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Sample records for chromel

  1. The thermoelectric power of chromel at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, J.A. [Valle Univ., Cali (Colombia). Dept. de Fisica; Correa, H. [Tecnologia Electronica, Univ. del Quindio, Armenia (Colombia); Jurado, J.F. [Dept. de Fisica, Univ. Autonoma de Occidente, Cali (Colombia); Vargas, R.A.

    2000-07-01

    By using the AC calorimetric technique we have developed a high-resolution experimental setup to study the thermoelectric power in a temperature range of 77 to 300 K. The system was tested using a chromel alloy (90% nickel, 10% chromium). Optical radiation was used to heat the sample periodically with a frequency of {omega}/2{pi} = 1.5 Hz which induces temperature modulation T{sub ac} in one end of the sample. The induced emf V{sub ac}(T) between the illuminated and the dark sides of the sample was measured. The thermoelectric power S(T) was calculated from the relation V{sub ac}/T{sub ac} whose data points indicate an anomaly near 225 K. The temperature region of this anomaly agrees with that of the previously reported specific heat anomaly of chromel which is associated with the para- to ferroelectric phase transition in this Ni alloy. (orig.)

  2. Application of the method of thermo-power in diagnosing fatigue strength and intergrain corrosion

    Directory of Open Access Journals (Sweden)

    Dominjuk T.I

    2009-04-01

    Full Text Available In area of flat defect, predefined a gradient tireless - corrosive tensions, a double electric layer, conditioned the spatial redistribution of electronic closeness, is formed. It shows up a local rejection mikro-thermo-power at use of heating edge of tungsten thermocouple. Test approbation of method is conducted on the deformed chromel.

  3. Abstracts of the International Symposium on Gas Kinetics (9th) Held in Talence (France) on 20-25 July 1986.

    Science.gov (United States)

    1986-07-25

    tile Fases was measured by ineans a chromel-alutfiel thermoc oupl, mounted ir the tip of the moveable injector. Flow rates of difiutett loactants were...decompose with loss of CH3 and thus cannot lead to inhibition. 13 By making sensible (we hopel) assumptions about the reactivity of C2 H5 towards

  4. Probe Measures Fouling As In Heat Exchangers

    Science.gov (United States)

    Marner, Wilbur J.; Macdavid, Kenton S.

    1990-01-01

    Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

  5. Proceedings of the International Symposium on Diamond Materials Held in Washington, DC on 5-10 May 1991. Volume 91-8

    Science.gov (United States)

    1991-05-01

    A.M. Bonnot, T. Lopez-Rios, B. Mathis & J. Leroy CHARACTERIZATION OF DC PLASMAS FOR THE CONTROL 290 OF DIAMOND DEPOSITION L.S. Plano , D.A. Stevenson...589 M.I. Landstrass, M.A. Plano , & D. Moyer THE GROWTH AND SOME PROPERTIES OF DIAMOND FILMS 597 OF P- AND N-TYPE CONDUCTIVITY OBTAINED BY...temperature was measured by a 0.125mm diame- ter chromel/alumel thermocouple in intimate contact with the crystal. The thermocou- pie was threaded through a

  6. Evaluation of miniature single-wire sheathed thermocouples for turbine blade temperature measurement

    Science.gov (United States)

    Hollanda, R.

    1979-01-01

    Chromel Alumel thermocouples were used, with sheath diameters of 0.15 and 0.25 mm. Tests were conducted at temperatures ranging from 750 to 1250 K. Both steady state and thermal cycling tests were performed for times up to 200 hours. Initial testing was performed in a low velocity gas stream for long time periods using a Meker-type burner. Additional testing was done in a high velocity gas stream for short time periods using a hot gas tunnel and also in a J75 jet engine. A total of eleven 0.15 mm diameter thermocouples and six 0.25 mm diameter thermocouples were tested. Drift rates up to 2.5% in 10 hours were observed. Photomicrographs show that this design is near the limit of miniaturization based on present manufacturing capabilities. Results indicate that the effects of miniaturization on reliability and accuracy must be considered when choosing thermocouples for a particular application.

  7. Resonant Thermoelectric Nanophotonics

    CERN Document Server

    Mauser, Kelly W; Kim, Seyoon; Fleischman, Dagny; Atwater, Harry A

    2016-01-01

    Photodetectors are typically based on photocurrent generation from electron-hole pairs in semiconductor structures and on bolometry for wavelengths that are below bandgap absorption. In both cases, resonant plasmonic and nanophotonic structures have been successfully used to enhance performance. In this work, we demonstrate subwavelength thermoelectric nanostructures designed for resonant spectrally selective absorption, which creates large enough localized temperature gradients to generate easily measureable thermoelectric voltages. We show that such structures are tunable and are capable of highly wavelength specific detection, with an input power responsivity of up to 119 V/W (referenced to incident illumination), and response times of nearly 3 kHz, by combining resonant absorption and thermoelectric junctions within a single structure, yielding a bandgap-independent photodetection mechanism. We report results for both resonant nanophotonic bismuth telluride-antimony telluride structures and chromel-alumel...

  8. Miniature sheathed thermocouples for turbine blade temperature measurement

    Science.gov (United States)

    Holanda, R.; Glawe, G. E.; Krause, L. N.

    1974-01-01

    An investigation was made of sheathed thermocouples for turbine blade temperature measurements. Tests were performed on the Chromel-Alumel sheathed thermocouples with both two-wire and single-wire configurations. Sheath diameters ranged from 0.25 to 0.76 mm, and temperatures ranged from 1080 to 1250 K. Both steady-state and thermal cycling tests were performed for times up to 450 hr. Special-order and commercial-grade thermocouples were tested. The tests showed that special-order single-wire sheathed thermocouples can be obtained that are reliable and accurate with diameters as small as 0.25 mm. However, all samples of 0.25-mm-diameter sheathed commercial-grade two-wire and single-wire thermocouples that were tested showed unacceptable drift rates for long-duration engine testing programs. The drift rates were about 1 percent in 10 hr. A thermocouple drift test is recommended in addition to the normal acceptance tests in order to select reliable miniature sheathed thermocouples for turbine blade applications.

  9. Heat transfer characteristics of igniter output plumes

    Science.gov (United States)

    Evans, N. A.; Durand, N. A.

    Seven types of pyrotechnic igniters were each mounted at one end of a closed cylindrical bore hole representative of the center hole in a thermal battery. Measurements of local bore wall temperature, T(sub w), using commercially available, fast response (10 microsec) sheathed chromel-constantan thermocouples allowed calculation of local heat transfer rates, q, and wall heat flows, Q. The principal charge constituents of all these igniters were titanium and potassium perchlorate, while three types also contained barium styphnate as an ignition sensitizer. Igniter closure disc materials included glass-ceramic, glass, metal (plain, scored, with and without capture cone), and kapton/RTV. All igniters produced the lowest values of T(sub w) and q at the beginning of the bore, and, except for the igniter with the kapton/RTV closure disc, these quantities increased with distance along the bore. For igniters containing only titanium/potassium perchlorate, the rates of increase of Q along the bore length, compared with those for T(sub w) and q, were generally lower and more variable. The inclusion of barium styphnate produced rates of change in Q that were essentially constant to the end of the bore. The highest overall average wall temperatures were achieved by two igniter types with metal closure discs and no capture cone. No clear correlation was established between peak bore pressure and maximum wall temperature.

  10. Heat transfer characteristics of igniter output plumes

    Energy Technology Data Exchange (ETDEWEB)

    Evans, N.A.; Durand, N.A.

    1989-01-01

    Seven types of pyrotechnic igniters were each mounted at one end of a closed cylindrical bore hole representative of the center hole in a thermal battery. Measurements of local bore wall temperature, T/sub w/, using commercially available, fast response (10 /mu/sec) sheathed chromel-constantan thermocouples allowed calculation of local heat transfer rates, q, and wall heat flows, Q. The principal charge constituents of all these igniters were titanium and potassium perchlorate, while three types also contained barium styphnate as an ignition sensitizer. Igniter closure disc materials included glass-ceramic, glass, metal (plain, scored, with and without capture cone), and kapton/RTV. All igniters produced the lowest values of T/sub w/ and q at the beginning of the bore, and, except for the igniter with the kapton/RTV closure disc, these quantities increased with distance along the bore. For igniters containing only titanium/potassium perchlorate, the rates of increase of Q along the bore length, compared with those for T/sub w/ and q, were generally lower and more variable. The inclusion of barium styphnate produced rates of change in Q that were essentially constant to the end of the bore. The highest overall average wall temperatures were achieved by two igniter types with metal closure discs and no capture cone. No clear correlation was established between peak bore pressure and maximum wall temperature. 3 refs., 8 figs., 1 tab.

  11. Cell integrated multi-junction thermocouple array for solid oxide fuel cell temperature sensing: N+1 architecture

    Science.gov (United States)

    Ranaweera, Manoj; Kim, Jung-Sik

    2016-05-01

    Understanding the cell temperature distribution of solid oxide fuel cell (SOFC) stacks during normal operation has multifaceted advantages in performance and degradation studies. Present efforts on measuring temperature from operating SOFCs measure only the gas channel temperature and do not reveal the cell level temperature distribution, which is more important for understanding a cell's performance and its temperature-related degradation. The authors propose a cell-integrated, multi-junction thermocouple array for in-situ cell surface temperature monitoring of an operational SOFC. The proposed thermocouple array requires far fewer numbers of thermoelements than that required by sets of thermocouples for the same number of temperature sensing points. Hence, the proposed array causes lower disturbance to cell performance than thermocouples. The thermoelement array was sputter deposited on the cathode of a commercial SOFC using alumel (Ni:Al:Mn:Si - 95:2:2:1 by wt.) and chromel (Ni:Cr - 90:10 by wt.). The thermocouple array was tested in a furnace over the entire operating temperature range of a typical SOFC. The individual sensing points of the array were shown to measure temperature independently from each other with equivalent accuracy to a thermocouple. Thus, the concept of multi-junction thermocouples is experimentally validated and its stability on a porous SOFC cathode is confirmed.

  12. Calculation of the Uncertainty of Cheap Metal Thermocouple%廉金属热电偶的不确定度计算

    Institute of Scientific and Technical Information of China (English)

    刘晔

    2016-01-01

    目前用量最大的廉金属热电偶是镍铬-镍硅热电偶(K型热电偶),为保证计量性能的准确可靠,采用双极法对其进行检定,用一等标准铂铑10-铂热电偶检定一支K型II级热电偶,检定点选取1000℃。文章重点介绍了该检定方法和示值误差的不确定度评定。%The current most widely used cheap metal thermocouple is chromel-silicel thermocouple (K type thermocouple). In order to ensure the accuracy and reliability of the calculation, we use bipolar method for its verification. The first standard Pt-Rh 10-platinum thermocouple is used to verify a K type Class II thermocouple, and the verification point is 1000℃. This paper mainly introduces the uncertainty evaluation of this verification method and the indication error.

  13. [Perforated duodenal diverticula. Case report and treatment options].

    Science.gov (United States)

    Guardado-Bermúdez, Fernando; Ardisson-Zamora, Fernando Josafat; Rojas-González, Juan Daniel; Medina-Benítez, Alberto; Corona-Suárez, Fernando

    2013-01-01

    Antecedentes: los divertículos duodenales los describió por primera vez Chromel en 1710. El divertículo duodenal es el segundo sitio más frecuente de divertículos en el tubo digestivo, el diagnóstico se limita a los casos con complicaciones y síntomas. Los divertículos duodenales se localizan en 10- 67% en la segunda porción del duodeno. Su hallazgo en la mayoría de los casos es incidental. Cerca de 90% de los pacientes cursan asintomáticos y sólo se manifiestan cuando sobrevienen las complicaciones, como la hemorragia digestiva y la perforación. Caso clínico: paciente femenina de 78 años de edad, que acudió al hospital debido a disnea de medianos esfuerzos y epigastralgia moderada, distensión abdominal, constipación y dificultad para canalizar gases. La laparotomía identificó un divertículo duodenal con perforación en su cúpula de 5 mm que dio pie a la realización de la diverticulectomía. Conclusiones: el diagnóstico de divertículo duodenal, como etiología de abdomen agudo, debe contemplarse en cualquier diagnóstico diferencial con cuadro de abdomen agudo, apoyados siempre en la imagenología y endoscopia. El tratamiento quirúrgico del divertículo duodenal, en especial su resección, sigue siendo la recomendación dirigida a la menor morbilidad y mejor recuperación.

  14. Uncertainty analysis of thermocouple measurements used in normal and abnormal thermal environment experiments at Sandia's Radiant Heat Facility and Lurance Canyon Burn Site.

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, James Thomas

    2004-04-01

    It would not be possible to confidently qualify weapon systems performance or validate computer codes without knowing the uncertainty of the experimental data used. This report provides uncertainty estimates associated with thermocouple data for temperature measurements from two of Sandia's large-scale thermal facilities. These two facilities (the Radiant Heat Facility (RHF) and the Lurance Canyon Burn Site (LCBS)) routinely gather data from normal and abnormal thermal environment experiments. They are managed by Fire Science & Technology Department 09132. Uncertainty analyses were performed for several thermocouple (TC) data acquisition systems (DASs) used at the RHF and LCBS. These analyses apply to Type K, chromel-alumel thermocouples of various types: fiberglass sheathed TC wire, mineral-insulated, metal-sheathed (MIMS) TC assemblies, and are easily extended to other TC materials (e.g., copper-constantan). Several DASs were analyzed: (1) A Hewlett-Packard (HP) 3852A system, and (2) several National Instrument (NI) systems. The uncertainty analyses were performed on the entire system from the TC to the DAS output file. Uncertainty sources include TC mounting errors, ANSI standard calibration uncertainty for Type K TC wire, potential errors due to temperature gradients inside connectors, extension wire uncertainty, DAS hardware uncertainties including noise, common mode rejection ratio, digital voltmeter accuracy, mV to temperature conversion, analog to digital conversion, and other possible sources. Typical results for 'normal' environments (e.g., maximum of 300-400 K) showed the total uncertainty to be about {+-}1% of the reading in absolute temperature. In high temperature or high heat flux ('abnormal') thermal environments, total uncertainties range up to {+-}2-3% of the reading (maximum of 1300 K). The higher uncertainties in abnormal thermal environments are caused by increased errors due to the effects of imperfect TC attachment to

  15. Performance assessment of thermal sensors during short-duration convective surface heating measurements

    Science.gov (United States)

    Sahoo, Niranjan; Kumar, Rakesh

    2016-09-01

    The determination of convective surface heating is a very crucial parameter in high speed flow environment. Most of the ground based facilities in this domain have short duration experimental time scale (~milliseconds) of measurements. In these facilities, the calorimetric heat transfer sensors such as thin film gauges (TFGs) and coaxial surface junction thermocouple (CSJT) are quite effective temperature detectors. They have thickness in the range of few microns and have capability of responding in microsecond time scale. The temperature coefficient of resistance (TCR) and the sensitivity are calibration parameter indicators that show the linear change in the resistance of the gauge as a function of temperature. In the present investigation, three of types of heat transfer gauges are fabricated in the laboratory namely, TFG made out of platinum, TFG made out of platinum mixed with CNT and chromel-alumel surface junction coaxial thermocouple (K-type). The calibration parameters of the gauges are determined though oil-bath experiments. The average value TCR and sensitivity of platinum TFG is found to be 0.0024 K-1 and 465 μV/K, while similar values of CSJT are obtained as, 0.064 K-1 and 40.5 μV/K, respectively. The TFG made out of platinum mixed with CNT (5 % by mass) shows the enhancement of TCR as well as sensitivity and the corresponding values are 0.0034 K-1 and 735 μV/K, respectively. The relative performances of heat transfer gauges are compared in a simple laboratory scale experiment in which the gauges are exposed to a sudden step heat load in convection mode for the time duration of 200 ms. The surface heat fluxes are predicted from the temperature history through one dimensional heat conduction modeling. While comparing the experimental results, it is seen that prediction of surface heat flux from all the heat transfer gauges are within the range of ±4 %.

  16. A Study of the Behavior Characteristics for K-type Thermocouple

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Songhae; Kim, Yongsik; Lee, Sooill [KHNP Central Research Institute, Daejeon (Korea, Republic of); Kim, Sungjin [Woojin inc., Osan (Korea, Republic of); Lyou, Jooon [Chungnam National Univ., Daejeon (Korea, Republic of)

    2014-05-15

    K-type thermocouple is widely used in nuclear power plants (NPP) and they provide reliable service. Generally, the thermocouple assembly is the finished product and usually only nondestructive tests are performed on the assembly, whereas destructive tests are confined to selected bulk cable specimens. This K-type thermocouple has been used representatively in the In-Core Instrument Assembly (ICI) in the nuclear power plants. The ICI consists of five rhodium emitter detectors that provide information on the thermal power for the core and one K-type thermocouple made with two cables (Chromel-Alumel) that provides the temperature of core exit (CET). Generally, the quantity of the ICI is absolutely different according to the number of fuel assemblies in the NPP. In the case of SKN 3 and 4, they were designed to the 61 ICI to provide information on the core cooling to the inadequate core cooling monitoring system (ICCMS). This measured temperature could be also used to check the entry condition of severe accidents. The technology of the TFDR is a generic skill to detect the fault position of the cable. In-core Instruments (ICIs) were used to detect the Core Exit Temperature (CET) in a reactor. This measured temperature was also used to check the entry condition of severe accidents. However, if a serious accident occurs, the upper portion of the core is damaged. This instrument has not been available. This paper illustrates the estimation possibility for the status of molten core through the high-temperature characteristics test of k-type thermocouple. It turns out that it is possible to measure the k-type thermocouple up to 1350 .deg. C degrees before melting during insertion into the melting furnace. Additionally, in order to measure a high temperature of 2000 .deg. C or more, the replacement possibility of k-type thermocouple was evaluated. However the tungsten-rhenium thermocouple is impossible to use in the detection of temperature at the in-core because of the

  17. Study of the heat-transfer crisis on heat-release surfaces of annular channels with swirl and transit flows

    Science.gov (United States)

    Boltenko, E. A.

    2016-10-01

    The results of the experimental study of the heat-transfer crisis on heat-release surfaces of annular channels with swirl and transit flow are presented. The experiments were carried out using electric heated annular channels with one and (or) two heat-release surfaces. For the organization of transit flow on a convex heat-release surface, four longitudinal ribs were installed uniformly at its perimeter. Swirl flow was realized using a capillary wound tightly (without gaps) on the ribs. The ratio between swirl and transit flows in the annular gap was varied by applying longitudinal ribs of different height. The experiments were carried out using a closed-type circulatory system. The experimental data were obtained in a wide range of regime parameters. Both water heated to the temperature less than the saturation temperature and water-steam mixture were fed at the inlet of the channels. For the measurement of the temperature of the heat-release surfaces, chromel-copel thermocouples were used. It was shown that the presence of swirl flow on a convex heatrelease surface led to a significant decrease in critical heat flows (CHF) compared to a smooth surface. To increase CHF, it was proposed to use the interaction of swirl flows of the heat carrier. The second swirl flow was transit flow, i.e., swirl flow with the step equal to infinity. It was shown that CHF values for a channel with swirl and transit flow in all the studied range of regime parameters was higher than CHF values for both a smooth annular channel and a channel with swirl. The empirical ratios describing the dependence of CHF on convex and concave heat-release surfaces of annular channels with swirl and transit flow on the geometrical characteristics of channels and the regime parameters were obtained. The experiments were carried out at the pressure p = 3.0-16.0 MPa and the mass velocity ρw = 250-3000 kg/(m2s).

  18. U.S. Space Radioisotope Power Systems and Applications: Past, Present and Future

    Science.gov (United States)

    Cataldo, Robert L.; Bennett, Gary L.

    2011-01-01

    -1906) and R. J. Strut. Almost 100 years ago, in 1913, English physicist H. G. J. Moseley (1887-1915) constructed the first nuclear battery using a vacuum flask and 20 mCi of radium (Corliss and Harvey, 1964, Proceedings of the Royal Society, 1913). After World War II, serious interest in radioisotope power systems in the U.S. was sparked by studies of space satellites such as North American Aviation s 1947 report on nuclear space power and the RAND Corporation s 1949 report on radioisotope power. (Greenfield, 1947, Gendler and Kock, 1949). Radioisotopes were also considered in early studies of nuclear-powered aircraft (Corliss and Harvey, 1964). In 1951, the U.S. Atomic Energy Commission (AEC) signed several contracts to study a 1-kWe space power plant using reactors or radioisotopes. Several of these studies, which were completed in 1952, recommended the use of RPS. (Corliss and Harvey, 1964). In 1954, the RAND Corporation issued the summary report of the Project Feedback military satellite study in which radioisotope power was considered (Lipp and Salter, 1954, RAND). Paralleling these studies, in 1954, K. C. Jordan and J. H. Birden of the AEC s Mound Laboratory conceived and built the first RTG using chromel-constantan thermocouples and a polonium-210 (210Po or Po-210) radioisotope heat source (see Figure 2). While the power produced (1.8 mWe) was low by today s standards, this first RTG showed the feasibility of RPS. A second thermal battery was built with more Po-210, producing 9.4 mWe. Jordan and Birden concluded that the Po-210 thermal battery would have about ten times the energy of ordinary dry cells of the same mass (Jordan and Birden, 1954). The heat source consisted of a 1-cm-diameter sphere of 57 Ci (1.8 Wt) of Po-210 inside a capsule of nickel-coated cold-rolled steel all inside a container of Lucite. The thermocouples were silver-soldered chromel-constantan. The thermal battery produced 1.8 mWe.

  19. Thermoelectric and photovoltaic effects in metal-semiconductor multilayers; Thermoelektrische und Photovoltaische Effekte in Metall-Halbleiter Multilagenstrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Kyarad, A.

    2007-07-01

    In an anisotropic material a heat flux and the resulting thermoelectric field generally are not collinear. Illumination of a thin film can thus lead to transverse thermoelectric voltages: Heat produced at the surface by absorption of light flows perpendicularly to the film plane into a substrate, anisotropy may produce a thermoelectric field component parallel to the film surface leading to a ''transverse'' thermoelectric voltage upon surface heating. Thermoelectric fields transverse to an applied temperature gradient have been observed in tilted metallic multilayer structures. Constantan/chromel/constantan.. multilayers were prepared by sintering stacks of alternating thin foils of these materials. Effective ''in-plane'' and ''out-of-plane'' Seebeck coefficients and heat conductivities of the foil stacks were calculated from data of the isotropic metals. Tilted multilayer structures obtained by cutting stacks obliquely may be used as devices for detection of laser radiation. A comparison is made with respect to responsivity between several multilayer structures and anisotropic crystalline systems. A synthetic material with large thermoelectric anisotropy has been prepared from a metal-semiconductor multilayer structure. By an alloying process, a multilayer stack A-B-A.., where A and B are pure aluminum and n-silicon, is produced with a thermoelectric anisotropy 1.5 mV/K, where and are the absolute Seebeck coefficients along and perpendicular to the layers, respectively. The use of this synthetic material for light sensing applications is demonstrated. Irradiation of an Al-Si multilayer stack with infrared to visible laser radiation generates photovoltaic signals depending on the angle of incidence of the laser beam with respect to the layer planes, with zero signal and a polarity reversal for beam and layers in parallel. Results are explained in terms of photoactive layers connected in series and