiazeng; Xu, Liang [Xi' an Jiaotong University, Xi' an (China)

2014-01-15

This work presents a numerical and experimental investigation on the heat transfer and turbulent flow of cooling steam in a rectangular duct with 90 .deg. ribs and studies the effect of cooling conditions on the heat transfer augmentation of steam. In the calculation, the variation range of Reynolds is from 10,000 to 190,000, the inlet temperature varies from 300 .deg. C to 500 .deg. C and the outlet pressure is from 0.5MPa to 6MPa. The aforementioned wide ranges of flow parameters cover the actual operating condition of coolant used in the gas turbine blades. The computations are carried with four turbulence models (the standard k-ε, the renormalized group (RNG) k-ε, the Launder-Reece-Rodi (LRR) and the Speziale-Sarkar-Gatski (SSG) turbulence models). The comparison of numerical and experimental results reveals that the SSG turbulence model is suitable for steam flow in the ribbed duct. Therefore, adopting the conjugate calculation technique, further study on the steam heat transfer and flow characteristics is performed with SSG turbulence model. The results show that the variation of cooling condition strongly impacts the forced convection heat transfer of steam in the ribbed duct. The cooling supply condition of a relative low temperature and medium pressure could bring a considerable advantage on steam thermal enhancement. In addition, comparing the heat transfer level between steam flow and air flow, the performance advantage of using steam is also influenced by the cooling supply condition. Changing Reynolds number has little effect on the performance superiority of steam cooling. Increasing pressure would strengthen the advantage, but increasing temperature gives an opposite result.

Cooling tower water ozonation at Southern University

International Nuclear Information System (INIS)

Chen, C.C.; Knecht, A.T.; Trahan, D.B.; Yaghi, H.M.; Jackson, G.H.; Coppenger, G.D.

1990-01-01

Cooling-tower water is a critical utility for many industries. In the past, inexpensive water coupled with moderate regulation of discharge water led to the neglect of the cooling tower as an energy resource. Now, with the increased cost of chemical treatment and tough EPA rules and regulations, this situation is rapidly changing. The operator of the DOE Y-12 Plant in Oak Ridge as well as many other industries are forced to develop an alternate method of water treatment. The cooling tower is one of the major elements in large energy systems. The savings accrued from a well engineered cooling tower can be a significant part of the overall energy conservation plan. During a short-term ozonation study between 1987-1988, the Y-12 Plant has been successful in eliminating the need for cooling tower treatment chemicals. However, the long-term impact was not available. Since April 1988, the ozone cooling water treatment study at the Y-12 Plant has been moved to the site at Southern University in Baton Rouge, Louisiana. The purpose of this continued study is to determine whether the use of ozonation on cooling towers is practical from an economic, technical and environmental standpoint. This paper discusses system design, operating parameter and performance testing of the ozonation system at Southern University

Core cooling system for reactor

International Nuclear Information System (INIS)

Kondo, Ryoichi; Amada, Tatsuo.

1976-01-01

Purpose: To improve the function of residual heat dissipation from the reactor core in case of emergency by providing a secondary cooling system flow channel, through which fluid having been subjected to heat exchange with the fluid flowing in a primary cooling system flow channel flows, with a core residual heat removal system in parallel with a main cooling system provided with a steam generator. Constitution: Heat generated in the core during normal reactor operation is transferred from a primary cooling system flow channel to a secondary cooling system flow channel through a main heat exchanger and then transferred through a steam generator to a water-steam system flow channel. In the event if removal of heat from the core by the main cooling system becomes impossible due to such cause as breakage of the duct line of the primary cooling system flow channel or a trouble in a primary cooling system pump, a flow control valve is opened, and steam generator inlet and outlet valves are closed, thus increasing the flow rate in the core residual heat removal system. Thereafter, a blower is started to cause dissipation of the core residual heat from the flow channel of a system for heat dissipation to atmosphere. (Seki, T.)

ISM stripping from cluster galaxies and inhomogeneities in cooling flows

Science.gov (United States)

Soker, Noam; Bregman, Joel N.; Sarazin, Craig L.

1990-01-01

Analyses of the x ray surface brightness profiles of cluster cooling flows suggest that the mass flow rate decreases towards the center of the cluster. It is often suggested that this decrease results from thermal instabilities, in which denser blobs of gas cool rapidly and drop below x ray emitting temperatures. If the seeds for the thermal instabilities are entropy perturbations, these perturbations must enter the flow already in the nonlinear regime. Otherwise, the blobs would take too long to cool. Here, researchers suggest that such nonlinear perturbations might start as blobs of interstellar gas which are stripped out of cluster galaxies. Assuming that most of the gas produced by stellar mass loss in cluster galaxies is stripped from the galaxies, the total rate of such stripping is roughly M sub Interstellar Matter (ISM) approx. 100 solar mass yr(-1). It is interesting that the typical rates of cooling in cluster cooling flows are M sub cool approx. 100 solar mass yr(-1). Thus, it is possible that a substantial portion of the cooling gas originates as blobs of interstellar gas stripped from galaxies. The magnetic fields within and outside of the low entropy perturbations can help to maintain their identities, both by suppressing thermal conduction and through the dynamical effects of magnetic tension. One significant question concerning this scenario is: Why are cooling flows seen only in a fraction of clusters, although one would expect gas stripping to be very common. It may be that the density perturbations only survive and cool efficiently in clusters with a very high intracluster gas density and with the focusing effect of a central dominant galaxy. Inhomogeneities in the intracluster medium caused by the stripping of interstellar gas from galaxies can have a number of other effects on clusters. For example, these density fluctuations may disrupt the propagation of radio jets through the intracluster gas, and this may be one mechanism for producing Wide

Electrochemistry of Water-Cooled Nuclear Reactors

International Nuclear Information System (INIS)

Dgiby Macdonald; Mirna Urquidi-Macdonald; John Mahaffy; Amit Jain Han Sang Kim; Vishisht Gupta; Jonathan Pitt

2006-01-01

This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a simulation tool to serve both as a training tool for plant operators and as an engineering test-bed to evaluate new equipment and operating strategies (normal operation, cold shut down and others). The development and implementation of the model allows us to estimate the activity transport or ''radiation fields'' around the primary loop and the vessel, as a function of the operating parameters and the water chemistry

Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower

Directory of Open Access Journals (Sweden)

Ahmadikia Hossein

2013-01-01

Full Text Available To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT, a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet phases. Comparison of the numerical results with one-dimensional analytical model and the experimental data illustrates a well-predicted heat transfer rate in the cooling tower. Applying water spray system on the cooling tower radiators enhances the cooling tower efficiency at both no wind and windy conditions. For all values of water spraying rate, NDDCTs operate most effectively at the crosswind velocity of 3m/s and as the wind speed continues to rise to more than 3 m/s up to 12 m/s, the tower efficiency will decrease by approximately 18%, based on no-wind condition. The heat transfer rate of radiator at wind velocity 10 m/s is 11.5% lower than that of the no wind condition. This value is 7.5% for water spray rate of 50kg/s.

Modification and application of water film model in COCOSYS for PWR's passive containment cooling

International Nuclear Information System (INIS)

Huang, Xi; Cheng, Xu

2014-01-01

Highlights: • Water film model in COCOSYS has been modified by considering film breakup. • Shear stress on film surface created by countercurrent flow has been considered. • Formation and development of rivulets have been taken into account. • Modified model has been applied for passive containment cooling system. • The modified water film model has optimized the simulation results. - Abstract: In this paper the physical model describing water film behaviors in German containment code system COCOSYS has been modified by taking into consideration the film breakup and subsequent phenomena as well as the effect of film interfacial shear stress created by countercurrent air flow. The modified model has extended its capability to predict particular water film behaviors including breakup at a critical film thickness based on minimum total energy criterion, the formation of rivulets according to total energy equilibrium as well as subsequent performance of rivulets according to several assumptions and observations from experiments. Furthermore, the modification considers also the change of velocity distribution on the cross section of film/rivulets due to shear stress. Based on the geometry of AP1000 and Generic Containment, simulations predicting containment pressure variation during accidents with operation of passive containment cooling system have been carried out. With the new model, considerably larger peak pressures are observed by comparing with those predicted with original water film model within a certain range of water film flow rate. Sensitivity analyses also point out that contact angle between water rivulets and steel substrate plays a significant role in the film cooling

Development of methods for the decrease in instability of recycling water of conjugated closed-circuit cooling system of HPP

Science.gov (United States)

Chichirov, A. A.; Chichirova, N. D.; Vlasov, S. M.; Lyapin, A. I.; Misbakhov, R. Sh.; Silov, I. Yu.; Murtazin, A. I.

2016-10-01

On Russian HPPs, conjugated closed-circuit cooling systems, where purge water is used as initial for water-treatment facilities, are widespread. For this reason, it is impossible to use general methods for the stabilization treatment of recycling water in order to prevent scale formation in the units of a system, namely, turbine condensers and cooling towers. In this paper, the methods for the decrease in the instability of recycling water using the methods of chemical engineering, such as stabilization and synchronization of flows and organization of recycles, are suggested. The results of an industrial experiment on the implementation of stabilization treatment of recycling water by the organization of recycle are given. The experiment was carried out on Kazan CHPP-3. The flow scheme involved the recycle of chemically purified water (CPW) for the heat network make-up to the closed-circuit cooling system. The experiment was carried out at three stages with the gradual change of the consumption of the recycle, namely, 0, 50, and 100 t/h. According to the results of experiments, the reliable decrease in the rate of the sedimentation was recorded on the units of the system, namely, turbine condenser and chimney-type cooling tower. This is caused by two reasons. Firstly, this is periodic excessive concentration of recycling water due to the nonstationary character of inlet and outlet flows. Secondly, this is seasonal (particularly, in the summer period) exceeding of the evaporation coefficient. As a result of stabilization and synchronization of flows and organization of recycles, the quality of clarified and chemically purified water for the heat network make-up increases and the corrosion of iron- and copper-containing structural materials decreases. A natural decrease in temperature drop on the operating turbine condensers is mentioned.

Emergency cooling system for a gas-cooled nuclear reactor

International Nuclear Information System (INIS)

Cook, R.K.; Burylo, P.S.

1975-01-01

The site of the gas-cooled reactor with direct-circuit gas turbine is preferably the sea coast. An emergency cooling system with safety valve and emergency feed-water addition is designed which affects at least a part of the reactor core coolant after leaving the core. The emergency cooling system includes a water emergency cooling circuit with heat exchanger for the core coolant. The safety valve releases water or steam from the emergency coolant circuit when a certain temperature is exceeded; this is, however, replaced by the emergency feed-water. If the gas turbine exhibits a high and low pressure turbine stage, which are flowed through by coolant one behind another, a part of the coolant can be removed in front of each part turbine by two valves and be added to the haet exchanger. (RW/LH) [de

Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

Energy Technology Data Exchange (ETDEWEB)

Jiang, J., E-mail: jiangjiaming@swip.ac.cn; Liu, Y.; Chen, Q.; Ji, X.Q.

2017-04-15

Highlights: • The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel. • Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model. • The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment. • The result shows water-cooling channel is good for the joule heat transfer and taken away. - Abstract: HL-2M in-vessel coils are positioned in high vacuum circumstance, and they will generate joule heat when they carry 15 kA electrical current, but joule heat is very difficult to dissipate in vacuum, so a hollow cable with 8 mm inner diameter is design as water-cooling channel for heat convection. By using the methods of the theoretical derivation, together with CFD numeric simulation method and the experiment of the heat transfer, the water channel of HL-2M in-vessel coils has been studied, and the temperature of HL-2M in-vessel coils under different cooling water flow rates is obtained and acceptable. Simultaneously, the external cooling water supply system parameters for the water-cooling channel of the coils are estimated. Three methods’ results are in good agreement; the theoretical model is verified and could be popularized for predicting the temperature rise of HL-2M in-vessel coils.

A novel approach for energy and water conservation in wet cooling towers by using MWNTs and nanoporous graphene nanofluids

International Nuclear Information System (INIS)

Askari, S.; Lotfi, R.; Seifkordi, A.; Rashidi, A.M.; Koolivand, H.

2016-01-01

Highlights: • Stable MWNTs and graphene nanofluids were used in a mechanical wet cooling tower. • Thermal and rheological properties of nanofluids were investigated. • Nanofluids enhanced the efficiency, cooling range and tower characteristic. • Water consumption reduced significantly for both MWNTs and graphene nanofluids. - Abstract: This study deals with an experimental investigation on the thermal performance of a mechanical wet cooling tower with counter flow arrangement by using multi-walled carbon nanotubes (MWNTs) and nanoporous graphene nanofluids. Stable nanofluids were prepared through two-step procedure by using water with properties taken from a working cooling tower in the South of Iran. Zeta potential revealed suitable stability of MWNTs and nanoporous graphene nanofluids. Thermal and rheological properties of the nanofluids were investigated. It was found that thermal conductivity increases by 20% and 16% at 45 °C for MWNTs and nanoporous graphene nanofluids, respectively. The increase in density and viscosity, particularly in low concentrations of nanoparticles, was insignificant enough for industrial applications. Moreover, it was found that by using nanofluids, efficiency, cooling range and tower characteristic (KaV/L) are enhanced in comparison to water. For instance, at inlet water temperature of 45 °C and water/air (L/G) flow ratio of 1.37, the cooling range increases by 40% and 67% for MWNTs and nanoporous graphene nanofluids (0.1 wt.%), respectively. On the other hand water consumption is reduces by 10% and 19% at inlet water temperature of 45 °C for MWNTs and nanoporous graphene nanofluids, respectively.

Analysis of tritium behaviour and recovery from a water-cooled Pb17Li blanket

International Nuclear Information System (INIS)

Malara, C.; Casini, G.; Viola, A.

1995-01-01

The question of the tritium recovery in water-cooled Pb17Li blankets has been under investigation for several years at JRC Ispra. The method which has been more extensively analysed is that of slowly circulating the breeder out from the blanket units and of extracting the tritium from it outside the plasma vacuum vessel by helium gas purging or vacuum degassing in a suited process apparatus. A computerized model of the tritium behaviour in the blanket units and in the extraction system was developed. It includes four submodels: (1) tritium permeation process from the breeder to the cooling water as a function of the local operative conditions (tritium concentration in Pb17Li, breeder temperature and flow rate); (2) tritium mass balance in each breeding unit; (3) tritium desorption from the breeder material to the gas phase of the extraction system; (4) tritium extraction efficiency as a function of the design parameters of the recovery apparatus. In the present paper, on the basis of this model, a parametric study of the tritium permeation rate in the cooling water and of the tritium inventory in the blanket is carried out. Results are reported and discussed in terms of dimensionless groups which describe the relative effects of the overall resistance on tritium transfer to the cooling water (with and without permeation barriers), circulating Pb17Li flow rate and extraction efficiency of the tritium recovery unit. The parametric study is extended to the recovery unit in the case of tritium extraction by helium purge or vacuum degassing in a droplet spray unit. (orig.)

Supercritical water natural circulation flow stability experiment research

Energy Technology Data Exchange (ETDEWEB)

Ma, Dongliang; Zhou, Tao; Li, Bing [North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; North China Electric Power Univ., Beijing (China). Inst. of Nuclear Thermalhydraulic Safety and Standardization; North China Electric Power Univ., Beijing (China). Beijing Key Lab. of Passive Safety Technology for Nuclear Energy; Huang, Yanping [Nuclear Power Institute of China, Chengdu (China). Science and Technology on Reactor System Design Technology Lab.

2017-12-15

The Thermal hydraulic characteristics of supercritical water natural circulation plays an important role in the safety of the Generation-IV supercritical water-cooled reactors. Hence it is crucial to conduct the natural circulation heat transfer experiment of supercritical water. The heat transfer characteristics have been studied under different system pressures in the natural circulation systems. Results show that the fluctuations in the subcritical flow rate (for natural circulation) is relatively small, as compared to the supercritical flow rate. By increasing the heating power, it is observed that the amplitude (and time period) of the fluctuation tends to become larger for the natural circulation of supercritical water. This tends to show the presence of flow instability in the supercritical water. It is possible to observe the flow instability phenomenon when the system pressure is suddenly reduced from the supercritical pressure state to the subcritical state. At the test outlet section, the temperature is prone to increase suddenly, whereas the blocking effect may be observed in the inlet section of the experiment.

Thermal-hydraulic evaluation study of the effectiveness of emergency core cooling system for light water reactors

International Nuclear Information System (INIS)

Sobajima, Makoto

1985-08-01

In order to evaluate the core cooling capability of the emergeny core cooling system, which is a safety guard system of light water reactors for a loss-of-coolant accident, a variety of large scale test were performed. Through the results, many phenomena were investigated and the predictabity of analytical codes were examined. The tests conducted were a single-vessel blowdown test, emergency core cooling test in a PWR simulation facility, spray cooling test for a BWR, large scale reflood test and a separate effect test on countercurrent flow. These test results were examined to clarify thermal-hydraulic phenomena and the effect of various test parameters and were utilized to improve predictability of the analytical codes. Some models for flow behavior in the upper core were also developed. By evaluating the effectiveness of various emergency core cooling system configurations, more effective cooling system than the current one was proposed and demonstrated. (author)

Control of fouling organisms in estuarine cooling water systems by chlorine and bromine chloride

International Nuclear Information System (INIS)

Burton, D.T.; Margrey, S.L.

1979-01-01

The study described was initiated to evaluate the antifouling effectiveness of chlorine and bromine chloride in low velocity flow areas where estuarine waters are used for cooling purposes. The relative antifouling effectiveness of chlorine and bromine chloride under intermittent and continuous modes of application in low velocity flow areas was evaluated at an estuarine power plant located on the Chesapeake Bay

Flow distribution analysis on the cooling tube network of ITER thermal shield

International Nuclear Information System (INIS)

Nam, Kwanwoo; Chung, Wooho; Noh, Chang Hyun; Kang, Dong Kwon; Kang, Kyoung-O; Ahn, Hee Jae; Lee, Hyeon Gon

2014-01-01

Thermal shield (TS) is to be installed between the vacuum vessel or the cryostat and the magnets in ITER tokamak to reduce the thermal radiation load to the magnets operating at 4.2K. The TS is cooled by pressurized helium gas at the inlet temperature of 80K. The cooling tube is welded on the TS panel surface and the composed flow network of the TS cooling tubes is complex. The flow rate in each panel should be matched to the thermal design value for effective radiation shielding. This paper presents one dimensional analysis on the flow distribution of cooling tube network for the ITER TS. The hydraulic cooling tube network is modeled by an electrical analogy. Only the cooling tube on the TS surface and its connecting pipe from the manifold are considered in the analysis model. Considering the frictional factor and the local loss in the cooling tube, the hydraulic resistance is expressed as a linear function with respect to mass flow rate. Sub-circuits in the TS are analyzed separately because each circuit is controlled by its own control valve independently. It is found that flow rates in some panels are insufficient compared with the design values. In order to improve the flow distribution, two kinds of design modifications are proposed. The first one is to connect the tubes of the adjacent panels. This will increase the resistance of the tube on the panel where the flow rate is excessive. The other design suggestion is that an orifice is installed at the exit of tube routing where the flow rate is to be reduced. The analysis for the design suggestions shows that the flow mal-distribution is improved significantly

Investigation of Water-spray Cooling of Turbine Blades in a Turbojet Engine

Science.gov (United States)

Freche, John C; Stelpflug, William J

1953-01-01

An analytical and experimental investigation was made with a J33-A-9 engine to determine the effectiveness of spray cooling as a means of increasing thrust by permitting engine operation at inlet-gas temperatures and speeds above rated. With the assumption of adequate spray cooling at a coolant-to-gas flow ratio of 3 percent, calculations for the sea-level static condition indicated a thrust may be achieved by engine operation at an inlet-gas temperature of 2000 degrees F and an overspeed of 10 percent. Of the water-injection configurations investigated experimentally, those located in the inner ring of the stator diaphragm provided the best cooling at rated engine speed.

Large-eddy simulation of open channel flow with surface cooling

International Nuclear Information System (INIS)

Walker, R.; Tejada-Martínez, A.E.; Martinat, G.; Grosch, C.E.

2014-01-01

Highlights: • Open channel flow comparable to a shallow tidal ocean flow is simulated using LES. • Unstable stratification is imposed by a constant surface cooling flux. • Full-depth, convection-driven, rotating supercells develop when cooling is applied. • Strengthening of cells occurs corresponding to an increasing of the Rayleigh number. - Abstract: Results are presented from large-eddy simulations of an unstably stratified open channel flow, driven by a uniform pressure gradient and with zero surface shear stress and a no-slip lower boundary. The unstable stratification is applied by a constant cooling flux at the surface and an adiabatic bottom wall, with a constant source term present to ensure the temperature reaches a statistically steady state. The structure of the turbulence and the turbulence statistics are analyzed with respect to the Rayleigh number (Ra τ ) representative of the surface buoyancy relative to shear. The impact of the surface cooling-induced buoyancy on mean and root mean square of velocity and temperature, budgets of turbulent kinetic energy (and components), Reynolds shear stress and vertical turbulent heat flux will be investigated. Additionally, colormaps of velocity fluctuations will aid the visualization of turbulent structures on both vertical and horizontal planes in the flow. Under neutrally stratified conditions the flow is characterized by weak, full-depth, streamwise cells similar to but less coherent than Couette cells in plane Couette flow. Increased Ra τ and thus increased buoyancy effects due to surface cooling lead to full-depth convection cells of significantly greater spanwise size and coherence, thus termed convective supercells. Full-depth convective cell structures of this magnitude are seen for the first time in this open channel domain, and may have important implications for turbulence analysis in a comparable tidally-driven ocean boundary layer. As such, these results motivate further study of the

A design study of high electric power for fast reactor cooled by supercritical light water

International Nuclear Information System (INIS)

Koshizuka, Seiichi

2000-03-01

In order to evaluate the possibility to achieve high electric power by a fast reactor with supercritical light water, the design study was carried out on a large fast reactor core with high coolant outlet temperature (SCFR-H). Since the reactor coolant circuit uses once-through direct cycle where all feedwater flows through the core to the turbine at supercritical pressure, it is possible to design much simpler and more compact reactor systems and to achieve higher thermal efficiency than those of current light water reactors. The once-through direct cycle system is employed in current fossil-fired power plants. In the present study, three types of core were designed. The first is SCFR-H with blankets cooled by ascending flow, the second is SCFR-H with blankets cooled by descending flow and the third is SCFR-H with high thermal power. Every core was designed to achieve the thermal efficiency over 43%, positive coolant density reactivity coefficient and electric power over 1600 MW. Core characteristics of SCFR-Hs were compared with those of SCLWR-H (electric power: 1212 MW), which is a thermal neutron spectrum reactor cooled and moderated by supercritical light water, with the same diameter of the reactor pressure vessel. It was shown that SCFR-H could increase the electric power about 1.7 times maximally. From the standpoint of the increase of a reactor thermal power, a fast reactor has advantages as compared with a thermal neutron reactor, because it can increase the power density by adopting tight fuel lattices and eliminating the moderator region. Thus, it was concluded that a reactor cooled by supercritical light water could further improve the cost competitiveness by using a fast neutron spectrum and achieving a higher thermal power. (author)

Operational cost minimization in cooling water systems

Directory of Open Access Journals (Sweden)

Castro M.M.

2000-01-01

Full Text Available In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.

Materials for advanced water cooled reactors

International Nuclear Information System (INIS)

1992-09-01

The current IAEA programme in advanced nuclear power technology promotes technical information exchange between Member States with major development programmes. The International Working Group on Advanced Technologies for Water Cooled Reactors recommended to organize a Technical Committee Meeting for the purpose of providing an international forum for technical specialists to review and discuss aspects regarding development trends in material application for advanced water cooled reactors. The experience gained from the operation of current water cooled reactors, and results from related research and development programmes, should be the basis for future improvements of material properties and applications. This meeting enabled specialists to exchange knowledge about structural materials application in the nuclear island for the next generation of nuclear power plants. Refs, figs, tabs

An experimental study on the cathode humidification and evaporative cooling of polymer electrolyte membrane fuel cells using direct water injection method at high current densities

International Nuclear Information System (INIS)

Hwang, Seong Hoon; Kim, Min Soo

2016-01-01

Highlights: • Proposal of a cathode humidification and evaporative cooling system for PEM fuel cells. • An external-mixing air-assist atomizer is used to produce a very fine water spray. • The system is effective in both cathode humidification and stack cooling. • Increased water flow rate improves stack performance and evaporative cooling capacity. • At a given water flow rate, lower stack temperatures cause greater humidification effect. - Abstract: Humidification and cooling are critical issues in enhancing the efficiency and durability of polymer electrolyte membrane fuel cells (PEMFCs). However, existing humidifiers and cooling systems have the disadvantage that they must be quite large to achieve adequate PEMFC performance. In this study, to eliminate the need for a bulky humidifier and to lighten the cooling load of PEMFCs, a cathode humidification and evaporative cooling system using an external-mixing air-assist atomizer was developed and its performance was investigated. The atomization performance of the nozzle was analyzed experimentally under various operating conditions with minimal changes in the system design. Experiments with a five-cell PEMFC stack with an active area of 250 cm"2 were carried out to analyze the effects of various parameters (such as the operating temperature, current density, and water injection flow rate) on the evaporation of injected water for humidification and cooling performances. The experimental results demonstrate that the direct water injection method proposed in this study is quite effective in cathode humidification and stack cooling in PEM fuel cells at high current densities. The stack performance was improved by humidification effect and the coolant temperature at the stack outlet decreased by evaporative cooling effect.

Pliocene cooling enhanced by flow of low-salinity Bering Sea water to the Arctic Ocean.

Science.gov (United States)

Horikawa, Keiji; Martin, Ellen E; Basak, Chandranath; Onodera, Jonaotaro; Seki, Osamu; Sakamoto, Tatsuhiko; Ikehara, Minoru; Sakai, Saburo; Kawamura, Kimitaka

2015-06-29

Warming of high northern latitudes in the Pliocene (5.33-2.58 Myr ago) has been linked to the closure of the Central American Seaway and intensification of North Atlantic Deep Water. Subsequent cooling in the late Pliocene may be related to the effects of freshwater input from the Arctic Ocean via the Bering Strait, disrupting North Atlantic Deep Water formation and enhancing sea ice formation. However, the timing of Arctic freshening has not been defined. Here we present neodymium and lead isotope records of detrital sediment from the Bering Sea for the past 4.3 million years. Isotopic data suggest the presence of Alaskan glaciers as far back as 4.2 Myr ago, while diatom and C37:4 alkenone records show a long-term trend towards colder and fresher water in the Bering Sea beginning with the M2 glaciation (3.3 Myr ago). We argue that the introduction of low-salinity Bering Sea water to the Arctic Ocean by 3.3 Myr ago preconditioned the climate system for global cooling.

Comprehensive study of flow and heat transfer at the surface of circular cooling fin

Science.gov (United States)

Mityakov, V. Yu; Grekov, M. A.; Gusakov, A. A.; Sapozhnikov, S. Z.; Seroshtanov, V. V.; Bashkatov, A. V.; Dymkin, A. N.; Pavlov, A. V.; Milto, O. A.; Kalmykov, K. S.

2017-11-01

For the first time is proposed to combine heat flux measurements with thermal imaging and PIV (particle image velocimetry) for a comprehensive study of flow and heat transfer at the surface of the circular cooling fin. The investigated hollow fin is heated from within with saturated water steam; meanwhile the isothermal external surface simulates one of the perfect fin. Flow and heat transfer at the surface of the solid fin of the same size and shape, made of titanium alloy is investigated in the same regimes. Gradient Heat Flux Sensors (GHFS) were installed at different places of the fin surface. Velocity field around a cylinder, temperature field at the surface of the fin and heat flux for each rated time were obtained. Comprehensive method including heat flux measurement, PIV and thermal imaging allow to study flow and heat transfer at the surface of the fin in real time regime. The possibility to study flow and heat transfer for non-isothermal fins is shown; it is allow to improve traditional calculation of the cooling fins.

Effect of ribbed and smooth coolant cross-flow channel on film cooling

International Nuclear Information System (INIS)

Peng, Wei; Sun, Xiaokai; Jiang, Peixue; Wang, Jie

2017-01-01

Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

Effect of ribbed and smooth coolant cross-flow channel on film cooling

Energy Technology Data Exchange (ETDEWEB)

Peng, Wei; Sun, Xiaokai [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China); Jiang, Peixue, E-mail: jiangpx@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Educations, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Wang, Jie [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China)

2017-05-15

Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

Skin cooling maintains cerebral blood flow velocity and orthostatic tolerance during tilting in heated humans

Science.gov (United States)

Wilson, Thad E.; Cui, Jian; Zhang, Rong; Witkowski, Sarah; Crandall, Craig G.

2002-01-01

Orthostatic tolerance is reduced in the heat-stressed human. The purpose of this project was to identify whether skin-surface cooling improves orthostatic tolerance. Nine subjects were exposed to 10 min of 60 degrees head-up tilting in each of four conditions: normothermia (NT-tilt), heat stress (HT-tilt), normothermia plus skin-surface cooling 1 min before and throughout tilting (NT-tilt(cool)), and heat stress plus skin-surface cooling 1 min before and throughout tilting (HT-tilt(cool)). Heating and cooling were accomplished by perfusing 46 and 15 degrees C water, respectively, though a tube-lined suit worn by each subject. During HT-tilt, four of nine subjects developed presyncopal symptoms resulting in the termination of the tilt test. In contrast, no subject experienced presyncopal symptoms during NT-tilt, NT-tilt(cool), or HT-tilt(cool). During the HT-tilt procedure, mean arterial blood pressure (MAP) and cerebral blood flow velocity (CBFV) decreased. However, during HT-tilt(cool), MAP, total peripheral resistance, and CBFV were significantly greater relative to HT-tilt (all P heat-stressed humans.

Method of injecting cooling water in emergency core cooling system (ECCS) of PWR type reactor

International Nuclear Information System (INIS)

Sobajima, Makoto; Adachi, Michihiro; Tasaka, Kanji; Suzuki, Mitsuhiro.

1979-01-01

Purpose: To provide a cooling water injection method in an ECCS, which can perform effective cooling of the reactor core. Method: In a method of injecting cooling water in an ECCS as a countermeasure against a rupture accident of a pwr type reactor, cooling water in the first pressure storage injection system is injected into the upper plenum of the reactor pressure vessel at a set pressure of from 50 to 90 atg. and a set temperature of from 80 to 200 0 C, cooling water in the second pressure storage injection system is injected into the lower plenum of the reactor pressure vessel at a pressure of from 25 to 60 atg. which is lower than the set pressure and a temperature less than 60 0 C, and further in combination with these procedures, cooling water of less than 60 0 C is injected into a high-temperature side piping, in the high-pressure injection system of upstroke of 100 atg. by means of a pump and the low-pressure injection system of upstroke of 20 atg. also by means of a pump, thereby cooling the reactor core. (Aizawa, K.)

WGOTHIC analysis of AP1000 passive containment cooling water

International Nuclear Information System (INIS)

Ye Cheng; Wang Yong; Zheng Mingguang; Wang Guodong; Zhang Di; Ni Chenxiao; Wang Minglu

2013-01-01

The WGOTHIC code was used to analyze the influence of the containment cooling water inventory to containment safety for different cases. The results show that if passive containment cooling system fails, the pressure in containment is beyond design limit after 1000 s; if cooling water can't be supplied after 72 h, the pressure in containment is beyond design limit after 0.9 d; if cooling water can't be supplied after 19.6 d, the pressure in containment is beyond design limit but less than the breakdown pressure; if cooling water is supplied for 30 d, the air cooling can remove the decay heat without any aid. It is a reference for making emergency plan and improving containment design. (authors)

HAZOP-study on heavy water research reactor primary cooling system

International Nuclear Information System (INIS)

Hashemi-Tilehnoee, M.; Pazirandeh, A.; Tashakor, S.

2010-01-01

By knowledge-based Hazard and Operability (HAZOP) technique, equipment malfunction and deficiencies in the primary cooling system of the generic heavy water research reactor are studied. This technique is used to identify the representative accident scenarios. The related Process Flow Drawing (PFD) is prepared as our study database for this plant. Since this facility is in the design stage, applying the results of HAZOP-study to PFD improves the safety of the plant.

Deuterium- and 18O-content in the cooling water of power station cooling towers

International Nuclear Information System (INIS)

Heimbach, H.; Dongmann, G.

1976-09-01

The 0-18/0-16 and D/H isotope ratios of water from two different cooling towers were determined by mass spectrometry. The observed isotope fractionation corresponds to that known from natural evaporation or transpiration processes: cooling tower I: delta(D) = 46.8 per thousand, delta( 18 O) = 7.6 per thousand cooling tower II: delta(D) = 33.9 per thousand delta( 18 O) = 5.7 per thousand Evaluation of simple compartment models of a cooling tower and a distillation device suggests that there exists some isotope discrimination within the open trickling unit of a cooling tower analogous to that in a rectification column. In a real cooling tower, however, this effect is compensated largely by the recycling of the cooling water, resulting only in a small enrichment of the heavy isotopes. This can be understood as the result of three partial effects: 1) a fractionation in the vapor pressure equilibrium, 2) a kinetic effect due to diffusion of the water vapor into a turbulent atmosphere, and 3) an exchange effect which is proportional to relative humidity. This low enrichment of the heavy isotope excludes the technical use of cooling towers as isotope separation devices. (orig.) [de

Simulation of solar lithium bromide-water absorption cooling system with parabolic trough collector

International Nuclear Information System (INIS)

Mazloumi, M.; Naghashzadegan, M.; Javaherdeh, K.

2008-01-01

Ahwaz is one of the sweltering cities in Iran where an enormous amount of energy is being consumed to cool residential places in a year. The aim of this research is to simulate a solar single effect lithium bromide-water absorption cooling system in Ahwaz. The solar energy is absorbed by a horizontal N-S parabolic trough collector and stored in an insulated thermal storage tank. The system has been designed to supply the cooling load of a typical house where the cooling load peak is about 17.5 kW (5 tons of refrigeration), which occurs in July. A thermodynamic model has been used to simulate the absorption cycle. The working fluid is water, which is pumped directly to the collector. The results showed that the collector mass flow rate has a negligible effect on the minimum required collector area, but it has a significant effect on the optimum capacity of the storage tank. The minimum required collector area was about 57.6 m 2 , which could supply the cooling loads for the sunshine hours of the design day for July. The operation of the system has also been considered after sunset by saving solar energy

Polymeric Materials For Scale Inhibition In Cooling Water Systems

Directory of Open Access Journals (Sweden)

Najwa S.Majeed

2013-04-01

Full Text Available Calcium carbonate deposition is generally predominant in cooling water-circulating system. For the control of calcium carbonate scale formation two types of polymeric scale inhibitors were used Polyamino polyether methylene phosphonate  (PAPEMPand polyacrylaminde(PAA.Model of cooling tower system have been built up in laboratory scale. Experiments were carried out using different inhibitor concentrations(0.5,1,1.5,2,3ppm ,at water temperature of  40oC and flow rate of 150 l/hr. It was found that Polyamino polyether methylene phosphonate    more effective than polyacryle amide'  as scale inhibitor in all used concentrations and the best inhibition efficiency (95% was at (2.5ppm of Polyamino polyether methylene phosphonate  and (85% with poly acryle amide at concentrations of (3 ppm. The performance of the polymeric scale inhibitors was compared with a method used to control heavy calcium carbonate scale forming by the deposition of sufficiently thin protective calcium carbonate scale using sulfuric acid and depending on Ryznar stability index controlling method. 

Electrochemical filtration for turbidity removal in industrial cooling/process water systems

International Nuclear Information System (INIS)

Kumbhar, A.G.; Venkateswaran, G.

2008-01-01

Water samples of large cooling water reservoirs may look visibly clear and transparent, but still may contain sub-micron size particles at sub-parts-per-million levels. Deposition of these particles on heat exchanger surfaces, reduces the heat transfer efficiency in power industry. In nuclear power plants, additionally it creates radiation exposure problems due to activation of fine metallic turbidity in the reactor core and its subsequent transfer to out-of-core surfaces. Sub-micron filtration creates back high-pressure problem. Zeta filters available commercially are prescribed for separating either positively or negatively charged particles. They are of once-use and throw-type. Precipitation surface modified ion exchangers impart chemical impurities to the system. Thus, sub-micron size and dilute turbidity removal from large volumes of waters such as heat exchanger cooling water in nuclear and power industry poses a problem. Electro deposition of the turbidity causing particles, on porous carbon/graphite felt electrodes, is one of the best suited methods for turbidity removal from large volumes of water due to the filter's high permeability, inertness to the system and regenerability resulting in low waste generation. Initially, active indium turbidity removal from RAPS-1 heavy water moderator system, and microbes removal from heat exchanger cooling lake water of RAPS 1 and 2 were demonstrated with in-house designed and fabricated prototype electrochemical filter (ECF). Subsequently, a larger size, high flow filter was fabricated and deployed for iron turbidity removal from active process waters system of Kaiga Generation Station unit 1 and silica and iron turbidity removal from cooling water pond used for heat exchanger of a high temperature high pressure (HTHP) loop at WSCD, Kalpakkam. The ECF proved its exclusive utility for sub-micron size turbidity removal and microbes removal. ECF maneuverability with potential and current for both positively and

The study on the evaporation cooling efficiency and effectiveness of cooling tower of film type

International Nuclear Information System (INIS)

Li Yingjian; You Xinkui; Qiu Qi; Li Jiezhi

2011-01-01

Based on heat and mass transport mechanism of film type cooling, which was combined with an on-site test on counter flow film type cooling tower, a mathematical model on the evaporation and cooling efficiency and effectiveness has been developed. Under typical climatic conditions, air conditioning load and the operating condition, the mass and heat balances have been calculated for the air and the cooling water including the volume of evaporative cooling water. Changing rule has been measured and calculated between coefficient of performance (COP) and chiller load. The influences of air and cooling water parameters on the evaporative cooling efficiency were analyzed in cooling tower restrained by latent heat evaporative cooling, and detailed derivation and computation revealed that both the evaporative cooling efficiency and effectiveness of cooling tower are the same characteristics parameters of the thermal performance of a cooling tower under identical assumptions.

Evaluation method of corrosive conditions in cooling systems of nuclear power plants by combined analyses of flow dynamics and corrosion

Energy Technology Data Exchange (ETDEWEB)

Uchida, Shunsuke [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Atomic Energy Society of Japan (AESJ) (Japan). Research Committee on Water Chemistry Standard; Naitoh, Masanori [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Atomic Energy Society of Japan (AESJ) (Japan). Computational Science and Engineering Div.; Uehara, Yasushi; Okada, Hidetoshi [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Hotta, Koji [ITOCHU Techno-Solutions Corporation (Japan); Ichikawa, Ryoko [Mizuho Information and Research Inst., Inc. (Japan); Koshizuka, Seiichi [Tokyo Univ. (Japan)

2007-03-15

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration, corrosion and their overlapping effects. In order to establish safe and reliable plant operation, it is necessary to predict future problems for structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious issues for plant operation. The analysis models are divided into two types. 1. Prediction models for future problems with structural materials: Distributions of oxidant concentrations along flow paths are obtained by solving water radiolysis reactions in the boiling water reactor (BWR) primary cooling water and hydrazine-oxygen reactions in the pressurized water reactor (PWR) secondary cooling water. Then, the electrochemical corrosion potential (ECP) at the point of interest is also obtained by the mixed potential model using oxidant concentration. Higher ECP enhances the possibility of intergranular stress corrosion cracking (IGSCC) in the BWR primary system, while lower ECP enhances flow accelerated corrosion (FAC) in the PWR secondary system. 2. Evaluation models of wall thinning caused by flow accelerated corrosion: The degree of wall thinning is evaluated at a location with a higher possibility of FAC occurrence, and lifetime is estimated for preventive maintenance. General features of models are reviewed in this paper and the prediction models for oxidant concentrations are briefly introduced. (orig.)

Evaluation method of corrosive conditions in cooling systems of nuclear power plants by combined analyses of flow dynamics and corrosion

International Nuclear Information System (INIS)

Uchida, Shunsuke; Hotta, Koji; Ichikawa, Ryoko; Koshizuka, Seiichi

2007-01-01

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration, corrosion and their overlapping effects. In order to establish safe and reliable plant operation, it is necessary to predict future problems for structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious issues for plant operation. The analysis models are divided into two types. 1. Prediction models for future problems with structural materials: Distributions of oxidant concentrations along flow paths are obtained by solving water radiolysis reactions in the boiling water reactor (BWR) primary cooling water and hydrazine-oxygen reactions in the pressurized water reactor (PWR) secondary cooling water. Then, the electrochemical corrosion potential (ECP) at the point of interest is also obtained by the mixed potential model using oxidant concentration. Higher ECP enhances the possibility of intergranular stress corrosion cracking (IGSCC) in the BWR primary system, while lower ECP enhances flow accelerated corrosion (FAC) in the PWR secondary system. 2. Evaluation models of wall thinning caused by flow accelerated corrosion: The degree of wall thinning is evaluated at a location with a higher possibility of FAC occurrence, and lifetime is estimated for preventive maintenance. General features of models are reviewed in this paper and the prediction models for oxidant concentrations are briefly introduced. (orig.)

Safety analysis for K reactor and impact of cooling tower installation

International Nuclear Information System (INIS)

Fields, C.C.; Wooten, L.A.; Geeting, M.W.; Morgan, C.E.; Buczek, J.A.; Smith, D.C.

1993-01-01

This paper describes the safety analysis of the Savannah River site K-reactor loss-of-cooling-water-supply (LOCWS) event and the impact on the analysis of a natural-draft cooling tower, which was installed in 1992. Historically (1954 to 1992), the K-reactor secondary cooling system [called the cooling water system (CWS)] used water from the Savannah River pumped to a 25-million-gal basin adjacent to the reactor. Approximately 170 000 gal/min were pumped from the basin through heat exchangers to remove heat from the primary cooling system. This water then entered a smaller basin, where it flowed over a weir and eventually returned to the Savannah River. The 25-million-gal basin is at a higher elevation than the heat exchangers and the smaller basin to supply cooling by gravity flow (which is sufficient to remove decay heat) if power to the CWS pumps is interrupted. Small amounts of cooling water are also used for other essential equipment such as diesels, motors, and oil coolers. With the cooling tower installed, ∼85% of the cooling water flows from the small basin by gravity to the cooling tower instead of returning to the Savannah River. After being cooled, it is pumped back to the 25-million-gal basin. River water is supplied only to make up for evaporation and the blowdown stream

Thermal and stability considerations for a supercritical water-cooled fast reactor during power-raising phase of plant startup

International Nuclear Information System (INIS)

Cai, Jiejin; Ishiwatari, Yuki; Oka, Yoshiaki; Ikejiri, Satoshi

2009-01-01

This paper describes thermal analyses and linear stability analyses of the Supercritical Water-cooled Fast Reactor with 'two-path' flow scheme during the power-raising phase of plant startup. For thermal consideration, the same criterion of the maximum cladding surface temperature (MCST) as applied to the normal operating condition is used. For thermal-hydraulic stability consideration, the decay ratio of 0.5 is applied, which is taken from BWRs. Firstly, we calculated the flow rate distribution among the parallel flow paths from the reactor vessel inlet nozzles to the mixing plenum below the core using a system analysis code. The parallel flow paths consist of the seed fuel assemblies cooled by downward flow, the blanket fuel assemblies cooled by downward flow and the downcomer. Then, the MCSTs are estimated for various reactor powers and feedwater flow rates with system analyses. The decay ratios are estimated with linear stability analyses. The available range of the reactor power and feedwater flow rate to satisfy the thermal and stability criteria is obtained. (author)

Solving the heat transfer in the cold rain of a cross flow cooling tower. N3S code - cooling tower release

International Nuclear Information System (INIS)

Grange, J.L.

1996-09-01

A simplified model for heat and mass transfer in the lower rainfall of a counter-flow cooling toward had to be implemented in the N3S code-cooling tower release It is built from an old code: ZOPLU. The air velocity field is calculated by N3S. The air and water temperature fields are solved by a Runge-Kutta method on a mesh in an adequate number of vertical plans. Heat exchange and drags correlations are given. And all the necessary parameters are specified. All the subroutines are described. They are taken from ZOPLU and modified in order to adapt their abilities to the N3S requirements. (author). 6 refs., 3 figs., 3 tabs., 3 appends

Brackish groundwater as an alternative source of cooling water for nuclear power plants in Israel

International Nuclear Information System (INIS)

Arad, A.; Olshina, A.

1984-01-01

The western Negev is being considered as a potential site for the location of a nuclear powerplant. Since this part of Israel has no surface water, the only alternatives for cooling water are piped-in water, Mediterranean water and local, brackish groundwater. The Judea Group aquifer was examined for its potential to provide the required amount of cooling water over the lifetime of the plant, without causing a drastic lowering of the regional water table. The salinity of the water tends to increase from east to west. Flow within the aquifer is in the direction of Beer Sheva, where the extraction rate is 32 to 35 million cu m/yr. This has resulted in a salinity creep of 5-10 mg Cl per year in the Beer Sheva area, which poses a danger of deterioration of its water supply in the long term. Given the assumed range of aquifer properties, extraction of brackish water for cooling purposes will not result in large changes in the regional water table. Exploitation of the more saline water to the southwest of Beer Sheva could preserve the quality of Beer Sheva's water supply, at the expense of an increase in the depth from which it must be pumped. 2 references, 7 figures, 2 tables

Numerical Simulation on Subcooled Boiling Heat Transfer Characteristics of Water-Cooled W/Cu Divertors

Science.gov (United States)

Han, Le; Chang, Haiping; Zhang, Jingyang; Xu, Tiejun

2015-04-01

In order to realize safe and stable operation of a water-cooled W/Cu divertor under high heating condition, the exact knowledge of its subcooled boiling heat transfer characteristics under different design parameters is crucial. In this paper, subcooled boiling heat transfer in a water-cooled W/Cu divertor was numerically investigated based on computational fluid dynamic (CFD). The boiling heat transfer was simulated based on the Euler homogeneous phase model, and local differences of liquid physical properties were considered under one-sided high heating conditions. The calculated wall temperature was in good agreement with experimental results, with the maximum error of 5% only. On this basis, the void fraction distribution, flow field and heat transfer coefficient (HTC) distribution were obtained. The effects of heat flux, inlet velocity and inlet temperature on temperature distribution and pressure drop of a water-cooled W/Cu divertor were also investigated. These results provide a valuable reference for the thermal-hydraulic design of a water-cooled W/Cu divertor. supported by the National Magnetic Confinement Fusion Science Program of China (No. 2010GB104005), Funding of Jiangsu Innovation Program for Graduate Education (CXLX12_0170), the Fundamental Research Funds for the Central Universities of China

Stability monitoring of a natural-circulation-cooled boiling water reactor

International Nuclear Information System (INIS)

Hagen, T.H.J.J. van der.

1989-01-01

Methods for monitoring the stability of a boiling water reactor (BWR) are discussed. Surveillance of BWR stability is of importance as problems were encountered in several large reactors. Moreover, surveying stability allows plant owners to operate at high power with acceptable stability margins. The results of experiments performed on the Dodewaard BWR (the Netherlands) are reported. This type reactor is cooled by natural circulation, a cooling principle that is also being considered for new reactor designs. The stability of this reactor was studied both with deterministic methods and by noise analysis. Three types of stability are distinguished and were investigated separately: reactor-kinetic stability, thermal-hydraulic stability and total-plant stability. It is shown that the Dodewaard reactor has very large stability margins. A simple yet reliable stability criterion is introduced. It can be derived on-line from thhe noise signal of ex-vessel neutron detectors during normal operation. The sensitivity of neutron detectors to in-core flux perturbations - reflected in the field-of-view of the detector - was calculated in order to insure proper stability surveillance. A novel technique is presented which enables the determination of variations of the in-core coolant velocity by noise correlation. The velocity measured was interpreted on the basis of experiments performed on the air/water flow in a model of a BWR coolant channel. It appeared from this analysis that the velocity measured was much higher than the volume-averaged water and air velocities and the volumetric flux. The applicability of the above-mentioned technique to monitoring of local channel-flow stability was tested. It was observed that stability effects on the coolant velocity are masked by other effects originating from the local flow pattern. Experimental and theoretical studies show a shorter effective fuel time constant in a BWR than was assumed. (author). 118 refs.; 73 figs.; 21 tabs

ON THE ORIGIN OF THE EXTENDED Hα FILAMENTS IN COOLING FLOW CLUSTERS

International Nuclear Information System (INIS)

McDonald, Michael; Veilleux, Sylvain; Mushotzky, Richard; Rupke, David S. N.

2010-01-01

We present a high spatial resolution Hα survey of 23 cooling flow clusters using the Maryland Magellan Tunable Filter, covering 1-2 orders of magnitude in cooling rate, dM/dt, temperature, and entropy. We find that 8/23 (35%) of our clusters have complex, filamentary morphologies at Hα, while an additional 7/23 (30%) have marginally extended or nuclear Hα emission, in general agreement with previous studies of line emission in cooling flow cluster brightest cluster galaxies. A weak correlation between the integrated near-UV luminosity and the Hα luminosity is also found for our complete sample with a large amount of scatter about the expected relation for photoionization by young stars. We detect Hα emission out to the X-ray cooling radius, but no further, in several clusters and find a strong correlation between the Hα luminosity contained in filaments and the X-ray cooling flow rate of the cluster, suggesting that the warm ionized gas is linked to the cooling flow. Furthermore, we detect a strong enhancement in the cooling properties of the intracluster medium (ICM) coincident with the Hα emission, compared to the surrounding ICM at the same radius. While the filaments in a few clusters may be entrained by buoyant radio bubbles, in general, the radially infalling cooling flow model provides a better explanation for the observed trends. The correlation of the Hα and X-ray properties suggests that conduction may be important in keeping the filaments ionized. The thinness of the filaments suggests that magnetic fields are an important part of channeling the gas and shielding it from the surrounding hot ICM.

Effect of solar radiation on the performance of cross flow wet cooling tower in hot climate of Iran

Science.gov (United States)

Banooni, Salem; Chitsazan, Ali

2016-11-01

In some cities such as Ahvaz-Iran, the solar radiation is very high and the annual-mean-daily of the global solar radiation is about 17.33 MJ m2 d-1. Solar radiation as an external heat source seems to affect the thermal performance of the cooling towers. Usually, in modeling cooling tower, the effects of solar radiation are ignored. To investigate the effect of sunshade on the performance and modeling of the cooling tower, the experiments were conducted in two different states, cooling towers with and without sunshade. In this study, the Merkel's approach and finite difference technique are used to predict the thermal behavior of cross flow wet cooling tower without sunshade and the results are compared with the data obtained from the cooling towers with and without sunshade. Results showed that the sunshade is very efficient and it reduced the outlet water temperature, the approach and the water exergy of the cooling tower up to 1.2 °C, 15 and 1.1 %, respectively and increased the range and the efficiency of the cooling tower up to 29 and 37 %, respectively. Also, the sunshade decreased the error between the experimental data of the cooling tower with sunshade and the modeling results of the cooling tower without sunshade 1.85 % in average.

Passive cooling in modern nuclear reactors

International Nuclear Information System (INIS)

Rouai, N. M.

1998-01-01

This paper presents some recent experimental results performed with the aim of understanding the mechanism of passive cooling. The AP 600 passive containment cooling system is simulated by an electrically heated vertical pipe, which is cooled by a naturally induced air flow and by a water film descending under gravity. The results demonstrate that although the presence of the water film improved the heat transfer significantly, the mode of heat transfer was very dependent on the experimental parameters. Preheating the water improved both film stability and overall cooling performance

Cooling of gas turbines IX : cooling effects from use of ceramic coatings on water-cooled turbine blades

Science.gov (United States)

Brown, W Byron; Livingood, John N B

1948-01-01

The hottest part of a turbine blade is likely to be the trailing portion. When the blades are cooled and when water is used as the coolant, the cooling passages are placed as close as possible to the trailing edge in order to cool this portion. In some cases, however, the trailing portion of the blade is so narrow, for aerodynamic reasons, that water passages cannot be located very near the trailing edge. Because ceramic coatings offer the possibility of protection for the trailing part of such narrow blades, a theoretical study has been made of the cooling effect of a ceramic coating on: (1) the blade-metal temperature when the gas temperature is unchanged, and (2) the gas temperature when the metal temperature is unchanged. Comparison is also made between the changes in the blade or gas temperatures produced by ceramic coatings and the changes produced by moving the cooling passages nearer the trailing edge. This comparison was made to provide a standard for evaluating the gains obtainable with ceramic coatings as compared to those obtainable by constructing the turbine blade in such a manner that water passages could be located very near the trailing edge.

Chlorinated cooling waters in the marine environment: development of effluent guidelines

Energy Technology Data Exchange (ETDEWEB)

Capuzzo, J M; Goldman, J C; Davidson, J A; Lawrence, S A

1977-07-01

The effects of free chlorine and chloramine on stage I lobster larvae and juvenile killifish were investigated in continuous flow bioassay units. In comparing mortality and changes in standard respiration rates during and after exposure to either chlorine form, significant respiratory stress was observed with exposure to sublethal levels. Sublethal responses to free and combined chlorine should be considered when establishing regulations for chlorine residuals in cooling waters.

On synthesis and optimization of cooling water systems with multiple cooling towers

CSIR Research Space (South Africa)

Gololo, KV

2011-01-01

Full Text Available -1 On Synthesis and Optimization of Cooling Water Systems with Multiple Cooling Towers Khunedi Vincent Gololo?? and Thokozani Majozi*? ? Department of Chemical Engineering, University of Pretoria, Lynnwood Road, Pretoria, 0002, South Africa ? Modelling...

Cooling water for SSC experiments: Supplemental Conceptual Design Report (SCDR)

International Nuclear Information System (INIS)

Doyle, R.E.

1989-01-01

This paper discusses the following topics on cooling water design on the superconducting super collider; low conductivity water; industrial cooling water; chilled water systems; and radioactive water systems

Cooling water conditioning and quality control for tokamaks

International Nuclear Information System (INIS)

Gootgeld, A.M.

1995-10-01

Designers and operators of Tokamaks and all associated water cooled, peripheral equipment, are faced with the task of providing and maintaining closed-loop, low conductivity, low impurity, cooling water systems. Most of these systems must provide large volumes of high quality cooling water at reasonable cost and comply with local and state government orders and EPA mandated national pretreatment standards and regulations. This paper discusses the DIII-D water quality requirements, the means used to obtain the necessary quality and the instrumentation used for control and monitoring. Costs to mechanically and chemically condition and maintain water quality are discussed as well as the various aspects of complying with government standards and regulations

Pressure control of a proton beam-irradiated water target through an internal flow channel-induced thermosyphon.

Science.gov (United States)

Hong, Bong Hwan; Jung, In Su

2017-07-01

A water target was designed to enhance cooling efficiency using a thermosyphon, which is a system that uses natural convection to induce heat exchange. Two water targets were fabricated: a square target without any flow channel and a target with a flow channel design to induce a thermosyphon mechanism. These two targets had the same internal volume of 8 ml. First, visualization experiments were performed to observe the internal flow by natural convection. Subsequently, an experiment was conducted to compare the cooling performance of both water targets by measuring the temperature and pressure. A 30-MeV proton beam with a beam current of 20 μA was used to irradiate both targets. Consequently, the target with an internal flow channel had a lower mean temperature and a 50% pressure drop compared to the target without a flow channel during proton beam irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Closed cooling water chemistry guidelines revision

International Nuclear Information System (INIS)

McElrath, Joel; Breckenridge, Richard

2014-01-01

This second revision of the Closed Cooling Water Chemistry Guideline addresses the use of chemicals and monitoring methods to mitigate corrosion, fouling, and microbiological growth in the closed cooling-water (CCW) systems of nuclear and fossil-fueled power plants. This revision has been endorsed by the utility chemistry community and represents another step in developing a more proactive chemistry program to limit or control closed cooling system degradation with increased consideration of corporate resources and plant-specific design and operating concerns. These guidelines were developed using laboratory data, operating experience, and input from organizations and utilities within and outside of the United States of America. It is the intent of the Revision Committee that these guidelines are applicable to all nuclear and fossil-fueled generating stations around the world. A committee of industry experts—including utility specialists, Institute of Nuclear Power Operations representatives, water-treatment service-company representatives, consultants, a primary contractor, and EPRI staff—collaborated in reviewing available data on closed cooling-water system corrosion and microbiological issues. Recognizing that each plant owner has a unique set of design, operating, and corporate concerns, the Guidelines Committee developed a methodology for plant-specific optimization. The guideline provides the technical basis for a reasonable but conservative set of chemical treatment and monitoring programs. The use of operating ranges for the various treatment chemicals discussed in this guideline will allow a power plant to limit corrosion, fouling, and microbiological growth in CCW systems to acceptable levels. The guideline now includes closed cooling chemistry regimes proven successful in use in the international community. The guideline provides chemistry constraints for the use of phosphates control, as well as pure water with pH control. (author)

Two-phase flow experiments in emergency core cooling feed through the hot leg for developing numerical models

International Nuclear Information System (INIS)

Staebler, T.; Meyer, L.; Schulenberg, T.; Laurien, E.

2006-01-01

When a leakage, a 'loss-of-coolant accident', occurs in a light water reactor, the emergency cooling system is able to supply large amounts of coolant to ensure residual heat removal. This supply can be routed through a special emergency cooling pipe, the 'scoop', into the horizontal section of the main coolant pipe, the 'hot leg'. At the same time, hot steam from the superheated, partly voided core flows against the coolant. This gives rise to a two-phase flow in the opposite direction. A factor of primary interest in this situation is whether the coolant supplied by the emergency cooling system will reach the reactor core. The research project is being conducted in order to compute the rate of water supply by numerical methods. The WENKA test facility has been designed and built at the Karlsruhe Research Center to verify numerical calculations. It can be used to study the fluid dynamics phenomena expected to arise in emergency coolant feeding into the hot leg; the necessary local data can be determined experimentally. An extensive database for validating the numerical calculations is then available to complete the experimental work. (orig.)

Constructal tree-shaped two-phase flow for cooling a surface

Energy Technology Data Exchange (ETDEWEB)

Zamfirescu, C.; Bejan, A. [Duke University, Durham, NC (United States). Dept. of Mechanical Engineering and Materials Science

2003-07-01

This paper documents the strong relation that exists between the changing architecture of a complex flow system and the maximization of global performance under constraints. The system is a surface with uniform heating per unit area, which is cooled by a network with evaporating two-phase flow. Illustrations are based on the design of the cooling network for a skating rink. The flow structure is optimized as a sequence of building blocks, which starts with the smallest (elemental volume of fixed size), and continues with assemblies of stepwise larger sizes (first construct, second construct, etc.). The optimized flow network is tree shaped. Three features of the elemental volume are optimized: the cross-sectional shape, the elemental tube diameter, and the shape of the elemental area viewed from above. The tree that emerges at larger scales is optimized for minimal amount of header material and fixed pressure drop. The optimal number of constituents in each new (larger) construct decreases as the size and complexity of the construct increase. Constructs of various levels of complexity compete: the paper shows how to select the optimal flow structure subject to fixed size (cooled surface), pressure drop and amount of header material. (author)

Membrane distillation of industrial cooling tower blowdown water

Directory of Open Access Journals (Sweden)

N.E. Koeman-Stein

2016-06-01

Full Text Available The potential of membrane distillation for desalination of cooling tower blowdown water (CTBD is investigated. Technical feasibility is tested on laboratory and pilot scale using real cooling tower blowdown water from Dow Benelux in Terneuzen (Netherlands. Two types of membranes, polytetrafluorethylene and polyethylene showed good performance regarding distillate quality and fouling behavior. Concentrating CTBD by a factor 4.5 while maintaining a flux of around 2 l/m2*h was possible with a water recovery of 78% available for reuse. Higher concentration factors lead to severe decrease in flux which was caused by scaling. Membrane distillation could use the thermal energy that would otherwise be discharged of in a cooling tower and function as a heat exchanger. This reduces the need for cooling capacity and could lead to a total reduction of 37% water intake for make-up water, as well as reduced energy and chemicals demands and greenhouse gas emissions.

Effect of wall thickness and helium cooling channels on duct magnetohydrodynamic flows

International Nuclear Information System (INIS)

He, Qingyun; Feng, Jingchao; Chen, Hongli

2016-01-01

Highlights: • MHD flows in ducts of different wall thickness compared with wall uniform. • Study of velocity, pressure distribution in ducts MHD flows with single pass of helium cooling channels. • Comparison of three types of dual helium cooling channels and acquisition of an option for minimum pressure drop. • A single short duct MHD flow in blanket without FCI has been simulated for pressure gradient analysis. - Abstract: The concept of dual coolant liquid metal (LM) blanket has been proposed in different countries to demonstrate the technical feasibility of DEMO reactor. In the system, helium gas and PbLi eutectic, separated by structure grid, are used to cool main structure materials and to be self-cooled, respectively. The non-uniform wall thickness of structure materials gives rise to wall non-homogeneous conductance ratio. It will lead to electric current distribution changes, resulting in significant changes in the velocity distribution and pressure drop of magnetohydrodynamic (MHD) flows. In order to investigate the effect of helium channels on MHD flows, different methods of numerical simulations cases are carried out including the cases of different wall thicknesses, single pass of helium cooling channels, and three types of dual helium cooling channels. The results showed that helium tubes are able to affect the velocity distribution in the boundary layer by forming wave sharp which transfers from Hartmann boundary layer to the core area. In addition, the potential profile and pressure drop in the cases have been compared to these in the case of walls without cooling channel, and the pressure gradient of a simplified single short duct MHD flow in blanket shows small waver along the central axis in the helium channel position.

Effect of wall thickness and helium cooling channels on duct magnetohydrodynamic flows

Energy Technology Data Exchange (ETDEWEB)

He, Qingyun; Feng, Jingchao; Chen, Hongli, E-mail: hlchen1@ustc.edu.cn

2016-02-15

Highlights: • MHD flows in ducts of different wall thickness compared with wall uniform. • Study of velocity, pressure distribution in ducts MHD flows with single pass of helium cooling channels. • Comparison of three types of dual helium cooling channels and acquisition of an option for minimum pressure drop. • A single short duct MHD flow in blanket without FCI has been simulated for pressure gradient analysis. - Abstract: The concept of dual coolant liquid metal (LM) blanket has been proposed in different countries to demonstrate the technical feasibility of DEMO reactor. In the system, helium gas and PbLi eutectic, separated by structure grid, are used to cool main structure materials and to be self-cooled, respectively. The non-uniform wall thickness of structure materials gives rise to wall non-homogeneous conductance ratio. It will lead to electric current distribution changes, resulting in significant changes in the velocity distribution and pressure drop of magnetohydrodynamic (MHD) flows. In order to investigate the effect of helium channels on MHD flows, different methods of numerical simulations cases are carried out including the cases of different wall thicknesses, single pass of helium cooling channels, and three types of dual helium cooling channels. The results showed that helium tubes are able to affect the velocity distribution in the boundary layer by forming wave sharp which transfers from Hartmann boundary layer to the core area. In addition, the potential profile and pressure drop in the cases have been compared to these in the case of walls without cooling channel, and the pressure gradient of a simplified single short duct MHD flow in blanket shows small waver along the central axis in the helium channel position.

A systemic approach for optimal cooling tower operation

International Nuclear Information System (INIS)

Cortinovis, Giorgia F.; Paiva, Jose L.; Song, Tah W.; Pinto, Jose M.

2009-01-01

The thermal performance of a cooling tower and its cooling water system is critical for industrial plants, and small deviations from the design conditions may cause severe instability in the operation and economics of the process. External disturbances such as variation in the thermal demand of the process or oscillations in atmospheric conditions may be suppressed in multiple ways. Nevertheless, such alternatives are hardly ever implemented in the industrial operation due to the poor coordination between the utility and process sectors. The complexity of the operation increases because of the strong interaction among the process variables. In the present work, an integrated model for the minimization of the operating costs of a cooling water system is developed. The system is composed of a cooling tower as well as a network of heat exchangers. After the model is verified, several cases are studied with the objective of determining the optimal operation. It is observed that the most important operational resources to mitigate disturbances in the thermal demand of the process are, in this order: the increase in recycle water flow rate, the increase in air flow rate and finally the forced removal of a portion of the water flow rate that enters the cooling tower with the corresponding make-up flow rate.

TRACG-CFD analysis of ESBWR reactor water cleanup shutdown cooling system mixing coefficient

International Nuclear Information System (INIS)

Gallardo, J.; Marquino, W.; Mistreanu, A.; Yang, J.

2015-09-01

The ESBWR is a 1520 nominal [M We] Generation III+ natural circulation boiling water reactor designed to high levels of safety utilizing features that have been successfully used before in operating BWRs, as well as standard features common to A BWR. In September of 2014, the US NRC has certified the ESBWR design for use in the USA. The RWCU/Sdc is an auxiliary system for the ESBWR nuclear island. Basic functions it performs include purifying the reactor coolant during normal operation and shutdown and providing shutdown cooling and cooldown to cold shutdown conditions. The performance of the RWCU system during shutdown cooling is directly related to the temperature of the water removed through the outlets, which is coupled with the vessel and F W temperatures through a thermal mixing coefficient. The complex three-dimensional (3-D) geometry of the BWR downcomer and lower plenum has a great impact on the flow mixing. Only a fine mesh technique like CFD can predict the 3-D temperature distribution in the RPV during shutdown and provide the RWCU/Sdc system inlet temperature. Plant shutdown is an unsteady event by nature and was modeled as a succession of CFD steady-state simulations. It is required to establish the mixing coefficient (which is a function of the heat balance and the core flow) during the operation of the RWCU system in the multiple shutdown cooling modes, and therefore a range of core flows needs to be estimated using quasi steady states obtained with TRACG. The lower end of that range is obtained from a system with minimal power decay heat and core flow; while the higher end corresponds to the power at the beginning of RWCU/Sdc operation when the cooldown is transferred to the RWCU/Sdc after the initial depressurization via the turbine bypass valves. Because the ESBWR RWCU/Sdc return and suction designs provide good mixing, the uniform mixing energy balance was found to be an adequate alternative for deriving the mixing coefficient. The CFD mass flow

TRACG-CFD analysis of ESBWR reactor water cleanup shutdown cooling system mixing coefficient

Energy Technology Data Exchange (ETDEWEB)

Gallardo, J. [UNAM, Facultad de Ingenieria, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marquino, W.; Mistreanu, A.; Yang, J., E-mail: euqrop@hotmail.com [General Electric Hitachi Nuclear Energy, Wilmington, 28401 North Carolina (United States)

2015-09-15

The ESBWR is a 1520 nominal [M We] Generation III+ natural circulation boiling water reactor designed to high levels of safety utilizing features that have been successfully used before in operating BWRs, as well as standard features common to A BWR. In September of 2014, the US NRC has certified the ESBWR design for use in the USA. The RWCU/Sdc is an auxiliary system for the ESBWR nuclear island. Basic functions it performs include purifying the reactor coolant during normal operation and shutdown and providing shutdown cooling and cooldown to cold shutdown conditions. The performance of the RWCU system during shutdown cooling is directly related to the temperature of the water removed through the outlets, which is coupled with the vessel and F W temperatures through a thermal mixing coefficient. The complex three-dimensional (3-D) geometry of the BWR downcomer and lower plenum has a great impact on the flow mixing. Only a fine mesh technique like CFD can predict the 3-D temperature distribution in the RPV during shutdown and provide the RWCU/Sdc system inlet temperature. Plant shutdown is an unsteady event by nature and was modeled as a succession of CFD steady-state simulations. It is required to establish the mixing coefficient (which is a function of the heat balance and the core flow) during the operation of the RWCU system in the multiple shutdown cooling modes, and therefore a range of core flows needs to be estimated using quasi steady states obtained with TRACG. The lower end of that range is obtained from a system with minimal power decay heat and core flow; while the higher end corresponds to the power at the beginning of RWCU/Sdc operation when the cooldown is transferred to the RWCU/Sdc after the initial depressurization via the turbine bypass valves. Because the ESBWR RWCU/Sdc return and suction designs provide good mixing, the uniform mixing energy balance was found to be an adequate alternative for deriving the mixing coefficient. The CFD mass flow

Simulation of an active cooling system for photovoltaic modules

International Nuclear Information System (INIS)

Abdelhakim, Lotfi

2016-01-01

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water also acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.

Simulation of an active cooling system for photovoltaic modules

Energy Technology Data Exchange (ETDEWEB)

Abdelhakim, Lotfi [Széchenyi István University of Applied Sciences, Department of Mathematics, P.O.Box 701, H-9007 Győr (Hungary)

2016-06-08

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water also acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.

Energy and exergy analysis of counter flow wet cooling towers

Directory of Open Access Journals (Sweden)

Saravanan Mani

2008-01-01

Full Text Available Cooling tower is an open system direct contact heat exchanger, where it cools water by both convection and evaporation. In this paper, a mathematical model based on heat and mass transfer principle is developed to find the outlet condition of water and air. The model is solved using iterative method. Energy and exergy analysis infers that inlet air wet bulb temperature is found to be the most important parameter than inlet water temperature and also variation in dead state properties does not affect the performance of wet cooling tower. .

Cooling nuclear reactor fuel

International Nuclear Information System (INIS)

Porter, W.H.L.

1975-01-01

Reference is made to water or water/steam cooled reactors of the fuel cluster type. In such reactors it is usual to mount the clusters in parallel spaced relationship so that coolant can pass freely between them, the coolant being passed axially from one end of the cluster in an upward direction through the cluster and being effective for cooling under normal circumstances. It has been suggested, however, that in addition to the main coolant flow an auxiliary coolant flow be provided so as to pass laterally into the cluster or be sprayed over the top of the cluster. This auxiliary supply may be continuously in use, or may be held in reserve for use in emergencies. Arrangements for providing this auxiliary cooling are described in detail. (U.K.)

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

Science.gov (United States)

Afshari, Ebrahim; Ziaei-Rad, Masoud; Jahantigh, Nabi

2016-06-01

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.

Experimental study of discharging PCM ceiling panels through nocturnal radiative cooling

DEFF Research Database (Denmark)

Bourdakis, Eleftherios; Péan, Thibault Q.; Gennari, Luca

PhotoVoltaic/Thermal (PV/T) panels were used for cooling water through the principle of nocturnal radiative cooling. This water was utilised for discharging Phase Change Material (PCM) which was embedded in ceiling panels in a climate chamber. Three different sets of flow rates were examined...... for the solar and the PCM loops, for five days each. The highest examined water flow rate (210 l/h) in the PCM loop provided the best thermal environment in the climate chamber, namely 92% of the occupancy time was within the range of Category III of Standard EN 15251. Although the lowest examined water flow...... rate (96 l/h) in the solar loop provided the highest average cooling power, due to the significant variations in the weather conditions during the three experimental cases, made it impossible to determine to which extent the difference in the cooling power is due to the different water flow rate...

Environmental effects of large discharges of cooling water. Experiences from Swedish nuclear power plants

International Nuclear Information System (INIS)

Ehlin, Ulf; Lindahl, Sture; Neuman, Erik; Sandstroem, Olof; Svensson, Jonny

2009-07-01

Monitoring the environmental effects of cooling water intake and discharge from Swedish nuclear power stations started at the beginning of the 1960s and continues to this day. In parallel with long-term monitoring, research has provided new knowledge and methods to optimise possible discharge locations and design, and given the ability to forecast their environmental effects. Investigations into the environmental effects of cooling-water are a prerequisite for the issuing of power station operating permits by the environmental authorities. Research projects have been carried out by scientists at universities, while the Swedish Environmental Protection Agency, the Swedish Board of Fisheries, and the Swedish Meteorological and Hydrological Institute, SMHI, are responsible for the greater part of the investigations as well as of the research work. The four nuclear power plants dealt with in this report are Oskarshamn, Ringhals, Barsebaeck and Forsmark. They were taken into operation in 1972, 1975, 1975 and 1980 resp. - a total of 12 reactors. After the closure of the Barsebaeck plants in 2005, ten reactors remain in service. The maximum cooling water discharge from the respective stations was 115, 165, 50 and 135 m 3 /s, which is comparable to the mean flow of an average Swedish river - c:a 150 m 3 /s. The report summarizes studies into the consequences of cooling water intake and discharge. Radiological investigations made at the plants are not covered by this review. The strategy for the investigations was elaborated already at the beginning of the 1960s. The investigations were divided into pre-studies, baseline investigations and monitoring of effects. Pre-studies were partly to gather information for the technical planning and design of cooling water intake and outlet constructions, and partly to survey the hydrographic and ecological situation in the area. Baseline investigations were to carefully map the hydrography and ecology in the area and their natural

Water supply method to the fuel cell cooling water system; Nenryo denchi reikyakusuikei eno kyusui hoho

Energy Technology Data Exchange (ETDEWEB)

Urata, T. [Tokyo (Japan); Nishida, S. [Tokyo (Japan)

1996-12-17

The conventional fuel cell has long cooling water piping ranging from the fuel cell exit to the steam separator; in addition, the supply water is cooler than the cooling water. When the amount of supply water increases, the temperature of the cooling water is lowered, and the pressure fluctuation in the steam separator becomes larger. This invention relates to the water supply method of opening the supply water valve and supplying water from the supply water system to the cooling water system in accordance with the signal of the level sensor of the steam separator, wherein opening and closing of the supply valve are repeated during water supply. According to the method the pressure drop in every water supply becomes negligibly small; therefore, the pressure fluctuation of the cooling water system can be made small. The interval of the supply water valve from opening to closing is preferably from 3 seconds to 2 minutes. The method is effective when equipment for recovering heat from the cooling water is installed in the downstream pipeline of the fuel cell. 2 figs.

Pressure drop, steam content and turbulent cross exchange in water/steam flows

International Nuclear Information System (INIS)

Teichel, H.

1978-01-01

For describing the behaviour of two-phase flows of water and steam with the help of calculating patterns, a number of empirical correlations are required. - In this article, correlations for the friction pressure drop in water/steam flows are compared, as well as for the steam mass and the volumetric steam content with each other and with the test results on simple geometries. As the mutual effect between cooling chanels plays an important part at the longitudinal flow through bar bundles, the appertaining equations are evaluated, in addition. (orig.) 891 HP [de

A model for radionuclide transport in the Cooling Water System

International Nuclear Information System (INIS)

Kahook, S.D.

1992-08-01

A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA

Optimization of cooling tower performance analysis using Taguchi method

Directory of Open Access Journals (Sweden)

Ramkumar Ramakrishnan

2013-01-01

Full Text Available This study discuss the application of Taguchi method in assessing maximum cooling tower effectiveness for the counter flow cooling tower using expanded wire mesh packing. The experiments were planned based on Taguchi’s L27 orthogonal array .The trail was performed under different inlet conditions of flow rate of water, air and water temperature. Signal-to-noise ratio (S/N analysis, analysis of variance (ANOVA and regression were carried out in order to determine the effects of process parameters on cooling tower effectiveness and to identity optimal factor settings. Finally confirmation tests verified this reliability of Taguchi method for optimization of counter flow cooling tower performance with sufficient accuracy.

Cooling methods of station blackout scenario for LWR plants

International Nuclear Information System (INIS)

2012-01-01

The objective of this study is to analyze the cooling method of station blackout scenario for both the BWR and PWR plants by RELAP5 code and to check the validity of the cooling method proposed by the utilities. In the BWR plant cooling scenario, the Reactor Core Isolation Cooling System (RCIC), which is operated with high pressure steam from the reactor, injects cooling water into the reactor to keep the core water level. The steam generated in the core is released into the suppression pool at containment vessel to condense. To restrict the containment vessel pressure rising, the ventilation from the wet-well is operated. The scenario is analyzed by RELAP5 and CONTEMPT-LT code. In the PWR plant scenario, the primary pressure is decreased by the turbine-driven auxiliary feed water system operated with secondary side steam of the steam generators (SGs). And the core cooling is kept by the natural circulation flow at the primary loop. The analytical method of un-uniform flow behavior among the SG U-tubes, which affects the natural circulation flow rate, is developed. (author)

Influence of detergents on water drift in cooling towers

Science.gov (United States)

Vitkovicova, Rut

An influence of detergents on the water drift from the cooling tower was experimentally investigated. For this experimental measurements was used a model cooling tower, especially an experimental aerodynamic line, which is specially designed for the measurement and monitoring of processes taking place around the eliminators of the liquid phase. The effect of different concentrations of detergent in the cooling water on the drift of water droplets from a commonly used type eliminator was observed with visualization methods.

Safety system consideration of a supercritical-water cooled fast reactor with simplified PSA

International Nuclear Information System (INIS)

Lee, J.H.; Oka, Y.; Koshizuka, S.

1999-01-01

The probabilistic safety of the supercritical-water cooled fast reactor (SCFR) is evaluated with the simplified probabilistic safety assessment (PSA) methodology. SCFR has a once-through direct cycle where all feedwater flows through the core to the turbine at supercritical pressure. There are no recirculation loops in the once-through direct cycle system, which is the most important difference from the current light water reactor (LWR). The main objective of the present study is to assess the effect of this difference on the safety in the stage of conceptual design study. A safety system configuration similar to the advanced boiling water reactor (ABWR) is employed. At loss of flow events, no natural recirculation occurs. Thus, emergency core flow should be quickly supplied before the completion of the feedwater pump coastdown at a loss of flow accident. The motor-driven high pressure coolant injection (MD-HPCI) system cannot be used for the quick core cooling due to the delay of the emergency diesel generator (D/G) start-up. Accordingly, an MD-HPCI system in an ABWR is substituted by a turbine-driven (TD-) HPCI system for the SCFR. The calculated core damage frequency (CDF) is a little higher than that of the Japanese ABWR and a little lower than that of the Japanese BWR when Japanese data are employed for initiating event frequencies. Four alternatives to the safety system configurations are also examined as a sensitivity analysis. This shows that the balance of the safety systems designed here is adequate. Consequently, though the SCFR has a once-through coolant system, the CDF is not high due to the diversity of feedwater systems as the direct cycle characteristics

Discussion on numerical simulation techniques for patterns of water vapor rise and droplet deposition at NPP cooling tower

International Nuclear Information System (INIS)

Guo Dongpeng; Yao Rentai

2010-01-01

Based on the working principle of cooling tower, analysis and comparison are made of both advantages and disadvantages of the numerical simulation models, such as ORFAD, KUMULUS, ISCST:A, ANL/UI, CFD etc., which predict the rise and droplet deposition pattern of cooling tower water vapor. The results showed that, CFD model is currently a better model that is used of three-dimensional Renault fluid flow equations predicting the rise and droplet deposition pattern of cooling tower water vapor. The impact of the line trajectory deviation and the speed change inn plume rising is not considered in any other models, and they can not be used for prediction of particle rise and droplet deposition when a larger particle or large buildings in the direction of cooling tower. (authors)

Wetland Water Cooling Partnership: The Use of Constructed Wetlands to Enhance Thermoelectric Power Plant Cooling and Mitigate the Demand of Surface Water Use

Energy Technology Data Exchange (ETDEWEB)

Apfelbaum, Steven L. [Applied Ecological Services Inc., Brodhead, WI (United States); Duvall, Kenneth W. [Sterling Energy Services, LLC, Atlanta, GA (United States); Nelson, Theresa M. [Applied Ecological Services Inc., Brodhead, WI (United States); Mensing, Douglas M. [Applied Ecological Services Inc., Brodhead, WI (United States); Bengtson, Harlan H. [Sterling Energy Services, LLC, Atlanta, GA (United States); Eppich, John [Waterflow Consultants, Champaign, IL (United States); Penhallegon, Clayton [Sterling Energy Services, LLC, Atlanta, GA (United States); Thompson, Ry L. [Applied Ecological Services Inc., Brodhead, WI (United States)

2013-12-01

Through the Phase I study segment of contract #DE-NT0006644 with the U.S. Department of Energy’s National Energy Technology Laboratory, Applied Ecological Services, Inc. and Sterling Energy Services, LLC (the AES/SES Team) explored the use of constructed wetlands to help address stresses on surface water and groundwater resources from thermoelectric power plant cooling and makeup water requirements. The project objectives were crafted to explore and develop implementable water conservation and cooling strategies using constructed wetlands (not existing, naturally occurring wetlands), with the goal of determining if this strategy has the potential to reduce surface water and groundwater withdrawals of thermoelectric power plants throughout the country. Our team’s exploratory work has documented what appears to be a significant and practical potential for augmenting power plant cooling water resources for makeup supply at many, but not all, thermoelectric power plant sites. The intent is to help alleviate stress on existing surface water and groundwater resources through harvesting, storing, polishing and beneficially re-using critical water resources. Through literature review, development of conceptual created wetland plans, and STELLA-based modeling, the AES/SES team has developed heat and water balances for conventional thermoelectric power plants to evaluate wetland size requirements, water use, and comparative cooling technology costs. The ecological literature on organism tolerances to heated waters was used to understand the range of ecological outcomes achievable in created wetlands. This study suggests that wetlands and water harvesting can provide a practical and cost-effective strategy to augment cooling waters for thermoelectric power plants in many geographic settings of the United States, particularly east of the 100th meridian, and in coastal and riverine locations. The study concluded that constructed wetlands can have significant positive

Water cooled reactor technology: Safety research abstracts no. 1

International Nuclear Information System (INIS)

1990-01-01

The Commission of the European Communities, the International Atomic Energy Agency and the Nuclear Energy Agency of the OECD publish these Nuclear Safety Research Abstracts within the framework of their efforts to enhance the safety of nuclear power plants and to promote the exchange of research information. The abstracts are of nuclear safety related research projects for: pressurized light water cooled and moderated reactors (PWRs); boiling light water cooled and moderated reactors (BWRs); light water cooled and graphite moderated reactors (LWGRs); pressurized heavy water cooled and moderated reactors (PHWRs); gas cooled graphite moderated reactors (GCRs). Abstracts of nuclear safety research projects for fast breeder reactors are published independently by the Nuclear Energy Agency of the OECD and are not included in this joint publication. The intention of the collaborating international organizations is to publish such a document biannually. Work has been undertaken to develop a common computerized system with on-line access to the stored information

Influence of cold-water immersion on limb blood flow after resistance exercise.

Science.gov (United States)

Mawhinney, Chris; Jones, Helen; Low, David A; Green, Daniel J; Howatson, Glyn; Gregson, Warren

2017-06-01

This study determined the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow following resistance exercise. Twelve males completed 4 sets of 10-repetition maximum squat exercise and were then immersed, semi-reclined, into 8°C or 22°C water for 10-min, or rested in a seated position (control) in a randomized order on different days. Rectal and thigh skin temperature, muscle temperature, thigh and calf skin blood flow and superficial femoral artery blood flow were measured before and after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). The colder water reduced thigh skin temperature and deep muscle temperature to the greatest extent (P lower (55%) than the control post-immersion (P water similarly reduce femoral artery and cutaneous blood flow responses but not muscle temperature following resistance exercise.

Effects of Building‒roof Cooling on Flow and Distribution of Reactive Pollutants in street canyons

Science.gov (United States)

Park, S. J.; Choi, W.; Kim, J.; Jeong, J. H.

2016-12-01

The effects of building‒roof cooling on flow and dispersion of reactive pollutants were investigated in the framework of flow dynamics and chemistry using a coupled CFD‒chemistry model. For this, flow characteristics were analyzed first in street canyons in the presence of building‒roof cooling. A portal vortex was generated in street canyon, producing dominant reverse and outward flows near the ground in all the cases. The building‒roof cooling increased horizontal wind speeds at the building roof and strengthened the downward motion near the downwind building in the street canyon, resultantly intensifying street canyon vortex strength. The flow affected the distribution of primary and secondary pollutants. Concentrations of primary pollutants such as NOx, VOC and CO was high near the upwind building because the reverse flows were dominant at street level, making this area the downwind region of emission sources. Concentration of secondary pollutant such as O3 was lower than the background near the ground, where NOX concentrations were high. Building‒roof cooling decreased the concentration of primary pollutants in contrasted to those under non‒cooling conditions. In contrast, building‒roof cooling increased O3 by reducing NO concentrations in urban street canyon compared to concentrations under non‒cooling conditions.

Influence of cold water immersion on limb and cutaneous blood flow at rest.

Science.gov (United States)

Gregson, Warren; Black, Mark A; Jones, Helen; Milson, Jordon; Morton, James; Dawson, Brian; Atkinson, Greg; Green, Daniel J

2011-06-01

Cold water immersion reduces exercise-induced muscle damage. Benefits may partly arise from a decline in limb blood flow; however, no study has comprehensively investigated the influence of different degrees of cooling undertaken via cold water immersion on limb blood flow responses. To determine the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow. Controlled laboratory study. Nine men were placed in a semireclined position and lowered into 8°C or 22°C water to the iliac crest for two 5-minute periods interspersed with 2 minutes of nonimmersion. Rectal and thigh skin temperature, deep and superficial muscle temperature, heart rate, mean arterial pressure, thigh cutaneous blood velocity (laser Doppler), and superficial femoral artery blood flow (duplex ultrasound) were measured during immersion and for 30 minutes after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). Reductions in rectal temperature (8°C, 0.2° ± 0.1°C; 22°C, 0.1° ± 0.1°C) and thigh skin temperature (8°C, 6.2° ± 0.5°C; 22°C, 3.2° ± 0.2°C) were greater in 8°C water than in 22°C (P water compared with 22°C (P = .01). These data suggest that immersion at both temperatures resulted in similar whole limb blood flow but, paradoxically, more blood was distributed to the skin in the colder water. This suggests that colder temperatures may be associated with reduced muscle blood flow, which could provide an explanation for the benefits of cold water immersion in alleviating exercise-induced muscle damage in sports and athletic contexts. Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation because of greater reductions in muscle blood flow.

Influence of detergents on water drift in cooling towers

Directory of Open Access Journals (Sweden)

Vitkovicova Rut

2017-01-01

Full Text Available An influence of detergents on the water drift from the cooling tower was experimentally investigated. For this experimental measurements was used a model cooling tower, especially an experimental aerodynamic line, which is specially designed for the measurement and monitoring of processes taking place around the eliminators of the liquid phase. The effect of different concentrations of detergent in the cooling water on the drift of water droplets from a commonly used type eliminator was observed with visualization methods.

Concept of CFD model of natural draft wet-cooling tower flow

Directory of Open Access Journals (Sweden)

Hyhlík T.

2014-03-01

Full Text Available The article deals with the development of CFD model of natural draft wet-cooling tower flow. The physical phenomena taking place within a natural draft wet cooling tower are described by the system of conservation law equations along with additional equations. The heat and mass transfer in the counterflow wet-cooling tower fill are described by model [1] which is based on the system of ordinary differential equations. Utilization of model [1] of the fill allows us to apply commonly measured fill characteristics as shown by [2].The boundary value problem resulting from the fill model is solved separately. The system of conservation law equations is interlinked with the system of ordinary differential equations describing the phenomena occurring in the counterflow wet-cooling tower fill via heat and mass sources and via boundary conditions. The concept of numerical solution is presented for the quasi one dimensional model of natural draft wet-cooling tower flow. The simulation results are shown.

Effect of closed loop cooling water transit time on containment cooling

International Nuclear Information System (INIS)

Smith, R.P.; Vossahlik, J.E.; Goodwin, E.F.

1996-01-01

Long term containment cooling analyses in nuclear plant systems are usually conducted assuming a quasi steady-state process, that is, a steady state evaluation of the cooling system is completed for each calculational step. In reality, fluid transport in the system, and heat addition to system components may affect the heat removal rate of the system. Transient effects occurring during system startup may affect the maximum temperatures experienced in the system. It is important to ensure that such transient effects do not affect operation of the system (e.g., cause a high temperature trip). To evaluate the effect of fluid transit delays, a closed loop cooling water system model has been developed that incorporates the fluid transport times when determining the closed loop cooling system performance. This paper describes the closed loop cooling system model as implemented in the CONTEMPT-LT/028 code. The evaluation of the transient temperature response of the closed loop cooling system using the model is described. The paper also describes the effect of fluid transit time on the overall containment cooling performance

COOLING WATER ISSUES AND OPPORTUNITIES AT U.S. NUCLEAR POWER PLANTS

Energy Technology Data Exchange (ETDEWEB)

Gary Vine

2010-12-01

This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes “Best Technology Available” for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant’s steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R&D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.

COOLING WATER ISSUES AND OPPORTUNITIES AT U.S. NUCLEAR POWER PLANTS

International Nuclear Information System (INIS)

Vine, Gary

2010-01-01

This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes 'Best Technology Available' for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant's steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R and D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.

Calandria cooling structure in pressure tube reactor

International Nuclear Information System (INIS)

Hyugaji, Takenori; Sasada, Yasuhiro.

1976-01-01

Purpose: To contrive the structure of a heavy water distributing device in a pressure tube reactor thereby to reduce the variation in the cooling function thereof due to the welding deformation and installation error. Constitution: A heating water distributing plate is provided at the lower part of the upper tubular plate of a calandria tank to form a heavy water distributing chamber between both plates and a plurality of calandria tubes. Heavy water which has flowed in the upper part of the heavy water distributing plate from the heavy water inlet nozzle flows down through gaps formed around the calandria tubes, whereby the cooling of the calandria tank and the calandria tubes is carried out. In the above described calandria cooling structure, a heavy water distributing plate support is provided to secure the heavy water distributing plate and torus-shaped heavy water distributing rings are fixed to holes formed in the heavy water distributing plate penetrating through the calandria tubes thereby to form torus-shaped heavy water outlet ports each having a space. (Seki, T.)

Mechanism of falling water limitation in two-phase counter flow through single hole vertical channel

International Nuclear Information System (INIS)

Sudo, Yukio; Ohnuki, Akira

1983-01-01

In the safety evaluation at the time of loss coolant accident, which is a credible accident in LWRs, recently main effort has been concentrated to the optimum evaluation calculation, and the grasp of vapor-liquid two-phase flow phenomena has become important. As one of the important phenomena, there is the limitation of falling water in two-phase counter flow through a vertical channel. This phenomenon is divided into the limitation of falling water stored in an upper plenum to a core through an upper core-supporting plate and a tie plate at the time of reflooding, and the limitation of falling emergency core-cooling water in downcomer channels at the time of reflooding in PWRs, under the presence of rising steam flow. In both cases, the evaluation of the quantity of falling water is important, because it contributes directly to core cooling. In this research, in order to clarify the mechanism of limitation of falling water in two-phase vertical counter flow, first, two-phase flow of air-water system through a single-hole vertical channel was taken up, and the effect of main parameters was experimentally studied. At the same time, the theoretical investigation was performed, and the comparison with the experimental results obtained so far was carried out. The different mechanisms for short and long channels gave the good results. (Kako, I.)

Environmental compatible cooling water treatment chemicals; Umweltvertraegliche Chemikalien in der Kuehlwasserkonditionierung

Energy Technology Data Exchange (ETDEWEB)

Gartiser, S; Urich, E

2002-02-01

In Germany about 32 billion m{sup 3}/a cooling water are discharged from industrial plants and power industry. These are conditioned partly with biocides, scaling and corrosion inhibitors. Within the research project the significance of cooling water chemicals was evaluated, identifying the chemicals from product information, calculating their loads from consumption data of more than 180 cooling plants and investigating the basic data needed for an environmental hazard assessment. Additionally the effects of cooling water samples and products were determined in biological test systems. Batch tests were performed under defined conditions in order to measure the inactivation of cooling water biocides. (orig.)

Passive cooling system for liquid metal cooled nuclear reactors with backup coolant flow path

International Nuclear Information System (INIS)

Hunsbedt, A.; Boardman, C.E.

1993-01-01

A dual passive cooling system for liquid metal cooled nuclear fission reactors is described, comprising the combination of: a reactor vessel for containing a pool of liquid metal coolant with a core of heat generating fissionable fuel substantially submerged therein, a side wall of the reactor vessel forming an innermost first partition; a containment vessel substantially surrounding the reactor vessel in spaced apart relation having a side wall forming a second partition; a first baffle cylinder substantially encircling the containment vessel in spaced apart relation having an encircling wall forming a third partition; a guard vessel substantially surrounding the containment vessel and first baffle cylinder in spaced apart relation having a side wall forming a forth partition; a sliding seal at the top of the guard vessel edge to isolate the dual cooling system air streams; a second baffle cylinder substantially encircling the guard vessel in spaced part relationship having an encircling wan forming a fifth partition; a concrete silo substantially surrounding the guard vessel and the second baffle cylinder in spaced apart relation providing a sixth partition; a first fluid coolant circulating flow course open to the ambient atmosphere for circulating air coolant comprising at lent one down comer duct having an opening to the atmosphere in an upper area thereof and making fluid communication with the space between the guard vessel and the first baffle cylinder and at least one riser duct having an opening to the atmosphere in the upper area thereof and making fluid communication with the space between the first baffle cylinder and the containment vessel whereby cooling fluid air can flow from the atmosphere down through the down comer duct and space between the forth and third partitions and up through the space between the third and second partition and the riser duct then out into the atmosphere; and a second fluid coolant circulating flow

A Massive, Cooling-Flow-Induced Starburst in the Core of a Highly Luminous Galaxy Cluster

Science.gov (United States)

McDonald, M.; Bayliss, M.; Benson, B. A.; Foley, R. J.; Ruel, J.; Sullivan, P.; Veilleux, S.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.;

Hybrid cooling tower Neckarwestheim 2 cooling function, emission, plume dispersion

International Nuclear Information System (INIS)

Braeuning, G.; Ernst, G.; Maeule, R.; Necker, P.

1990-01-01

The fan-assisted hybrid cooling tower of the 1300 MW power plant Gemeinschafts-Kernkraftwerk Neckarwestheim 2 was designed and constructed based on results from theoretical and experimental studies and experiences from a smaller prototype. The wet part acts in counterflow. The dry part is arranged above the wet part. Each part contains 44 fans. Special attention was payed to the ducts which mix the dry into the wet plume. The cooling function and state, mass flow and contents of the emission were measured. The dispersion of the plume in the atmosphere was observed. The central results are presented in this paper. The cooling function corresponds to the predictions. The content of drifted cooling water in the plume is extremely low. The high velocity of the plume in the exit causes an undisturbed flow into the atmosphere. The hybrid operation reduces visible plumes strongly, especially in warmer and drier ambient air

Natural Flow Air Cooled Photovoltaics

Science.gov (United States)

Tanagnostopoulos, Y.; Themelis, P.

2010-01-01

Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

Asbestos in cooling-tower waters. Final report

International Nuclear Information System (INIS)

Lewis, B.A.G.

1979-03-01

Water discharges from cooling towers constructed with asbestos fill were found to contain chrysotile--asbestos fibers at concentrations as high as 10 8 fibers/liter. The major source of these fibers, appears to be the components of the towers rather than the air drawn through the towers or the makeup water taken into the towers. Suggested mechanisms for the release of chrysotile fibers from cooling-tower fill include freeze-thaw cycles and dissolution of the cement due to acidic components of the circulating water. Ash- or other material-settling ponds were found to reduce asbestos-fiber concentrations in cooling-tower effluent. The literature reviewed did not support the case for a causal relationship between adverse human health effects and drinking water containing on the order of 10 6 chrysotile--asbestos fibers/liter; for this and other reasons, it is not presently suggested that the use of asbestos fill be discontinued. However, caution and surveillance are dictated by the uncertainties in the epidemiological studies, the absence of evidence for a safe threshold concentration in water, and the conclusive evidence for adverse effects from occupational exposure. It is recommended that monitoring programs be carried out at sites where asbestos fill is used; data from such programs can be used to determine whether any mitigative measures should be taken. On the basis of estimates made in this study, monitoring for asbestos in drift from cooling towers does not appear to be warranted

Design of the Flow Plates for a Dual Cooled Fuel Assembly

International Nuclear Information System (INIS)

Kim, Jae Yong; Yoon, Kyung Ho; Lee, Young Ho; Lee, Kang Hee; Kim, Hyung Kyu

2009-01-01

In a dual cooled fuel assembly, the array and position of fuels are changed from those of a conventional PWR fuel assembly to achieve a power uprating. The flow plate provides flow holes to direct the heated coolant into/out of the fuel assembly and structural intensity to insure that the fuel rod is axially restrained within the spacer grids. So, flow plates of top/bottom end pieces (TEP/BEP) have to be modified into proper shape. Because the flow holes' area of a flow plate affects pressure drop, the flow holes' area must be larger than/equal to that of conventional flow plates. And design criterion of the TEP/BEP says that the flow plate should withstand a 22.241 kN axial load during handling lest a calculated stress intensity should exceed the Condition I allowable stress. In this paper, newly designed flow plates of a TEP/BEP are suggested and stress analysis is conducted to evaluate strength robustness of the flow plates for the dual cooled fuel assembly

Neutronic and thermal hydraulic assessment of fast reactor cooling by water of super critical parameters

International Nuclear Information System (INIS)

Baranaev, Yu. D.; Glebov, A. P.; Ukraintsev, V. F.; Kolesov, V. V.

2007-01-01

Necessity of essential improvement of competitiveness for reactors on light water determines development of new generation power reactors on water of super critical parameters. The main objective of these projects is reaching of high efficiency coefficients while decreasing of investment to NPP and simplification of thermal scheme and high safety level. International programme of IV generation in which super critical reactors present is already started. In the frame of this concept specific Super Critical Fast Reactor with tight lattice of pitch is developing by collaboration of the FEI and IATE. In present article neutronic and thermal hydraulic assessment of fast reactor with plutonium MOX fuel and a core with a double-path of super critical water cooling is presented (SCFR-2X). The scheme of double path of coolant via the core in which the core is divided by radius on central and periphery parts with approximately equal number of fuel assemblies is suggested. Periferia part is cooling while down coming coolant movement. At the down part of core into the mix chamber flows from the periphery assemblies joining and come to the inlet of the central part which is cooling by upcoming flow. Eight zone of different content of MOX fuel are used (4 in down coming and 4 in upcoming) sub zones. Calculation of fuel burn-up and approximate scheme of refueling is evaluated. Calculation results are presented and discussed

Water mist effect on cooling range and efficiency of casting die

Directory of Open Access Journals (Sweden)

R. Władysiak

2008-12-01

Full Text Available This project is showing investigation results of cooling process of casting die in the temperature range 570÷100 °C with 0.40 MPa compressed air and water mist streamed under pressure 0.25÷0.45 MPa in air jet 0.25÷0.50 MPa using open cooling system.The character and the speed of changes of temperature, forming of the temperture’s gradient along parallel layer to cooled surface of die is shawing with thermal and derivative curves. The effect of kind of cooling factor on the temperature and time and distance from cooling nozzle is presented in the paper. A designed device for generating the water mist cooling the die and the view of sprying water stream is shown here. It’s proved that using of the water mist together with the change of heat transfer interface increases intensity of cooling in the zone and makes less the range cooling zone and reduces the porosity of cast microstructure.

Thermal calculations for water cooled research reactors

International Nuclear Information System (INIS)

Fabrega, S.

1979-01-01

The formulae and the more important numerical data necessary for thermic calculations on the core of a research reactor, cooled with low pressure water, are presented. Most of the problems met by the designer and the operator are dealt with (calculations margins, cooling after shut-down). Particular cases are considered (gas release, rough walls, asymmetric cooling slabs etc.), which are not generally envisaged in works on general thermics

Supercritical-pressure, once-through cycle light water cooled reactor concept

International Nuclear Information System (INIS)

Oka, Yoshiaki; Koshizuka, Seiichi

2001-01-01

The purpose of the study is to develop new reactor concepts for the innovation of light water reactors (LWR) and fast reactors. Concept of the once-through coolant cycle, supercritical-pressure light water cooled reactor was developed. Major aspects of reactor design and safety were analysed by the computer codes which were developed by ourselves. It includes core design of thermal and fast reactors, plant system, safety criteria, accident and transient analysis, LOCA, PSA, plant control, start up and stability. High enthalpy rise as supercritical boiler was achieved by evaluating the cladding temperature directly during transients. Fundamental safety principle of the reactor is monitoring coolant flow rate instead of water level of LWR. The reactor system is compact and simple because of high specific enthalpy of supercritical water and the once-through cycle. The major components are similar to those of LWR and supercritical thermal plant. Their temperature are within the experiences in spite of the high outlet coolant temperature. The reactor is compatible with tight fuel lattice fast reactor because of the high head pumps and low coolant flow rate. The power rating of the fast reactor is higher than the that of thermal reactor because of the high power density. (author)

Water-cooled grid ''wires'' for direct converters

International Nuclear Information System (INIS)

Schwer, C.J.

1976-01-01

A study was conducted to determine the feasibility of internal convective cooling of grid ''wires'' for direct converters. Detailed computer calculations reveal that the use of small diameter water cooled tubes as grid ''wires'' is feasible for a considerable range of lengths and thermal fluxes

Safety design of Pb-Bi-cooled direct contact boiling water fast reactor (PBWFR)

International Nuclear Information System (INIS)

Takahashi, Minoru; Uchida, Shoji; Yamada, Yumi; Koyama, Kazuya

2008-01-01

In Pb-Bi-cooled direct contact boiling water small fast reactor (PBWFR), steam is generated by direct contact of feedwater with primary Pb-Bi coolant above the core, and Pb-Bi coolant is circulated by steam lift pump in chimneys. Safety design has been developed to show safety features of PBWFR. Negative void reactivity is inserted even if whole of the core and upper plenum are voided hypothetically by steam intrusion from above. The control rod ejection due to coolant pressure is prevented using in-vessel type control rod driving mechanism. At coolant leak from reactor vessel and feedwater pipes, Pb-Bi coolant level in the reactor vessel required for decay heat removal is kept using closed guard vessel. Dual pipes for feedwater are employed to avoid leak of water. Although there is no concern of loss of flow accident due to primary pump trip, feedwater pump trip initiates loss of coolant flow (LOF). Injection of high pressure water slows down the flow coast down of feedwater at the LOF event. The unprotected loss of flow and heat sink (ATWS) has been evaluated, which shows that the fuel temperatures are kept lower than the safety limits. (author)

Emergency reactor container cooling facility

International Nuclear Information System (INIS)

Suzuki, Hiroaki; Matsumoto, Tomoyuki.

1992-01-01

The present invention concerns an emergency cooling facility for a nuclear reactor container having a pressure suppression chamber, in which water in the suppression chamber is effectively used for cooling the reactor container. That is, the lower portion of a water pool in the pressure suppression chamber and the inside of the reactor container are connected by a pipeline. The lower end of the pipeline and a pressurized incombustible gas tank disposed to the outside of the reactor container are connected by a pipeline by way of valves. Then, when the temperature of the lower end of the pressure vessel exceeds a predetermined value, the valves are opened. If the valves are opened, the incombustible gas flows into the lower end of the pipeline connecting the lower portion of the water pool in the pressure suppression chamber and the inside of the reactor container. Since the inside of the pipeline is a two phase flow comprising a mixture of a gas phase and a liquid phase, the average density is decreased. Therefore, the water level of the two phase flow is risen by the level difference between the inside and the outside of the pipeline and, finally, the two phase mixture is released into the reactor container. As a result, the reactor container can be cooled by water in the suppression chamber by a static means without requiring pumps. (I.S.)

A novel method to design water spray cooling system to protect floating roof atmospheric storage tanks against fires

Directory of Open Access Journals (Sweden)

Iraj Alimohammadi

2015-01-01

Full Text Available Hydrocarbon bulk storage tank fires are not very common, but their protection is essential due to severe consequences of such fires. Water spray cooling system is one of the most effective ways to reduce damages to a tank from a fire. Many codes and standards set requirements and recommendations to maximize the efficiency of water spray cooling systems, but these are widely different and still various interpretations and methods are employed to design such systems. This article provides a brief introduction to some possible design methods of cooling systems for protection of storage tanks against external non-contacting fires and introduces a new method namely “Linear Density Method” and compares the results from this method to the “Average Method” which is currently in common practice. The average Method determines the flow rate for each spray nozzle by dividing the total water demand by the number of spray nozzles while the Linear Density Method determines the nozzle flow rate based on the actual flow over the surface to be protected. The configuration of the system includes a one million barrel crude oil floating roof tank to be protected and which is placed one half tank diameter from a similar adjacent tank with a full surface fire. Thermal radiation and hydraulics are modeled using DNV PHAST Version 6.53 and Sunrise PIPENET Version 1.5.0.2722 software respectively. Spray nozzles used in design are manufactured by Angus Fire and PNR Nozzles companies. Schedule 40 carbon steel pipe is used for piping. The results show that the cooling system using the Linear Density Method consumes 3.55% more water than the design using the average method assuming a uniform application rate of 4.1 liters per minute. Despite higher water consumption the design based on Linear Density Method alleviates the problems associated with the Average Method and provides better protection.

Reduced Volume Prototype Spacesuit Water Membrane Evaporator; A Next-Generation Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

Science.gov (United States)

Makinen, Janice V.; Anchondo, Ian; Bue, Grant C.; Campbell, Colin; Colunga, Aaron

2013-01-01

Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the reduced volume prototype (RVP) spacesuit water membrane evaporator (SWME). The RVP SWME is the third generation of hollow fiber SWME hardware. Like its predecessors, RVP SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Major design improvements, including a 36% reduction in volume, reduced weight, and a more flight-like backpressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. The development of these evaporative cooling systems will contribute to a more robust and comprehensive AEMU PLSS.

Mixed convection in a two-phase flow cooling loop

International Nuclear Information System (INIS)

Janssens-Maenhout, G.; Daubner, M.; Knebel, J.U.

2002-03-01

This report summarizes the numerical simulations using the CFD code CFX4.1 which has additional models for subcooled flow boiling phenomena and the interfacial forces. The improved CFX4.1 code can be applied to the design of boiling induced mixed convection cooling loops in a defined parameter range. The experimental part describes the geysering experiments and the instability effects on the two-phase natural circulation flow. An experimentally validated flow pattern map in the Phase Change Number - Subcooling Number (N PCh - N Sub ) diagram defines the operational range in which flow instabilities such as geysering can be expected. One important perspective of this combined experimental/numerical work, which is in the field of two-phase flow, is its application to the development of accelerator driven systems (ADS). The main objective on an ADS is its potential to transmute minor actinides and long-lived fission products, thus participating in closing the fuel cycle. The development of an ADS is an important issue within the Euratom Fifth FP on Partitioning and Transmutation. One concept of an ADS, which is investigated in more detail within the ''preliminary design study of an experimental ADS'' Project (PDS-XADS) of the Euratom Fifth FP, is the XADS lead-bismuth cooled Experimental ADS of ANSALDO. An essential feature of this concept is the natural circulation of the primary coolant within the reactor pool. The natural circulation, which is driven by the density differences between the blanket and the heat exchanger, is enhanced by the injection of the nitrogen cover gas through spargers located in a riser part just above the blanket. This so-called gas-lift pump system has not been investigated in more detail nor has this gas-lift pump system been numerically/experimentally confirmed. The knowledge gained within the SUCO Programe, i.e. the modelling of the interfacial forces, the experimental work on flow instabilities and the modelling of the interfacial area

Mixed convection in a two-phase flow cooling loop

Energy Technology Data Exchange (ETDEWEB)

Janssens-Maenhout, G.; Daubner, M.; Knebel, J.U.

2002-03-01

This report summarizes the numerical simulations using the CFD code CFX4.1 which has additional models for subcooled flow boiling phenomena and the interfacial forces. The improved CFX4.1 code can be applied to the design of boiling induced mixed convection cooling loops in a defined parameter range. The experimental part describes the geysering experiments and the instability effects on the two-phase natural circulation flow. An experimentally validated flow pattern map in the Phase Change Number - Subcooling Number (N{sub PCh} - N{sub Sub}) diagram defines the operational range in which flow instabilities such as geysering can be expected. One important perspective of this combined experimental/numerical work, which is in the field of two-phase flow, is its application to the development of accelerator driven systems (ADS). The main objective on an ADS is its potential to transmute minor actinides and long-lived fission products, thus participating in closing the fuel cycle. The development of an ADS is an important issue within the Euratom Fifth FP on Partitioning and Transmutation. One concept of an ADS, which is investigated in more detail within the ''preliminary design study of an experimental ADS'' Project (PDS-XADS) of the Euratom Fifth FP, is the XADS lead-bismuth cooled Experimental ADS of ANSALDO. An essential feature of this concept is the natural circulation of the primary coolant within the reactor pool. The natural circulation, which is driven by the density differences between the blanket and the heat exchanger, is enhanced by the injection of the nitrogen cover gas through spargers located in a riser part just above the blanket. This so-called gas-lift pump system has not been investigated in more detail nor has this gas-lift pump system been numerically/experimentally confirmed. The knowledge gained within the SUCO Programe, i.e. the modelling of the interfacial forces, the experimental work on flow instabilities and the

Analysis on small long life reactor using thorium fuel for water cooled and metal cooled reactor types

International Nuclear Information System (INIS)

Permana, Sidik

2009-01-01

Long-life reactor operation can be adopted for some special purposes which have been proposed by IAEA as the small and medium reactor (SMR) program. Thermal reactor and fast reactor types can be used for SMR and in addition to that program the utilization of thorium fuel as one of the candidate as a 'partner' fuel with uranium fuel which can be considered for optimizing the nuclear fuel utilization as well as recycling spent fuel. Fissile U-233 as the main fissile material for thorium fuel shows higher eta-value for wider energy range compared with other fissile materials of U-235 and Pu-239. However, it less than Pu-239 for fast energy region, but it still shows high eta-value. This eta-value gives the reactor has higher capability for obtaining breeding condition or high conversion capability. In the present study, the comparative analysis on small long life reactor fueled by thorium for different reactor types (water cooled and metal cooled reactor types). Light water and heavy water have been used as representative of water-cooled reactor types, and for liquid metal-cooled reactor types, sodium-cooled and lead-bismuth-cooled have been adopted. Core blanket arrangement as general design configuration, has been adopted which consist of inner blanket region fueled by thorium oxide, and two core regions (inner and out regions) fueled by fissile U-233 and thorium oxide with different percentages of fissile content. SRAC-CITATION and JENDL-33 have been used as core optimization analysis and nuclear data library for this analysis. Reactor operation time can reaches more than 10 years operation without refueling and shuffling for different reactor types and several power outputs. As can be expected, liquid metal cooled reactor types can be used more effective for obtaining long life reactor with higher burnup, higher power density, higher breeding capability and lower excess reactivity compared with water-cooled reactors. Water cooled obtains long life core operation

Quasi One-Dimensional Model of Natural Draft Wet-Cooling Tower Flow, Heat and Mass Transfer

Directory of Open Access Journals (Sweden)

Hyhlík Tomáš

2015-01-01

Full Text Available The article deals with the development of CFD (Computational Fluid Dynamics model of natural draft wet-cooling tower flow, heat and mass transfer. The moist air flow is described by the system of conservation laws along with additional equations. Moist air is assumed to be homogeneous mixture of dry air and water vapour. Liquid phase in the fill zone is described by the system of ordinary differential equations. Boundary value problem for the system of conservation laws is discretized in space using Kurganov-Tadmor central scheme and in time using strong stability preserving Runge-Kutta scheme. Initial value problems in the fill zone is solved by using standard fourth order Runge-Kutta scheme. The interaction between liquid water and moist air is done by source terms in governing equations.

New cooling regulation technology of secondary cooling station in DCS

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xuan; Yan, Jun-wei; Zhu, Dong-sheng; Liu, Fei-long; Lei, Jun-xi [The Key Lab of Enhanced Heat Transfer and Energy Conservation of Ministry of Education, School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China); Liang, Lie-quan [The Key Lab of E-Commerce Market Application Technology of Guangdong Province, Guangdong University of Business Studies, Guangzhou 510320 (China)

2008-07-01

In this paper, a kind of new control technology of secondary cooling station (constant flow rate/variable temperature difference) in district cooling system (DCS) is proposed in view of serial consequences including low efficiency and high operating cost caused by low temperature of supply water in DCS. This technology has been applied in DCS of Guangzhou University City. The result has already indicated that such technology can increase the supply and return temperatures of buildings, return water temperature of primary side in the plate heat exchanger unit, moreover, the efficiency of both the chiller and the whole system are improved significantly. (author)

Numerical study of saturation steam/water mixture flow and flashing initial sub-cooled water flow inside throttling devices

CERN Multimedia

CERN. Geneva

2016-01-01

In this work, a Computational Fluid-Dynamics (CFD) approach to model this phenomenon inside throttling devices is proposed. To validate CFD results, different nozzle geometries are analyzed, comparing numerical results with experimental data. Two cases are studied: Case 1: saturation steam/water mixture flow inside 2D convergent-divergent nozzle (inlet, outlet and throat diameter of nozzle are 0.1213m, 0.0452m and 0.0191m respectively). In this benchmark, a range of total inle...

Vortex Structure Effects on Impingement, Effusion, and Cross Flow Cooling of a Double Wall Configuration

Science.gov (United States)

Ligrani, P. M.

2018-03-01

A variety of different types of vortices and vortex structures have important influences on thermal protection, heat transfer augmentation, and cooling performance of impingement cooling, effusion cooling, and cross flow cooling. Of particular interest are horseshoe vortices, which form around the upstream portions of effusion coolant concentrations just after they exit individual holes, hairpin vortices, which develop nearby and adjacent to effusion coolant trajectories, and Kelvin-Helmholtz vortices which form within the shear layers that form around each impingement cooling jet. The influences of these different vortex structures are described as they affect and alter the thermal performance of effusion cooling, impingement cooling, and cross flow cooling, as applied to a double wall configuration.

Improving the efficiency of natural draft cooling towers

International Nuclear Information System (INIS)

Smrekar, J.; Oman, J.; Sirok, B.

2006-01-01

This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted

Improving the efficiency of natural draft cooling towers

Energy Technology Data Exchange (ETDEWEB)

Smrekar, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia); Oman, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)]. E-mail: janez.oman@fs.uni-lj.si; Sirok, B. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)

2006-06-15

This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted.

Boundary layer transition observations on a body of revolution with surface heating and cooling in water

Science.gov (United States)

Arakeri, V. H.

1980-04-01

Boundary layer flow visualization in water with surface heat transfer was carried out on a body of revolution which had the predicted possibility of laminar separation under isothermal conditions. Flow visualization was by in-line holographic technique. Boundary layer stabilization, including elimination of laminar separation, was observed to take place on surface heating. Conversely, boundary layer destabilization was observed on surface cooling. These findings are consistent with the theoretical predictions of Wazzan et al. (1970).

A photoionization model for the optical line emission from cooling flows

Science.gov (United States)

Donahue, Megan; Voit, G. M.

1991-01-01

The detailed predictions of a photoionization model previously outlined in Voit and Donahue (1990) to explain the optical line emission associated with cooling flows in X-ray emitting clusters of galaxies are presented. In this model, EUV/soft X-ray radiation from condensing gas photoionizes clouds that have already cooled. The energetics and specific consequences of such a model, as compared to other models put forth in the literature is discussed. Also discussed are the consequences of magnetic fields and cloud-cloud shielding. The results illustrate how varying the individual column densities of the ionized clouds can reproduce the range of line ratios observed and strongly suggest that the emission-line nebulae are self-irradiated condensing regions at the centers of cooling flows.

Design change of tower cooling water system for proton accelerator research center

International Nuclear Information System (INIS)

Jeon, G. P.; Kim, J. Y.; Song, I. T.; Min, Y. S.; Mun, K. J.; Cho, J. S.; Nam, J. M.; Park, S. S.; Han, Y. G.

2012-01-01

The Tower Cooling Water System (TC) is designed to reject the heat load generated by operating the accelerators and the utility facilities through the component cooling water (CCW) heat exchangers. The circulating water discharged from the circulating water pumps passes through the CCW heat exchangers, the Chiller condenser and the air compressor, and the heated circulating water is return to the cooling tower for the heat removal. In this study, The design of Tower Cooling Water System is changed as follows : At First, The quantity of cells is changed into six in order to operate the cooling tower accurately correspond with condition of each equipment of head loads. The fans of cooling tower are controlled by the signal of TEW installed in the latter parts of it. The type of circulation water pump is modified to centrifugal pump and debris filter system is deleted

Design change of tower cooling water system for proton accelerator research center

Energy Technology Data Exchange (ETDEWEB)

Jeon, G. P.; Kim, J. Y.; Song, I. T.; Min, Y. S.; Mun, K. J.; Cho, J. S.; Nam, J. M.; Park, S. S.; Han, Y. G. [KAERI, Daejeon (Korea, Republic of)

2012-10-15

The Tower Cooling Water System (TC) is designed to reject the heat load generated by operating the accelerators and the utility facilities through the component cooling water (CCW) heat exchangers. The circulating water discharged from the circulating water pumps passes through the CCW heat exchangers, the Chiller condenser and the air compressor, and the heated circulating water is return to the cooling tower for the heat removal. In this study, The design of Tower Cooling Water System is changed as follows : At First, The quantity of cells is changed into six in order to operate the cooling tower accurately correspond with condition of each equipment of head loads. The fans of cooling tower are controlled by the signal of TEW installed in the latter parts of it. The type of circulation water pump is modified to centrifugal pump and debris filter system is deleted.

A three-dimensional mathematical model to predict air-cooling flow and temperature distribution of wire loops in the Stelmor air-cooling system

International Nuclear Information System (INIS)

Hong, Lingxiang; Wang, Bo; Feng, Shuai; Yang, Zhiliang; Yu, Yaowei; Peng, Wangjun; Zhang, Jieyu

2017-01-01

Highlights: • A 3-dimentioanl mathematical models for complex wire loops was set up in Stelmor. • The air flow field in the cooling process was simulated. • The convective heat transfer coefficient was simulated coupled with air flow field. • The temperature distribution with distances was predicted. - Abstract: Controlling the forced air cooling conditions in the Stelmor conveyor line is important for improving the microstructure and mechanical properties of steel wire rods. A three-dimensional mathematical model incorporating the turbulent flow of the cooling air and heat transfer of the wire rods was developed to predict the cooling process in the Stelmor air-cooling line of wire rolling mills. The distribution of cooling air from the plenum chamber and the forced convective heat transfer coefficient for the wire loops were simulated at the different locations over the conveyor. The temperature profiles and cooling curves of the wire loops in Stelmor conveyor lines were also calculated by considering the convective heat transfer, radiative heat transfer as well as the latent heat during transformation. The calculated temperature results using this model agreed well with the available measured results in the industrial tests. Thus, it was demonstrated that this model can be useful for studying the air-cooling process and predicting the temperature profile and microstructure evolution of the wire rods.

Water-cooled non-thermal gliding arc for adhesion improvement of glass-fibre-reinforced polyester

DEFF Research Database (Denmark)

Kusano, Yukihiro; Sørensen, Bent F.; Løgstrup Andersen, Tom

2013-01-01

A non-equilibrium quenched plasma is prepared using a gliding-arc discharge generated between diverging electrodes and extended by a gas flow. It can be operated at atmospheric pressure and applied to plasma surface treatment to improve adhesion properties of material surfaces. In this work, glass......-fibre-reinforced polyester plates were treated using an atmospheric pressure gliding-arc discharge with air flow to improve adhesion with a vinylester adhesive. The electrodes were water-cooled so as to operate the gliding arc continually. The treatment improved wettability and increased the density of oxygen...

Multi-gate Pitot tube for the measurement of water flow in cooling systems; Tubo de Pitot multi-puertos para la medicion de flujo de agua en sistemas de enfriamiento

Energy Technology Data Exchange (ETDEWEB)

Figueroa Ibarra, Luis; Rodriguez Martinez, Jose Hugo; Santabarbara Botello, Marcelino [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2007-07-01

In this article the design of a novel measuring device of water flowing in large diameter pipes is described. A description is made of the instrument commonly used at present for this purpose (simple Pitot tube), whose design is based on the Standard CTI Code ATC-105 published by the Cooling Tower Institute (CTI ATC-105, 2000). The disadvantages of the simple Pitot tube in comparison with the new proposed device are emphasized (Multi-gate Pitot tube), of which its construction and design is described in detail. In the present article are also shown the results obtained of the circulation water flow measurements, performed in the cooling system of a fossil fuel power plant. These results are compared with the results of flow measurement obtained by means of the simulation of the thermodynamic cycle of the power station, using commercial software. [Spanish] En este articulo se describe el diseno de un novedoso medidor de flujo de agua que circula en tuberias de gran diametro. Se hace una descripcion del instrumento comunmente usado en la actualidad para dicho proposito (tubo de Pitot simple), cuyo diseno se basa en el estandar CTI Code ATC-105 publicado por el Cooling Tower Institute (CTI ATC-105, 2000). Se puntualizan las desventajas del tubo de Pitot simple en comparacion con el nuevo dispositivo propuesto (tubo de Pitot Multi-puertos), del cual se describe detalladamente su construccion y diseno. En el presente articulo tambien se muestran los resultados obtenidos de las mediciones de flujo de agua de circulacion, realizadas en el sistema de enfriamiento de una central termoelectrica. Dichos resultados son comparados con los resultados de flujo obtenidos mediante simulacion del ciclo termodinamico de la central, usando un software comercial.

Corrosion inhibition measures in primary cooling water system during refurbishment of Cirus, re-commissioning and subsequent operation

International Nuclear Information System (INIS)

Rai, K.K.; Ramesh, N.; Sharma, R.C.

2008-01-01

Cirus is a 40 MWth, heavy water moderated, demineralized light water cooled, natural uranium fuelled research reactor. Reactor was commissioned in year 1960 and operated satisfactorily till 1990. After that availability factor started decreasing mainly due to equipment outage exhibiting signs of ageing. Based upon systematic ageing studies and assessment of condition of systems, structures and components, a refurbishment plan including safety upgrades was drawn up. Reactor was shut down in October 1997 for execution of jobs. After completion of refurbishment jobs reactor was started back in October 2002 and power operation was achieved in 2003. Primary cooling water (PCW) system consists of re-circulating pumps, heat exchangers, expansion tank, piping, valves, emergency storage reservoir (Ball Tank) and other components. Normally the fission heat from fuel is removed by re-circulating coolant in closed loop and transferred to seawater via heat exchangers. In case of outage of pumps, shut down cooling is provided by flow of water from Ball Tank under gravity to the underground dump tanks. The dissolved oxygen is maintained below 2 ppm and pH is maintained neutral to minimize corrosion of fuel cladding (Aluminum). This paper highlights the experience gained during segmentation of primary cooling water pipelines for pressure testing, measures taken to corrosion inhibition of primary cooling water lines to permit execution of refurbishment jobs, inspections and actions taken to repair/replace the corroded PCW pipe line segments, observations regarding corrosion related failures, re-commissioning of the system after refurbishment, assessment for safe reactor operation and experience during power operation. (author)

Frost protection for atmospheric cooling tower

International Nuclear Information System (INIS)

Legrand, G.

1987-01-01

When the atmospheric temperature is near or lower than zero it is necessary to reduce the air flow entering in a cooling tower. A wire netting mounted on the air inlet is sprinkled with cold water. The level of the ice curtain and consequently the air flow is regulated by aspersion by hot water [fr

The potential for the recovery and reuse of cooling water in Taiwan

Energy Technology Data Exchange (ETDEWEB)

You, Shu-Hai; Tseng, Dyi-Hwa; Guo, Gia-Luen; Yang, Jyh-Jian [Graduate Institute of Environmental Engineering, National Central University, Chungli (Taiwan, Province of China)

1999-04-01

The cooling water is the major part of industrial water use in Taiwan, either from the view of demand priority or supply volume. In order to save water, the loading of supply system can be reduced if the cooling water can be recovered and reused. For this reason, exploration of the recent operation status of the cooling water system has become essential in Taiwan. This study was initially focused on the current applications and reuse trends of cooling water in oil refineries, chemical industry, steel mills, food industry, electronics works, textile plants and power stations. According to the statistical analysis, the portable water and groundwater are the primary sources of makeup water for cooling systems. The multiple-chemicals method and makeup treatment are increasingly accepted for the reclamation of cooling water. On the other hand, sidestream treatment and blowdown reuse are not popular in Taiwan. The recovery rate of blowdown is only 26.8%. The fact of higher cost is the major reason to depress the willingness of recovery. Some representative plants had been selected for case study. However, most cooling water systems are only operated by operator`s experience according to field investigation. In each case, the water quality indexes were used to evaluate the operational condition of cooling water systems. There was no case plant found to be operated at appropriate cycles of concentration. This paper also presented the bottlenecks of conservation technologies of cooling water in Taiwan. These bottlenecks include increasing the cycles of concentration, the reuse of wastewater, and the blowdown treatment for reuse. This paper also demonstrates that the recovery and reuse of cooling water has great potential and is feasible for the available technologies in present Taiwan, but the industries are still unwilling to upgrade because of initial cost. Finally, some approaches associated with technology, economics, environment and policy are proposed to be a

Experimental study of gas engine driven air to water heat pump in cooling mode

International Nuclear Information System (INIS)

Elgendy, E.; Schmidt, J.

2010-01-01

Nowadays a sustainable development for more efficient use of energy and protection of the environment is of increasing importance. Gas engine heat pumps represent one of the most practicable solutions which offer high energy efficiency and environmentally friendly for heating and cooling applications. In this paper, the performance characteristics of gas engine driven heat pump used in water cooling were investigated experimentally without engine heat recovery. The effects of several important factors (evaporator water inlet temperature, evaporator water volume flow rate, ambient air temperature, and engine speed) on the performance of gas engine driven heat pump were studied in a wide range of operating conditions. The results showed that primary energy ratio of the system increased by 22.5% as evaporator water inlet temperature increased from 13 o C to 24 o C. On the other hand, varying of engine speed from 1300 rpm to 1750 rpm led to decrease in system primary energy ratio by 13%. Maximum primary energy ratio has been estimated with a value of two over a wide range of operating conditions.

MHD/gas turbine systems designed for low cooling water requirements

International Nuclear Information System (INIS)

Annen, K.D.; Eustis, R.H.

1983-01-01

The MHD/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consist of a coal-fired MHD plant with an air turbine bottoming plant and require no cooling water. In addition to the base case systems, systems were considered which included the addition of a vapor cycle bottoming plant to improve the thermal efficiency. These systems require a small amount of cooling water. The results show that the MHD/gas turbine systems have very good thermal and economic performances. The base case I MHD/gas turbine system (782 MW /SUB e/ ) requires no cooling water, has a heat rate which is 13% higher, and a cost of electricity which is only 7% higher than a comparable MHD/steam system (878 MW /SUB e/ ) having a cooling tower heat load of 720 MW. The case I vapor cycle bottomed systems have thermal and economic performances which approach and even exceed those of the MHD/steam system, while having substantially lower cooling water requirements. Performances of a second-generation MHD/gas turbine system and an oxygen-enriched, early commercial system are also evaluated. An analysis of nitric oxide emissions shows compliance with emission standards

Cool-Water Carbonates, SEPM Special Publication No. 56

Science.gov (United States)

Hallock, Pamela

Doesn't field work on modern carbonates mean scuba diving on spectacular coral reefs in gin-clear water teeming with brightly colored fish? Not if you are one of the researchers that Jonathan Clarke of the Western Mining Corporation Ltd., in Preston, Victoria, Australia, assembled at a workshop in Geelong, Victoria, in January 1995. Their field work involves research cruises in high-latitude oceans, where mal de mer and chilling winds are constant companions. Many braved 10-m seas in modest-sized research vessels to sample shelves stripped of fine sediments by storm waves whose effects can reach to depths exceeding 200 m. Noel James of Queen's University in Kingston, Ontario, carefully lays the groundwork for the book in a paper titled, “The Cool-Water Carbonate Depositional Realm,” which will assuredly become a standard reading assignment in advanced undergraduate-and graduate-level courses in carbonate sedimentology. James skillfully shows how cool-water carbonates are part of the greater carbonate depositional spectrum. By expanding recognition of the possible range of carbonate environments, sedimentologists expand their ability to understand and interpret ancient carbonates, particularly Paleozoic limestones that often show striking similarities to modern cool-water sediments. James' paper is followed by nine papers on modern cool-water carbonates, seven on Tertiary environments, and seven examples from Mesozoic and Paleozoic limestones

Skin cooling on contact with cold materials: the effect of blood flow during short-term exposures.

Science.gov (United States)

Jay, Ollie; Havenith, George

2004-03-01

This study investigates the effect of blood flow upon the short-term (cooling response in order to ascertain whether sufferers of circulatory disorders, such as the vasospastic disorder Raynaud's disease, are at a greater risk of cold injury than people with a normal rate of blood flow. Eight female volunteers participated, touching blocks of stainless steel and nylon with a finger contact force of 2.9 N at a surface temperature of -5 degrees C under occluded and vasodilated conditions. Contact temperature (Tc) of the finger pad was measured over time using a T-type thermocouple. Forearm blood flow was measured using strain gauge plethysmography. Contact cooling responses were analysed by fitting a modified Newtonian cooling curve. A significant difference was found between the starting skin temperatures for the two blood flow conditions (Peffect of blood flow was found upon any of the derived cooling curve parameters characterizing the skin cooling response (P>0.05). It is hypothesized that the finger contact force used (2.9 N) and the resultant pressure upon the tissue of the contact finger pad restricted the blood supply to the contact area under both blood flow conditions; therefore, no effect of blood flow was found upon the parameters describing the contact cooling response. Whilst the findings of this study are sufficient to draw a conclusion for those in a working environment, i.e. contact forces below 2.9 N will seldom be encountered, a further study will be required to ascertain conclusively whether blood flow does affect the contact cooling response at a finger contact force low enough to allow unrestricted blood flow to the finger pad. Further protocol improvements are also recommended.

Laboratory study on the cooling effect of flash water evaporative cooling technology for ventilation and air-conditioning of buildings

DEFF Research Database (Denmark)

Fang, Lei; Yuan, Shu; Yang, Jianrong

environments and the other simulated an air-conditioned indoor environment. The flash water evaporation cooling device was installed in the chamber that simulated indoor environment. The air from the chamber simulating outdoor environment was introduced into the cooling device and cooled by the flash water......, is effective for ventilation and air-conditioning in warm/hot and dry climate zones. The technology can provide fresh outdoor air with a temperature of 4 to 7 °C lower than room air temperature.......This paper presents a simple cooling technology using flash water evaporation. The technology combines a water atomizer with a plate heat exchanger used for heat recovery of a ventilation system. It is mainly used to cool the ventilation airflow from outdoors and is particularly suitable to be used...

State waste discharge permit application 400 Area secondary cooling water. Revision 2

International Nuclear Information System (INIS)

1996-01-01

This document constitutes the Washington Administrative Code 173-216 State Waste Discharge Permit Application that serves as interim compliance as required by Consent Order DE 91NM-177, for the 400 Area Secondary Cooling Water stream. As part of the Hanford Federal Facility Agreement and Consent Order negotiations, the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site that affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173-216 of the Washington Administrative Code, the State Waste Discharge Permitting Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order DE 91NM-177. The Consent Order DE 91NM-177 requires a series of permitting activities for liquid effluent discharges. Based upon compositional and flow rate characteristics, liquid effluent streams on the Hanford Site have been categorized into Phase 1, Phase 2, and Miscellaneous streams. This document only addresses the 400 Area Secondary Cooling Water stream, which has been identified as a Phase 2 stream. The 400 Area Secondary Cooling Water stream includes contribution streams from the Fuels and Materials Examination Facility, the Maintenance and Storage Facility, the 481-A pump house, and the Fast Flux Test Facility

The constructional design of cooling water discharge structures on German rivers

International Nuclear Information System (INIS)

Geldner, P.; Zimmermann, C.

1975-11-01

The present compilation of structures for discharging cooling water from power stations into rivers is an attempt to make evident developments in the constructional design of such structures and to give reasons for special structure shapes. A complete collection of all structures built in Germany, however, is difficult to realize because of the large number of power stations. For conventionally heated power stations therefore only a selection was made, while nuclear power stations in operation or under construction could almost completely be taken into account. For want of sufficient quantities of water for river water cooling, projected power stations are now almost exclusively designed for closed-circuit cooling so that the required discharge structures for elutrition water from the cooling towers as well as for the emergency and secondary cooling circuits have to be designed only for small amounts of water. (orig./HP) [de

Once-through cycle, supercritical-pressure light water cooled reactor concept

Energy Technology Data Exchange (ETDEWEB)

Oka, Y.; Koshizuka, S. [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab

2001-07-01

Concept of once-through cycle, supercritical-pressure light water cooled reactors was developed. The research covered major aspects of conceptual design such as cores of thermal and fast reactors, plant system and heat balance, safety system and criteria, accident and transient analysis, LOCA, PSA, plant control and start-up. The advantages of the reactor lie in the compactness of the plant from high specific enthalpy of supercritical water, the simplicity of the once-through cycle and the experiences of major component technologies which are based on supercritical fossil-fired power plants and LWRs. The operating temperatures of the major components are within the experience in spite of high coolant outlet temperature. The once-through cycle is compatible with the tight fuel lattice fast reactor because of high head pumps and small coolant flow rate. (author)

Once-through cycle, supercritical-pressure light water cooled reactor concept

International Nuclear Information System (INIS)

Oka, Y.; Koshizuka, S.

2001-01-01

Concept of once-through cycle, supercritical-pressure light water cooled reactors was developed. The research covered major aspects of conceptual design such as cores of thermal and fast reactors, plant system and heat balance, safety system and criteria, accident and transient analysis, LOCA, PSA, plant control and start-up. The advantages of the reactor lie in the compactness of the plant from high specific enthalpy of supercritical water, the simplicity of the once-through cycle and the experiences of major component technologies which are based on supercritical fossil-fired power plants and LWRs. The operating temperatures of the major components are within the experience in spite of high coolant outlet temperature. The once-through cycle is compatible with the tight fuel lattice fast reactor because of high head pumps and small coolant flow rate. (author)

An efficient continuous flow helium cooling unit for Moessbauer experiments

International Nuclear Information System (INIS)

Herbert, I.R.; Campbell, S.J.

1976-01-01

A Moessbauer continuous flow cooling unit for use with liquid helium over the temperature range 4.2 to 300K is described. The cooling unit can be used for either absorber or source studies in the horizontal plane and it is positioned directly on top of a helium storage vessel. The helium transfer line forms an integral part of the cooling unit and feeds directly into the storage vessel so that helium losses are kept to the minimum. The helium consumption is 0.12 l h -1 at 4.2 K decreasing to 0.055 l h -1 at 40 K. The unit is top loading and the exchange gas cooled samples can be changed easily and quickly. (author)

Two-dimensional modeling of water spray cooling in superheated steam

Directory of Open Access Journals (Sweden)

Ebrahimian Vahid

2008-01-01

Full Text Available Spray cooling of the superheated steam occurs with the interaction of many complex physical processes, such as initial droplet formation, collision, coalescence, secondary break up, evaporation, turbulence generation, and modulation, as well as turbulent mixing, heat, mass and momentum transfer in a highly non-uniform two-phase environment. While it is extremely difficult to systematically study particular effects in this complex interaction in a well defined physical experiment, the interaction is well suited for numerical studies based on advanced detailed models of all the processes involved. This paper presents results of such a numerical experiment. Cooling of the superheated steam can be applied in order to decrease the temperature of superheated steam in power plants. By spraying the cooling water into the superheated steam, the temperature of the superheated steam can be controlled. In this work, water spray cooling was modeled to investigate the influences of the droplet size, injected velocity, the pressure and velocity of the superheated steam on the evaporation of the cooling water. The results show that by increasing the diameter of the droplets, the pressure and velocity of the superheated steam, the amount of evaporation of cooling water increases. .

Method and apparatus for emergency cooling of a nuclear power plant

International Nuclear Information System (INIS)

Naito, Masanori; Chino, Koichi; Sato, Chikara; Inoue, Hisamichi.

1978-01-01

Purpose: To improve the cooling effect of spray water by eliminating the flow control effect for spray water due to increase in the steam pressure and flowing the entire spray water into the reactor core. Constitution: Upon emergency cooling of a reactor core by spraying coolants from above at the loss of coolant accident in a nuclear power plant, coolant is sprayed in a state where the temperature upon flowing into the reactor core is below the saturated temperature after heat exchange with vapors rising from the core. This enables to apply spray water always at a temperature and a flow rate in the range of whole volume falling irrespective of the water temperature in a pressure suppression pool. (Furukawa, Y.)

Study on Enhancement of Sub-Cooled Flow Boiling Heat Transfer and Critical Heat Flux of Solid-Water Two-Phase Mixture

International Nuclear Information System (INIS)

Yasuo Koizumi; Hiroyasu Ohtake; Tomoyuki Suzuki

2002-01-01

The influence of particle introduction into a subcooled water flow on boiling heat transfer and critical heat flux (CHF) was examined. When the water velocity was low, the particles crowded on the bottom wall of the flow channel and flowed just like sliding on the wall. When the water velocity was high, the particles were well dispersed in the water flow. In the non-boiling region, the heat transfer was augmented by the introduction of the particles into the water flow. As the introduction of the particles were increased, the augmentation was also increased in the high water flow rate region. However, it was independent upon the particle introduction rate in the low water flow rate region. The onset of boiling was delayed by the particle inclusion. The boiling heat transfer was enhanced by the particles. However, it was rather decreased in the high heat flux fully-developed-boiling region. The CHF was decreased by the particle inclusion in the low water flow region and was not affected in the high water flow region. (authors)

Helium-cooled nuclear reactor

International Nuclear Information System (INIS)

Longton, P.B.; Cowen, H.C.

1975-01-01

In helium cooled HTR's there is a by-pass circuit for cleaning purposes in addition to the main cooling circuit. This is to remove such impurities as hydrogen, methane, carbon monoxide and water from the coolant. In this system, part of the coolant successively flows first through an oxidation bed of copper oxide and an absorption bed of silica gel, then through activated charcoal or a molecular sieve. The hydrogen and carbon monoxide impurities are absorbed and the dry gas is returned to the main cooling circuit. To lower the hydrogen/water ratio without increasing the hydrogen fraction in the main cooling circuit, some of the hydrogen fraction converted into water is added to the cooling circuit. This is done, inter alia, by bypassing the water produced in the oxidation bed before it enters the absorption bed. The rest of the by-pass circuit, however, also includes an absorption bed with a molecular sieve. This absorbs the oxidized carbon monoxide fraction. In this way, such side effects as the formation of additional methane, carburization of the materials of the by-pass circuit or loss of graphite are avoided. (DG/RF) [de

Emergency core cooling system

International Nuclear Information System (INIS)

Kato, Ken.

1989-01-01

In PWR type reactors, a cooling water spray portion of emergency core cooling pipelines incorporated into pipelines on high temperature side is protruded to the inside of an upper plenum. Upon rupture of primary pipelines, pressure in a pressure vessel is abruptly reduced to generate a great amount of steams in the reactor core, which are discharged at a high flow rate into the primary pipelines on high temperature side. However, since the inside of the upper plenum has a larger area and the steam flow is slow, as compared with that of the pipelines on the high temperature side, ECCS water can surely be supplied into the reactor core to promote the re-flooding of the reactor core and effectively cool the reactor. Since the nuclear reactor can effectively be cooled to enable the promotion of pressure reduction and effective supply of coolants during the period of pressure reduction upon LOCA, the capacity of the pressure accumulation vessel can be decreased. Further, the re-flooding time for the reactor is shortened to provide an effect contributing to the improvement of the safety and the reduction of the cost. (N.H.)

Auxiliary equipment for cooling water in a reactor

International Nuclear Information System (INIS)

Konno, Yasuhiro; Sakairi, Toshiaki.

1975-01-01

Object: To effectively make use of pressure energy of reactor water, which has heretofore been discarded, to enable supply of emergency power supply of high reliability and to prevent spreading of environmental contamination. Structure: Sea water pumped by a sea water supply pump is fed to a heat exchanger. Reactor water carried through piping on the side to be cooled is removed in heat by the heat exchanger to be cooled and returned, and then again returned to the reactor. On the other hand, sea water heated by the heat exchanger is fed to a water wheel to drive the water wheel, after which it is discharged into a discharging path. A generator may be directly connected to the water wheel to use the electricity generated by the generator as the emergency power source. (Kamimura, M.)

Elements of Design Consideration of Once-Through Cycle, Supercritical-Pressure Light Water Cooled Reactor

International Nuclear Information System (INIS)

Yoshiaki Oka; Sei-ichi Koshizuka; Yuki Ishiwatari; Akifumi Yamaji

2002-01-01

The paper describes elements of design consideration of supercritical-pressure, light water cooled reactors as well as the status and prospects of the research and development. It summarizes the results of the conceptual design study at the University of Tokyo from 1989. The research and development started in Japan, Europe and USA. The major advantages of the reactors are 1. Compact reactor and turbines due to high specific enthalpy of supercritical water 2.Simple plant system because of the once-through coolant cycle 3.Use of the experience of LWR and fossil-fired power plants. The temperatures of the major components such as reactor pressure vessel, coolant pipes, pumps and turbines are within the experience, in spite of the high outlet coolant temperature. 4.Similarity to LWR safety design and criteria, but no burnout phenomenon 5.Potential cost reduction due to smaller material expenditure and short construction period 6.The smallest reactor not in power rating, but in plant sizes. 7.High-thermal efficiency and low coolant flow rate because of high enthalpy rise. 8.Water cooled reactors potentially free from SCC (stress corrosion cracking) problems. 9.Compatibility of tight-fuel-lattice fast reactor core due to small coolant flow rate, potentially easy shift to fast breeder reactor without changing coolant technology. 10.Potential of producing energy products such as hydrogen and high quality hydro carbons. (authors)

Emergency core cooling system

International Nuclear Information System (INIS)

Sato, Akira; Kobayashi, Masahide.

1983-01-01

Purpose: To enable a stable operation of an emergency core cooling system by preventing the system from the automatic stopping at an abnormally high level of the reactor water during its operation. Constitution: A pump flow rate signal and a reactor water level signal are used and, when the reactor water level is increased to a predetermined level, the pump flow rate is controlled by the reactor water level signal instead of the flow rate signal. Specifically, when the reactor water level is gradually increased by the water injection from the pump and exceeds a setting signal for the water level, the water level deviation signal acts as a demand signal for the decrease in the flow rate of the pump and the output signal from the water level controller is also decreased depending on the control constant. At a certain point, the output signal from the water level controller becomes smaller than the output signal from the flow rate controller. Thus, the output signal from the water level controller is outputted as the output signal for the lower level preference device. In this way, the reactor water level and the pump flow rate can be controlled within a range not exceeding the predetermined pump flow rate. (Horiuchi, T.)

Optimization of cooling tower performance analysis using Taguchi method

OpenAIRE

Ramkumar Ramakrishnan; Ragupathy Arumugam

2013-01-01

This study discuss the application of Taguchi method in assessing maximum cooling tower effectiveness for the counter flow cooling tower using expanded wire mesh packing. The experiments were planned based on Taguchi’s L27 orthogonal array .The trail was performed under different inlet conditions of flow rate of water, air and water temperature. Signal-to-noise ratio (S/N) analysis, analysis of variance (ANOVA) and regression were carried out in order to determine the effects of process...

Numerical Calculation of the Peaking Factor of a Water-Cooled W/Cu Monoblock for a Divertor

International Nuclear Information System (INIS)

Han Le; Chang Haiping; Zhang Jingyang; Xu Tiejun

2015-01-01

In order to accurately predict the incident critical heat flux (ICHF, the heat flux at the heated surface when CHF occurs) of a water-cooled W/Cu monoblock for a divertor, the exact knowledge of its peaking factors (f p ) under one-sided heating conditions with different design parameters is a key issue. In this paper, the heat conduction in the solid domain of a water-cooled W/Cu monoblock is calculated numerically by assuming the local heat transfer coefficients (HTC) of the cooling wall to be functions of the local wall temperature, so as to obtain f p . The reliability of the calculation method is validated by an experimental example result, with the maximum error of 2.1% only. The effects of geometric and flow parameters on the f p of a water-cooled W/Cu monoblock are investigated. Within the scope of this study, it is shown that the f p increases with increasing dimensionless W/Cu monoblock width and armour thickness (the shortest distance between the heated surface and Cu layer), and the maximum increases are 43.8% and 22.4% respectively. The dimensionless W/Cu monoblock height and Cu thickness have little effect on f p . The increase of Reynolds number and Jakob number causes the increase of f p , and the maximum increases are 6.8% and 9.6% respectively. Based on the calculated results, an empirical correlation on peaking factor is obtained via regression. These results provide a valuable reference for the thermal-hydraulic design of water-cooled divertors. (paper)

Estimation of the amount of surface contamination of a water cooled nuclear reactor by cooling water analysis

Energy Technology Data Exchange (ETDEWEB)

Nagy, G. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)]. E-mail: nagyg@sunserv.kfki.hu; Somogyi, A. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary); Patek, G. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Pinter, T. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Schiller, R. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)

2007-06-15

Calculations, based upon on-the-spot measurements, were performed to estimate the contamination of NPP primary circuit and spent fuel storage pool solid surfaces via the composition of the cooling water in connection with a non-nuclear incident in the Paks NPP. Thirty partially burnt-up fuel element bundles were damaged during a cleaning process, an incident which resulted in the presence of fission products in the cooling water of the cleaning tank (CT) situated in a separate pool (P1). Since this medium was in contact for an extended period of time with undamaged fuel elements to be used later and also with other structural materials of the spent fuel storage pool (SP), it was imperative to assess the surface contamination of these latter ones with a particular view to the amount of fission material. In want of direct methods, one was restricted to indirect information which rested mainly on the chemical and radiochemical data of the cooling water. It was found that (i) the most important contaminants were uranium, plutonium, cesium and cerium; (ii) after the isolation of P1 and SP and an extended period of filtering the only important contaminants were uranium and plutonium; (iii) the surface contamination of the primary circuit (PC) was much lower than that of either SP or P1; (iv) some 99% of the contamination was removed from the water by the end of the filtering process.

Flow-induced and acoustically induced vibration experience in operating gas-cooled reactors

International Nuclear Information System (INIS)

Halvers, L.J.

1977-03-01

An overview has been presented of flow-induced and acoustically induced vibration failures that occurred in the past in gas-cooled graphite-moderated reactors, and the importance of this experience for the Gas-Cooled Fast-Breeder Reactor (GCFR) project has been assessed. Until now only failures in CO 2 -cooled reactors have been found. No problems with helium-cooled reactors have been encountered so far. It is shown that most of the failures occurred because flow-induced and acoustically induced dynamic loads were underestimated, while at the same time not enough was known about the influence of environmental parameters on material behavior. All problems encountered were solved. The comparison of the influence of the gas properties on acoustically induced and flow-induced vibration phenomena shows that the interaction between reactor design and the thermodynamic properties of the primary coolant precludes a general preference for either carbon dioxide or helium. The acoustic characteristics of CO 2 and He systems are different, but the difference in dynamic loadings due to the use of one rather than the other remains difficult to predict. A slight preference for helium seems, however, to be justified

Operations improvement of the recycling water-cooling systems of sugar mills

Directory of Open Access Journals (Sweden)

Shcherbakov Vladimir Ivanovich

Full Text Available Water management in sugar factories doesn’t have analogues in its complexity among food industry enterprises. Water intensity of sugar production is very high. Circulation water, condensed water, pulp press water and others are used in technological processes. Water plays the main role in physical, chemical, thermotechnical processes of beet processing and sugar production. As a consequence of accession of Russia to the WTO the technical requirements for production processes are changing. The enforcements of ecological services to balance scheme of water consumption and water disposal increased. The reduction of fresh water expenditure is one of the main tasks in economy of sugar industry. The substantial role in fresh water expenditure is played by efficiency of cooling and aeration processes of conditionally clean waters of the 1st category. The article contains an observation of the technologies of the available solutions and recommendations for improving and upgrading the existing recycling water-cooling systems of sugar mills. The authors present the block diagram of the water sector of a sugar mill and a method of calculating the optimal constructive and technological parameters of cooling devices. Water cooling towers enhanced design and upgrades are offered.

An operational experience with cooling tower water system in chilling plant

International Nuclear Information System (INIS)

Rajan, Manju B.; Roy, Ankan; Ravi, K.V.

2015-01-01

Cooling towers are popular in industries as a very effective evaporative cooling technology for air conditioning. Supply of chilled water to air conditioning equipments of various plant buildings and cooling tower water to important equipments for heat removal is the purpose of chilling plant at PRPD. The cooling medium used is raw water available at site. Water chemistry is maintained by make-up and blowdown. In this paper, various observations made during plant operation and equipment maintenance are discussed. The issues observed was scaling and algal growth affecting the heat transfer and availability of the equipment. Corrosion related issues were observed to be less significant. Scaling indices were calculated to predict the behavior. (author)

Forward osmosis applied to evaporative cooling make-up water

Energy Technology Data Exchange (ETDEWEB)

Nicoll, Peter; Thompson, Neil; Gray, Victoria [Modern Water plc, Guildford (United Kingdom)

2012-11-15

Modern Water is in the process of developing a number of forward osmosis based technologies, ranging from desalination to power generation. This paper outlines the progress made to date on the development and commercial deployment of a forward osmosis based process for the production of evaporative cooling tower make-up water from impaired water sources, including seawater. Evaporative cooling requires significant amounts of good quality water to replace the water lost by evaporation, drift and blowdown. This water can be provided by conventional desalination processes or by the use of tertiary treated sewage effluent. The conventional processes are well documented and understood in terms of operation and power consumption. A new process has been successfully developed and demonstrated that provides make-up water directly, using a core platform 'forward osmosis' technology. This new technology shows significant promise in allowing various raw water sources, such as seawater, to be used directly in the forward osmosis step, thus releasing the use of scarce and valuable high grade water for other more important uses. The paper presents theoretical and operational results for the process, where it is shown that the process can produce make-up water at a fraction of the operational expenditure when compared to conventional processes, in particular regarding power consumption, which in some cases may be as low as 15 % compared to competing processes. Chemical additives to the cooling water (osmotic agent) are retained within the process, thus reducing their overall consumption. Furthermore the chemistry of the cooling water does not support the growth of Legionella pneumophila. Corrosion results are also reported. (orig.)

Draining and drying process development of the Tokamak Cooling Water System of ITER

Energy Technology Data Exchange (ETDEWEB)

Kim, Seokho, E-mail: kims@ornl.gov [US ITER, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Van Hove, Walter; Ferrada, Juan [US ITER, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Di Maio, Pietro Alessandro [University of Palermo, Viale delle Scienze, Palermo 90128 (Italy); Felde, David [Reactor and Nuclear Systems Division, ORNL, Oak Ridge, TN (United States); Raphael, Mitteau; Dell’Orco, Giovanni [ITER Organization, 13067 St Paul Lez Durance (France); Berry, Jan [US ITER, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

2016-11-01

Highlights: • A thermal-hydraulic model using RELAP was developed for the ITER FW/BLK modules to determine design parameters for the nitrogen blowout flow rate and pressure. • The analysis indicates that as low as 2 MPa of pressure difference over the blanket modules will sufficiently evacuate the water in blankets. • A limited validation study indicates that the analysis yields less conservative results to compare against data collected from experiments. Therefore, the designed blow out flow of the drying system was selected with a large margin above the measured values to ensure the blow out operation. - Abstract: The ITER Organization (IO) developed a thermal-hydraulic (TH) model of the complex first wall and blanket (FW/BLK) cooling channels to determine gas flow rate and pressure required to effectively blow out the water in the FW/BLK. In addition, US ITER conducted experiments for selected geometries of FW/BLK flow channels to predict the blowout parameters. The analysis indicates that as low as 2 MPa of pressure difference over the blanket modules will ensure substantial evacuation of the water in blankets with just a few percent remaining in the blanket flow channels. A limited validation study indicates that the analysis yields less conservative results to compare against data collected from experiments. Therefore, the designed blow out flow of the drying system was selected with a large margin above the measured values to ensure the blow out operation.

Water cooled nuclear reactor

International Nuclear Information System (INIS)

1975-01-01

A description is given of a cooling water intake collector for a nuclear reactor. It includes multiple sub-collectors extending out in a generally parallel manner to each other, each one having a first end and a second one separated along their length, and multiple water outlets for connecting each one to a corresponding pressure tube of the reactor. A first end tube and a second one connect the sub-collector tubes together to their first and second ends respectively. It also includes multiple collector tubes extending transversely by crossing over the sub-collector tubes and separated from each other in the direction of these tubes. Each collector tubes has a water intake for connecting to a water pump and multiple connecting tubes separated over its length and connecting each one to the corresponding sub-collector [fr

Numerical Analysis of Rotating Pumping Flows in Inter-Coil Rotor Cavities and Short Cooling Grooves of a Generator

Directory of Open Access Journals (Sweden)

Wei Tong

2001-01-01

Full Text Available An important characteristic of wall rotating-driven flows is the tendency of fluid with high angular momentum to be flung radially outward. For a generator, the rotor rotating-driven flow, usually referred to as the rotating pumping flow, plays an important role in rotor winding cooling. In this study, three-dimensional numerical analyzes are presented for turbulent pumping flow in the inter-coil rotor cavity and short cooling grooves of a generator. Calculations of the flow field and the mass flux distribution through the grooves were carried out in a sequence of four related cases Under an isothermal condition: (a pumping flow, which is the self-generated flow resulted from the rotor pumping action; (b mixing flow, which is the combination of the ventilating flow and pumping flow, under a constant density condition; (c mixing flow, with density modeled by the ideal gas law; and (d mixing flow, with different pressure differentials applied on the system. The comparisons of the results from these cases can provide useful information regarding the impacts of the ventilating flow, gas density, and system pressure differential on the mass flux distribution in the short cooling grooves. Results show that the pumping effect is strong enough to generate the cooling flow for rotor winding cooling. Therefore, for small- or mid-size generators ventilation fans may be eliminated. It also suggests that increasing the chimney dimension can improve the distribution uniformity of mass flux through the cooling grooves.

A Mathematical Model of a Thermally Activated Roof (TAR Cooling System Using a Simplified RC-Thermal Model with Time Dependent Supply Water Temperature

Directory of Open Access Journals (Sweden)

Khalid Ahmed Joudi

2017-01-01

Full Text Available This paper presents a computer simulation model of a thermally activated roof (TAR to cool a room using cool water from a wet cooling tower. Modeling was achieved using a simplified 1-D resistance-capacitance thermal network (RC model for an infinite slab. Heat transfer from the cooling pipe network was treated as 2-D heat flow. Only a limited number of nodes were required to obtain reliable results. The use of 6th order RC-thermal model produced a set of ordinary differential equations that were solved using MATLAB - R2012a. The computer program was written to cover all possible initial conditions, material properties, TAR system geometry and hourly solar radiation. The cool water supply was considered time dependent with the variation of the ambient wet bulb temperature. Results from RC-thermal modeling were compared with experimental measurements for a second story room measuring 5.5 m x 4 m x 3 m at Amarah city/ Iraq (31.865 ˚N, 47.128 ˚E for 21 July, 2013. The roof was constructed of 200 mm concrete slab, 150 mm turf and 50 mm insulation. Galvanized 13 mm steel pipe coils were buried in the roof slab with a pipe occupation ratio of 0.12. The walls were constructed of 240 mm common brick with 10mm cement plaster on the inside and outside surfaces and 20 mm Styrofoam insulation on the inside surface and covered with PVC panel. Thermistors were used to measure the indoor and outdoor temperatures, TAR system water inlet and outlet temperatures and temperature distribution inside the concrete slab. The effect of pipe spacing and water mass flow rate were evaluated. Agreement was good between the experimental and RC-thermal model. Concrete core temperature reaches the supply water temperature faster for lower pipe spacing. Heat extracted from the space increased with water mass flow rate to an optimum of 0.0088 kg/s.m².

Fast reactor cooled by supercritical light water

Energy Technology Data Exchange (ETDEWEB)

Ishiwatari, Yuki; Mukouhara, Tami; Koshizuka, Seiichi; Oka, Yoshiaki [Tokyo Univ., Nuclear Engineering Research Lab., Tokai, Ibaraki (Japan)

2001-09-01

This report introduces the result of a feasibility study of a fast reactor cooled by supercritical light water (SCFR) with once-through cooling system. It is characterized by (1) no need of steam separator, recirculation system, or steam generator, (2) 1/7 of core flow rate compared with BWR or PWR, (3) high temperature and high pressure permits small turbine and high efficiency exceeding 44%, (4) structure and operation of major components are already experienced by LWRs or thermal power plants. Modification such as reducing blanket fuels and increasing seed fuels are made to achieve highly economic utilization of Pu and high power (2 GWe). The following restrictions were satisfied. (1) Maximum linear heat rate 39 kW/m, (2) Maximum surface temperature of Inconel cladding 620degC, (3) Negative void reactivity coefficient, (4) Fast neutron irradiation rate at the inner surface of pressure vessel less than 2.0x10{sup 19} n/cm{sup 2}. Thus the high power density of 167 MW/m{sup 3} including blanket is thought to contributes economy. The high conversion is attained to be 0.99 Pu fission residual rate by the outer radius of fuel rod of 0.88 mm. The breeding of 1.034 by Pu fission residual rate can be achieved by using briquette (tube-in-shell) type fuel structure. (K. Tsuchihashi)

Cooling water injection system

International Nuclear Information System (INIS)

Inai, Nobuhiko.

1989-01-01

In a BWR type reactor, ECCS system is constituted as a so-called stand-by system which is not used during usual operation and there is a significant discontinuity in relation with the usual system. It is extremely important that ECCS operates upon occurrence of accidents just as specified. In view of the above in the present invention, the stand-by system is disposed along the same line with the usual system. That is, a driving water supply pump for supplying driving water to a jet pump is driven by a driving mechanism. The driving mechanism drives continuously the driving water supply pump in a case if an expected accident such as loss of the function of the water supply pump, as well as during normal operation. That is, all of the water supply pump, jet pump, driving water supply pump and driving mechanism therefor are caused to operate also during normal operation. The operation of them are not initiated upon accident. Thus, the cooling water injection system can perform at high reliability to remarkably improve the plant safety. (K.M.)

WASA-BOSS. Development and application of Severe Accident Codes. Evaluation and optimization of accident management measures. Subproject D. Study on water film cooling for PWR's passive containment cooling system. Final report

Energy Technology Data Exchange (ETDEWEB)

Huang, Xi

2016-07-15

In the present study, a new phenomenological model was developed, to describe the water film flow under conditions of a passive containment cooling system (PCCS). The new model takes two different flow regimes into consideration, i.e. continuous water film and rivulets. For water film flow, the traditional Nusselt's was modified, to consider orientation angle and surface sheer stress. The transition from water film to rivulet as well as the structure of the stable rivulet at its onset point was modeled by using the minimum energy principle (MEP) combined with conservation equations. In addition, two different contact angles, i.e. advancing angle and retreating angle, were applied to take the hysteresis effect into consideration. The models of individual processes were validated as far as possible based on experimental data selected from open literature and from collaboration partner as well. With the models a new program module was developed and implemented into the COCOSYS program. The extended COCOSYS program was applied to analyze the containment behavior of the European generic containment and the performance of the passive containment cooling system ofthe AP1000. The results indicate clearly the importance of the new model and provide information for the optimization of the PCCS of AP1000.

WASA-BOSS. Development and application of Severe Accident Codes. Evaluation and optimization of accident management measures. Subproject D. Study on water film cooling for PWR's passive containment cooling system. Final report

International Nuclear Information System (INIS)

Huang, Xi

2016-07-01

In the present study, a new phenomenological model was developed, to describe the water film flow under conditions of a passive containment cooling system (PCCS). The new model takes two different flow regimes into consideration, i.e. continuous water film and rivulets. For water film flow, the traditional Nusselt's was modified, to consider orientation angle and surface sheer stress. The transition from water film to rivulet as well as the structure of the stable rivulet at its onset point was modeled by using the minimum energy principle (MEP) combined with conservation equations. In addition, two different contact angles, i.e. advancing angle and retreating angle, were applied to take the hysteresis effect into consideration. The models of individual processes were validated as far as possible based on experimental data selected from open literature and from collaboration partner as well. With the models a new program module was developed and implemented into the COCOSYS program. The extended COCOSYS program was applied to analyze the containment behavior of the European generic containment and the performance of the passive containment cooling system ofthe AP1000. The results indicate clearly the importance of the new model and provide information for the optimization of the PCCS of AP1000.

Water spray cooling technique applied on a photovoltaic panel: The performance response

International Nuclear Information System (INIS)

Nižetić, S.; Čoko, D.; Yadav, A.; Grubišić-Čabo, F.

2016-01-01

Highlights: • An experimental study was conducted on a monocrystalline photovoltaic panel (PV). • A water spray cooling technique was implemented to determine PV panel response. • The experimental results showed favorable cooling effect on the panel performance. • A feasibility aspect of the water spray cooling technique was also proven. - Abstract: This paper presents an alternative cooling technique for photovoltaic (PV) panels that includes a water spray application over panel surfaces. An alternative cooling technique in the sense that both sides of the PV panel were cooled simultaneously, to investigate the total water spray cooling effect on the PV panel performance in circumstances of peak solar irradiation levels. A specific experimental setup was elaborated in detail and the developed cooling system for the PV panel was tested in a geographical location with a typical Mediterranean climate. The experimental result shows that it is possible to achieve a maximal total increase of 16.3% (effective 7.7%) in electric power output and a total increase of 14.1% (effective 5.9%) in PV panel electrical efficiency by using the proposed cooling technique in circumstances of peak solar irradiation. Furthermore, it was also possible to decrease panel temperature from an average 54 °C (non-cooled PV panel) to 24 °C in the case of simultaneous front and backside PV panel cooling. Economic feasibility was also determined for of the proposed water spray cooling technique, where the main advantage of the analyzed cooling technique is regarding the PV panel’s surface and its self-cleaning effect, which additionally acts as a booster to the average delivered electricity.

Evaluation of a Design Concept for the Combined Air-water Passive Cooling PAFS+

International Nuclear Information System (INIS)

Bae, Sung Won; Kwon, Taesoon

2014-01-01

The APR+ system provides the Passive Auxiliary Feed-water System (PAFS) for the passive cooling capability. However, the current design requirement for working time for the PAFS is about 8 hours only. Thus, current working time of PAFS can not meet the required 72 hours cooling capability for the long term SBO situation. To meet the 72 hours cooling, the pool capacity should be almost 3∼4 times larger than that of current water cooling tank. In order to continue the PAFS operation for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility study on the combined passive air-water cooling system. Figure 1 and 2 show the conceptual difference of the PAFS and combined passive air-water cooling system, respectively. Simple performance evaluation of the passive air cooling heat exchanger has been conducted by the MARS calculation. For the postulated FLB scenario, 4800 heat exchanger tubes and 5 m/s air velocity are not sufficient to sustain the PCCT pool level for 72 hour cooling. Further works on the system design and performance enhancing plan are required to fulfill the 72 hours long term passive cooling

The effects of high-Ca hardness water treatment for secondary cooling water in HANARO

International Nuclear Information System (INIS)

Kang, T. J.; Park, Y. C.; Hwang, S. R.; Lim, I. C.; Choi, H. Y.

2003-01-01

Water-quality control of the second cooling system in HANARO has been altered from low Ca-hardness treatment to high Ca-hardness treatment since March, 2001. High Ca-hardness water treatment in HANARO is to maintain the calcium hardness around 12 by minimizing the blowdown of secondary cooling water. This paper describes the effect of cost reduction after change of water-quility treatment method. The result shows that the cost of the water could be reduced by 25% using the pond water in KAERI. The amount and cost for the chemical agent could be reduced by 40% and 10% respectively

Supercritical-pressure light water cooled reactors

CERN Document Server

Oka, Yoshiaki

2014-01-01

This book focuses on the latest reactor concepts, single pass core and experimental findings in thermal hydraulics, materials, corrosion, and water chemistry. It highlights research on supercritical-pressure light water cooled reactors (SCWRs), one of the Generation IV reactors that are studied around the world. This book includes cladding material development and experimental findings on heat transfer, corrosion and water chemistry. The work presented here will help readers to understand the fundamental elements of reactor design and analysis methods, thermal hydraulics, materials and water

Radionuclides behaviour in the silts-water system of a cooling pond

International Nuclear Information System (INIS)

Ol'khovik, Yu.A.; Kostyuchenko, N.G.; Koromyslichenko, T.I.

1989-01-01

As a result of the Chernobyl' accident a considerable amount of radioisotopes (1-5x10 5 Ci) concentrated in a cooling pond. A year later the accident a level of water contamination decreased by 2 orders, whereas the radionuclide distribution changed perceptibly. Processes of water self-decontamination in the cooling pond were considered. A forecast of water radiactivity level in the cooling pond in the summer of 1988 was made. 3 refs.; 1 refs.; 2 tabs

Pavement-Watering for Cooling the Built Environment: A Review

OpenAIRE

Hendel , Martin

2016-01-01

Pavement-watering is being considered by decision-makers in many cities as a means of cooling the built environment and of adapting to rising extreme heat events due to climate change. In this article we review the existing literature on the topic of pavement-watering. We first focus on the methodological choices made in the literature, including study approach and scale, watering methods used as well as how results are analyzed. We then discuss the cooling effects reported, separating micro-...

A powerful way of cooling computer chip using liquid metal with low melting point as the cooling fluid

Energy Technology Data Exchange (ETDEWEB)

Li Teng; Lv Yong-Gang [Chinese Academy of Sciences, Beijing (China). Cryogenic Lab.; Chinese Academy of Sciences, Beijing (China). Graduate School; Liu Jing; Zhou Yi-Xin [Chinese Academy of Sciences, Beijing (China). Cryogenic Lab.

2006-12-15

With the improvement of computational speed, thermal management becomes a serious concern in computer system. CPU chips are squeezing into tighter and tighter spaces with no more room for heat to escape. Total power-dissipation levels now reside about 110 W, and peak power densities are reaching 400-500 W/mm{sup 2} and are still steadily climbing. As a result, higher performance and greater reliability are extremely tough to attain. But since the standard conduction and forced-air convection techniques no longer be able to provide adequate cooling for sophisticated electronic systems, new solutions are being looked into liquid cooling, thermoelectric cooling, heat pipes, and vapor chambers. In this paper, we investigated a novel method to significantly lower the chip temperature using liquid metal with low melting point as the cooling fluid. The liquid gallium was particularly adopted to test the feasibility of this cooling approach, due to its low melting point at 29.7 C, high thermal conductivity and heat capacity. A series of experiments with different flow rates and heat dissipation rates were performed. The cooling capacity and reliability of the liquid metal were compared with that of the water-cooling and very attractive results were obtained. Finally, a general criterion was introduced to evaluate the cooling performance difference between the liquid metal cooling and the water-cooling. The results indicate that the temperature of the computer chip can be significantly reduced with the increasing flow rate of liquid gallium, which suggests that an even higher power dissipation density can be achieved with a large flow of liquid gallium and large area of heat dissipation. The concept discussed in this paper is expected to provide a powerful cooling strategy for the notebook PC, desktop PC and large computer. It can also be extended to more wide area involved with thermal management on high heat generation rate. (orig.)

Determination of mixture coefficients in tests simulating channels of a fuel assembly in a water cooled reactor

International Nuclear Information System (INIS)

Ferreira, W.R.

1983-09-01

Here, the mixture coefficients are determined in tests which simulate two symmetric and two assymetric coolant channels of a water cooled reactor. It was studies the effects of coolant flow and of the distance among the coolant channels on these coefficients. The technique used to determine the mixture coefficients was to introduce a tracer (methylene blue) into the flow. The determination of the tracer concentration at the end of the channels was made by means of spectrophotometric analysis. (author)

Tests of cooling water pumps at Dukovany nuclear power plant

International Nuclear Information System (INIS)

Travnicek, J.

1986-01-01

Tests were performed to examine the operating conditions of the 1600 BQDV cooling pumps of the main coolant circuit of unit 1 of the Dukovany nuclear power plant. For the pumps, the performance was tested in the permissible operating range, points were measured below this range and the guaranteed operating point was verified. Pump efficiency was calculated from the measured values. The discussion of the measurement of parameters has not yet been finished because the obtained values of the amount delivered and thus of the pump efficiency were not up to expectation in all detail. It was also found that for obtaining the guaranteed flow the pump impeller had to be opened to 5deg -5.5deg instead of the declared 3deg. Also tested were pump transients, including the start of the pump, its stop, the operation and failure of one of the two pumps. In these tests, pressures were also measured at the inlet and the outlet of the inner part of the TG 11 turbine condenser. It was shown that the time course and the pressure course of the processes were acceptable. In addition to these tests, pressure losses in the condenser and the cooling water flow through the feed pump electromotor cooler wre tested for the case of a failure of one of the two pumps. (E.S.)

Four foot septifoil cooling experiment unrestricted inlet/outlet case

International Nuclear Information System (INIS)

Foti, D.J.; Randolph, H.W.; Geiger, G.T.; Verebelyi, D.T.; Wooten, L.A.

1992-02-01

The ability to predict the behavior of reactor components to varying coolant flow scenarios constitutes a necessary skill for assessing reactor safety. One tool for performing these calculations is the Transient Reactor Analysis Code (TRAC). In order to benchmark the code, the Safety Analysis Group of SRL requested the Equipment Engineering Section (EES) of SRL to conduct a series of experiments to provide measurements of cooling parameters in a well defined physical system utilizing SRS reactor components. The configuration selected consisted of a short length of septifoil with both top and bottom fittings containing five simulated control rods in an open-quotes unseatedclose quotes configuration. Varying power levels were to be supplied to the rods with 3.5 kilowatts per foot the value targeted for modelling during the computer runs. The septifoil segment was to be operated with no forced flow in order to evaluate thermal-hydraulic cooling. Parameters to be measured for comparison with code predictions were basic cooling phenomena, incidence of film boiling, water flow rate, pressure rise, and ratio of heat transfer through the wall of the assembly vs. heat transfer to axial water flow through the assembly. This report documents testing done with unimpeded flow into and out of the septifoil in order to assess basic cooling phenomena, incidence of film boiling and pressure rise. Previous tests have evaluated water flow rate and the ratio of axial to azimuthal heat transfer

Water conservation and improved production efficiency using closed-loop evaporative cooling systems

Energy Technology Data Exchange (ETDEWEB)

Marchetta, C. [Niagara Blower Co., Buffalo, NY (United States)

2009-07-01

This paper described wet surface air coolers (WSAC) that can be used in refineries and hydrocarbon processing plants to address water use issues. These closed-loop evaporative cooling systems are a cost-effective technology for both heat transfer and water conservation. WSACs can help deliver required cooling water temperatures and improve plant performance while using water streams currently considered to be unusable with conventional towers and heat exchangers. WSACs are versatile and can provide solutions to water use, water quality, and outlet temperature. The benefits of the WSAC include capital cost savings, reduced system pressures, lower carbon footprint, and the ability to use poor quality water as makeup. Water makeup can be blowdown from other equipment, plant effluent, reclaimed water, produced water, flue gas desulphurization (FGD) wastewater, and even seawater. Units can be manufactured with a wide variety of materials depending on water quality, water treatment, and cycles of concentration. This paper also provided comparisons to other alternative technologies, capital and operating cost savings, and site specific case studies. Two other system designs can accommodate closed-loop heat transfer applications, notably an open tower with a heat exchanger and a dry, air-cooled system. A WSAC system is an efficient and effective heat rejection technology for several reasons. The WSAC cooler or condenser utilizes latent cooling, which is far more efficient than sensible cooling. This means that a WSAC system can cool the same heat load with a smaller footprint than all-dry systems. 6 figs.

Cooling tower make-up water processing for nuclear power plants: a comparison

Energy Technology Data Exchange (ETDEWEB)

Andres, O; Flunkert, F; Hampel, G; Schiffers, A [Rheinisch-Westfaelisches Elektrizitaetswerk A.G., Essen (Germany, F.R.)

1977-01-01

In water-cooled nuclear power plants, 1 to 2% of the total investment costs go to cooling tower make-up water processing. The crude water taken from rivers or stationary waters for cooling must be sufficiently purified regarding its content of solids, carbonate hardness and corrosive components so as to guarantee an operation free of disturbances. At the same time, the processing methods must be selected for operational-economic reasons in such a manner that waste water and waste problems are kept small regarding environmental protection. The various parameters described have a decisive influence on the processing methods of the crude water, individual processes (filtration, sedimentation, decarbonization) are described, circuit possibilities for cooling water systems are compared and the various processes are analyzed and compared with regard to profitableness and environmental compatability.

Specific features of phase distribution in a draught part of the tank type boiling water cooled reactor

International Nuclear Information System (INIS)

Fedulin, V.N.; Bartolomej, G.G.; Solodkij, V.A.; Shmelev, V.E.

1984-01-01

The results of experimental investigation of the two-phase flow structure in a draught part of the VK-50 boiling water cooled reactor are presented. A qualitative physical model of steam-water mixture flow in the large diameter draught part is suggested. It is shown that for hydrodynamically unstable two-phase flows a considerable nonuniformity in steam content distribution over the draught part volume which determines the possibility of the recirculating coolant flow formation in the peripheral zone is observed. At the draught part inlet the radial distribution of steam content is determined by the complex effects of power distribution and coolant flow rate change over the core radius. The flow structure in the lower section of the draught part adjoining to the core is determined to a considerable degree by a coolant jet outflow from fuel assembly (FA) nozzels Jet height depends on the velocity of outgoing two-phase flow, working pressure and hydrodynamics of the draught part. The jet height does not exceed 0.4 m for the K-50 reactor. Due to the increased steam outflow from the central FAs and the existence of radial pressure gradient the water-steam mixture is turned from the draught part periphery to its central part, where accelerated water steam flow with an increased steam content is formed. When a certain height is achieved a graduel expansion of the water-steam flow begins leading to equalizing the steam content over the draught part cross section

Numerical investigation of supercritical water-cooled nuclear reactor in horizontal rod bundles

Energy Technology Data Exchange (ETDEWEB)

Shang Zhi, E-mail: shangzhi@tsinghua.org.c [Faculty of Engineering, Kingston University, London SW15 3DW (United Kingdom); Science and Technology Facilities Council, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Lo, Simon, E-mail: simon.lo@uk.cd-adapco.co [CD-adapco, Trident House, Basil Hill Road, Didcot OX11 7HJ (United Kingdom)

2010-04-15

The commercial CFD code STAR-CD v4.02 is used as a numerical simulation tool for flows in the supercritical water-cooled nuclear reactor (SCWR). The basic heat transfer element in the reactor core can be considered as round rods and rod bundles. Reactors with vertical or horizontal flow in the core can be found. In vertically oriented core, symmetric characters of flow and heat transfer can be found and two-dimensional analyses are often performed. However, in horizontally oriented core the flow and heat transfer are fully three-dimensional due to the buoyancy effect. In this paper, horizontal rods and rod bundles at SCWR conditions are studied. Special STAR-CD subroutines were developed by the authors to correctly represent the dramatic change in physical properties of the supercritical water with temperature. In the rod bundle simulations, it is found that the geometry and orientation of the rod bundle have strong effects on the wall temperature distributions and heat transfers. In one orientation the square bundle has a higher wall temperature difference than other bundles. However, when the bundles are rotated by 90 deg. the highest wall temperature difference is found in the hexagon bundle. Similar analysis could be useful in design and safety studies to obtain optimum fuel rod arrangement in a SCWR.

Thermal-hydraulic analysis on the whole module of water cooled ceramic breeder blanket for CFETR

Energy Technology Data Exchange (ETDEWEB)

Jiang, Kecheng; Ma, Xuebin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230027 (China); Cheng, Xiaoman [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Lin, Shuang [University of Science and Technology of China, Hefei, Anhui, 230027 (China); Huang, Kai [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Liu, Songlin, E-mail: slliu@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230027 (China)

2016-11-15

Highlights: • The 3D thermal hydraulic analysis on the whole module of WCCB is performed by CFD method. • Temperature field and mass flow distribution have been obtained. • The design of WCCB is reasonable from the perspective of thermal-hydraulics. • The scheme for further optimization has been proposed. - Abstract: The Water Cooled Ceramic Breeder blanket (WCCB) is being researched for Chinese Fusion Engineering Test Reactor (CFETR). The thermal-hydraulic analysis is essential because the blanket should remove the high heat flux from the plasma and the volumetric heat generated by neutrons. In this paper, the detailed three dimensional (3D) thermal hydraulic analysis on the whole module of WCCB blanket has been performed by Computational Fluid Dynamics (CFD) method, which is capable of solving conjugate heat transfer between solid structure and fluid. The main results, including temperature field, distribution of mass flow rate and coolant pressure drop, have been calculated simultaneously. These provides beneficial guidance data for the further structural optimization and for the design arrangement of primary and secondary circuit. Under the total heat source of 1.23 MW, the coolant mass flow rate of 5.457 kg/s is required to make coolant water corresponding to the Pressurized Water Reactor (PWR) condition (15.5 MPa, 285 °C–325 °C), generating the total coolant pressure drop (△P) of 0.467 MPa. The results show that the present structural design can make all the materials effectively cooled to the allowable temperature range, except for a few small modifications on the both sides of FW. The main components, including the first wall (FW), cooling plates (CPs), side wall (SWs)&stiffening plates (SPs) and the manifold(1–4), dominate 4.7%/41.7%/13%/40.6% of the total pressure drop, respectively. Additionally, the mass flow rate of each channel has been obtained, showing the peak relative deviation of 3.4% and 2% from the average for the paratactic

Numerical analysis of hypersonic turbulent film cooling flows

Science.gov (United States)

Chen, Y. S.; Chen, C. P.; Wei, H.

1992-01-01

As a building block, numerical capabilities for predicting heat flux and turbulent flowfields of hypersonic vehicles require extensive model validations. Computational procedures for calculating turbulent flows and heat fluxes for supersonic film cooling with parallel slot injections are described in this study. Two injectant mass flow rates with matched and unmatched pressure conditions using the database of Holden et al. (1990) are considered. To avoid uncertainties associated with the boundary conditions in testing turbulence models, detailed three-dimensional flowfields of the injection nozzle were calculated. Two computational fluid dynamics codes, GASP and FDNS, with the algebraic Baldwin-Lomax and k-epsilon models with compressibility corrections were used. It was found that the B-L model which resolves near-wall viscous sublayer is very sensitive to the inlet boundary conditions at the nozzle exit face. The k-epsilon models with improved wall functions are less sensitive to the inlet boundary conditions. The testings show that compressibility corrections are necessary for the k-epsilon model to realistically predict the heat fluxes of the hypersonic film cooling problems.

Innovative technologies for Faraday shield cooling

International Nuclear Information System (INIS)

Rosenfeld, J.H.; Lindemuth, J.E.; North, M.T.; Goulding, R.H.

1995-01-01

Alternative advanced technologies are being evaluated for use in cooling the Faraday shields used for protection of ion cyclotron range of frequencies (ICR) antennae in Tokamaks. Two approaches currently under evaluation include heat pipe cooling and gas cooling. A Monel/water heat pipe cooled Faraday shield has been successfully demonstrated. Heat pipe cooling offers the advantage of reducing the amount of water discharged into the Tokamak in the event of a tube weld failure. The device was recently tested on an antenna at Oak Ridge National Laboratory. The heat pipe design uses inclined water heat pipes with warm water condensers located outside of the plasma chamber. This approach can passively remove absorbed heat fluxes in excess of 200 W/cm 2 ;. Helium-cooled Faraday shields are also being evaluated. This approach offers the advantage of no liquid discharge into the Tokamak in the event of a tube failure. Innovative internal cooling structures based on porous metal cooling are being used to develop a helium-cooled Faraday shield structure. This approach can dissipate the high heat fluxes typical of Faraday shield applications while minimizing the required helium blower power. Preliminary analysis shows that nominal helium flow and pressure drop can sufficiently cool a Faraday shield in typical applications. Plans are in progress to fabricate and test prototype hardware based on this approach

Two-phase flow in the cooling circuit of a cryogenic rocket engine

Science.gov (United States)

Preclik, D.

1992-07-01

Transient two-phase flow was investigated for the hydrogen cooling circuit of the HM7 rocket engine. The nuclear reactor code ATHLET/THESEUS was adapted to cryogenics and applied to both principal and prototype experiments for validation and simulation purposes. The cooling circuit two-phase flow simulation focused on the hydrogen prechilling and pump transient phase prior to ignition. Both a single- and a multichannel model were designed and employed for a valve leakage flow, a nominal prechilling flow, and a prechilling with a subsequent pump-transient flow. The latter case was performed in order to evaluate the difference between a nominal and a delayed turbo-pump start-up. It was found that an extension of the nominal prechilling sequence in the order of 1 second is sufficient to finally provide for liquid injection conditions of hydrogen which, as commonly known, is undesirable for smooth ignition and engine starting transients.