The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform
Mohammed A Quaiyum - One of the best experts on this subject based on the ideXlab platform.
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contact conductance between cladding pressure tube and pressure tube calandria tube of advanced Thermal Reactor atr
Journal of Nuclear Science and Technology, 1994Co-Authors: Hiroyasu Mochizuki, Mohammed A QuaiyumAbstract:In some postulated accidents with coincident loss of emergency coolant injection of the Advanced Thermal Reactor (ATR), the rate of heat transfer to the heavy water moderator that acts as heat sink for the decay heat depends on the contact conductance between cladding and pressure tube, and the same between pressure and calandria tubes. Experiments were performed to assess these contact conductances for clean plates and plates with simulated crud of Fe2O3 powder that is the main ingredient of the crud, and the applicable correlations were also studied. Test specimens were cut from actual pressure tube made of Zr-2.5%Nb and calandria tube made of Zircaloy-2 and flattened to sizes. The artificial waviness of various kinds of height and wave length of 10 mm was machined on the surface of the pressure tube specimen. The ranges of contact pressure, roughness, specimen temperature and gas pressure were from 0.5 to 7 MPa, 4.8 to 100 μm, 400 to 840 K and 0.001 Torr to atmospheric respectively. The experimental re...
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Contact Conductance between Cladding/Pressure Tube and Pressure Tube/Calandria Tube of Advanced Thermal Reactor (ATR)
Journal of Nuclear Science and Technology, 1994Co-Authors: Hiroyasu Mochizuki, Mohammed A QuaiyumAbstract:In some postulated accidents with coincident loss of emergency coolant injection of the Advanced Thermal Reactor (ATR), the rate of heat transfer to the heavy water moderator that acts as heat sink for the decay heat depends on the contact conductance between cladding and pressure tube, and the same between pressure and calandria tubes. Experiments were performed to assess these contact conductances for clean plates and plates with simulated crud of Fe2O3 powder that is the main ingredient of the crud, and the applicable correlations were also studied. Test specimens were cut from actual pressure tube made of Zr-2.5%Nb and calandria tube made of Zircaloy-2 and flattened to sizes. The artificial waviness of various kinds of height and wave length of 10 mm was machined on the surface of the pressure tube specimen. The ranges of contact pressure, roughness, specimen temperature and gas pressure were from 0.5 to 7 MPa, 4.8 to 100 μm, 400 to 840 K and 0.001 Torr to atmospheric respectively. The experimental re...
Hiroyasu Mochizuki - One of the best experts on this subject based on the ideXlab platform.
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contact conductance between cladding pressure tube and pressure tube calandria tube of advanced Thermal Reactor atr
Journal of Nuclear Science and Technology, 1994Co-Authors: Hiroyasu Mochizuki, Mohammed A QuaiyumAbstract:In some postulated accidents with coincident loss of emergency coolant injection of the Advanced Thermal Reactor (ATR), the rate of heat transfer to the heavy water moderator that acts as heat sink for the decay heat depends on the contact conductance between cladding and pressure tube, and the same between pressure and calandria tubes. Experiments were performed to assess these contact conductances for clean plates and plates with simulated crud of Fe2O3 powder that is the main ingredient of the crud, and the applicable correlations were also studied. Test specimens were cut from actual pressure tube made of Zr-2.5%Nb and calandria tube made of Zircaloy-2 and flattened to sizes. The artificial waviness of various kinds of height and wave length of 10 mm was machined on the surface of the pressure tube specimen. The ranges of contact pressure, roughness, specimen temperature and gas pressure were from 0.5 to 7 MPa, 4.8 to 100 μm, 400 to 840 K and 0.001 Torr to atmospheric respectively. The experimental re...
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Contact Conductance between Cladding/Pressure Tube and Pressure Tube/Calandria Tube of Advanced Thermal Reactor (ATR)
Journal of Nuclear Science and Technology, 1994Co-Authors: Hiroyasu Mochizuki, Mohammed A QuaiyumAbstract:In some postulated accidents with coincident loss of emergency coolant injection of the Advanced Thermal Reactor (ATR), the rate of heat transfer to the heavy water moderator that acts as heat sink for the decay heat depends on the contact conductance between cladding and pressure tube, and the same between pressure and calandria tubes. Experiments were performed to assess these contact conductances for clean plates and plates with simulated crud of Fe2O3 powder that is the main ingredient of the crud, and the applicable correlations were also studied. Test specimens were cut from actual pressure tube made of Zr-2.5%Nb and calandria tube made of Zircaloy-2 and flattened to sizes. The artificial waviness of various kinds of height and wave length of 10 mm was machined on the surface of the pressure tube specimen. The ranges of contact pressure, roughness, specimen temperature and gas pressure were from 0.5 to 7 MPa, 4.8 to 100 μm, 400 to 840 K and 0.001 Torr to atmospheric respectively. The experimental re...
Chun-lang Yeh - One of the best experts on this subject based on the ideXlab platform.
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Numerical study of the burner parameters on the Thermal field in a sulfur recovery unit Thermal Reactor
MATEC Web of Conferences, 2018Co-Authors: Chun-lang YehAbstract:A sulfur recovery unit (SRU) Thermal Reactor is the most important equipment in a sulfur plant and is negatively affected by high temperature operations. In this paper, the effect of burner parameters, including the clearance of the acid gas tip and the inlet air swirler angle, on the Thermal field in a SRU Thermal Reactor are investigated numerically, with the aim to reduce the high temperature inside the Thermal Reactor and to ensure an acceptable sulfur recovery. The simulation results show that the burner with a smaller clearance of the acid gas tip produces a lower temperature, a lower exit SO 2 mole fraction and higher exit S 2 and H 2 S mole fractions. Among the clearancs of the acid gas tip investigated, the horizontal clearance of 152.4mm and vertical clearance of 240mm yield the lowest temperature, exit SO 2 mole fraction and highest exit S 2 , H 2 S mole fractions. The burner with a smaller inlet air swirler angle produces a higher temperature, a higher exit SO 2 mole fraction and lower exit S 2 and H 2 S mole fractions. Among the swirler angles investigated, 60° yields the lowest temperature, exit SO 2 mole fraction and highest exit S 2 , H 2 S mole fractions.
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NOx Pollution Analysis for a Sulfur Recovery Unit Thermal Reactor
IOP Conference Series: Materials Science and Engineering, 2017Co-Authors: Chun-lang YehAbstract:A sulfur recovery unit (SRU) Thermal Reactor is the most important equipment in a sulfur plant. It is negatively affected by high temperature operations. In this paper, NOx emissions from the SRU Thermal Reactors are simulated. Both the prototype Thermal Reactor and its modifications, including changing fuel mass fraction, changing inlet air quantity, changing inlet oxygen mole fraction, and changing burner geometry, are analyzed to investigate their influences on NOx emissions. In respect of the fuel mass fraction, the simulation results show that the highest NO emission occurs at a zone 1 fuel mass fraction of 0.375, around which the Reactor maximum temperature and the zone 1 average temperature reach maximum values. Concerning the inlet air quantity, the highest NO emission occurs when the inlet air quantity is 2.4 times the designed inlet air quantity. This is very close to the inlet air quantity at which the maximum average temperature occurs. Regarding the inlet oxygen mole fraction, the NO emission increases as the inlet oxygen mole fraction increases. With regard to the burner geometry, the NO emission increases as the clearance of the burner acid gas tip increases. In addition, the NO emission increases as the swirling strength increases.
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THE EFFECTS OF INLET AIR QUANTITY AND INLET OXYGEN MOLE FRACTION ON THE COMBUSTION AND FLUID FLOW IN A SULFUR RECOVERY UNIT Thermal Reactor
Transactions of the Canadian Society for Mechanical Engineering, 2017Co-Authors: Chun-lang YehAbstract:Owing to the high temperature inside a sulfur recovery unit (SRU) Thermal Reactor, detailed experimental measurements are difficult. In the author’s previous studies, several methods have been assessed to resolve the abnormality of the SRU Thermal Reactor under high temperature operation. This paper presents a new easier and more economical method. The effects of inlet air quantity and inlet O2 mole fraction on the combustion and fluid flow in a SRU Thermal Reactor are investigated numerically. The flow field temperature, S2 recovery, H2S mole fraction, and SO2 emissions are analyzed. This paper provides a guideline for adjusting the inlet air quantity and the inlet O2 mole fraction to reduce the high temperature inside a Thermal Reactor and to ensure an acceptable sulfur recovery.
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The Effect of Fuel Mass Fraction on the Combustion and Fluid Flow in a Sulfur Recovery Unit Thermal Reactor
Applied Sciences, 2016Co-Authors: Chun-lang YehAbstract:Sulfur recovery unit (SRU) Thermal Reactors are negatively affected by high temperature operation. In this paper, the effect of the fuel mass fraction on the combustion and fluid flow in a SRU Thermal Reactor is investigated numerically. Practical operating conditions for a petrochemical corporation in Taiwan are used as the design conditions for the discussion. The simulation results show that the present design condition is a fuel-rich (or air-lean) condition and gives acceptable sulfur recovery, hydrogen sulfide (H2S) destruction, sulfur dioxide (SO2) emissions and Thermal Reactor temperature for an oxygen-normal operation. However, for an oxygen-rich operation, the local maximum temperature exceeds the suggested maximum service temperature, although the average temperature is acceptable. The high temperature region must be inspected very carefully during the annual maintenance period if there are oxygen-rich operations. If the fuel mass fraction to the zone ahead of the choke ring (zone 1) is 0.0625 or 0.125, the average temperature in the zone behind the choke ring (zone 2) is higher than the zone 1 average temperature, which can damage the downstream heat exchanger tubes. If the zone 1 fuel mass fraction is reduced to ensure a lower zone 1 temperature, the temperature in zone 2 and the heat exchanger section must be monitored closely and the zone 2 wall and heat exchanger tubes must be inspected very carefully during the annual maintenance period. To determine a suitable fuel mass fraction for operation, a detailed numerical simulation should be performed first to find the stoichiometric fuel mass fraction which produces the most complete combustion and the highest temperature. This stoichiometric fuel mass fraction should be avoided because the high temperature could damage the zone 1 corner or the choke ring. A higher fuel mass fraction (i.e., fuel-rich or air-lean condition) is more suitable because it can avoid deteriorations of both zone 1 and heat exchanger tubes. Although a lower fuel mass fraction (i.e., fuel-lean or air-rich condition) can avoid deterioration of zone 1, the heat exchanger tubes may be damaged. This paper provides a guideline for adjusting the fuel mass fraction to reduce the high temperature inside the Thermal Reactor and to ensure an acceptable sulfur recovery.
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EFFECTS OF CHOKE RING DIMENSION ON Thermal AND FLUID FLOW IN A SRU Thermal Reactor
Transactions of the Canadian Society for Mechanical Engineering, 2016Co-Authors: Chun-lang YehAbstract:The effects of choke ring dimension on the Thermal and fluid flow in a practical SRU (sulfur recovery unit) Thermal Reactor are investigated numerically. It is found that zone 1 is a higher tempera...
Victor I. Serbin - One of the best experts on this subject based on the ideXlab platform.
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Application of thermionic SNPS with Thermal Reactor for spacecraft orbital transfer mission
1991Co-Authors: Pavel V. Andreev, G. M. Gryaznov, Evgeny E. Zhabotinsky, Anatoly M. Nikonov, Victor I. SerbinAbstract:The region of expedient using of SNPS with in‐core Thermal thermionic Reactor (ITR) is limited by electric power level of about 100 kWe under SNPS lifetime from 3 to 5 years. At the same time the Reactor power may be forced from two to three times during the period of about half a year. The mathematical model of SNPS mass dependence on a degree of forcing is given. The results of calculation of payload masses and transfer times for transfer from low orbit to geostationary orbit for two Thermal Reactors having emission area 1.6 m2 and 2.5 m2 are given for different types of electrojets.
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Using thermionic nuclear power systems with a Thermal Reactor for interorbital space flights
Soviet Atomic Energy, 1991Co-Authors: P. V. Andreev, G. M. Gryaznov, E. E. Zhabotinskii, A. M. Nikonov, Victor I. SerbinAbstract:The use of a thermionic NPS with a Thermal Reactor in space technology to supply power to the RMPS offers broad possibilities for interorbital delivery of payloads while using comparatively cheap launch rockets to place spacecraft in a fixed orbit. The flight time from a fixed to a geostationary orbit ranges from several months to half a year, and the mass of the payload in a geostationary orbit for optimal RMPS parameters may reach 7–8 tons (not counting the mass of the NPS). It should be noted that after the flight is completed, the NPS can serve as a source of electrical power for spacecraft in geostationary orbit.
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The conceptual design and main characteristics of long life time thermionic SNPS with Thermal Reactor
AIP Conference Proceedings, 1991Co-Authors: Pavel V. Andreev, G. M. Gryaznov, Evgeny E. Zhabotinsky, Anatoly M. Nikonov, Gennady A. Zaritsky, Victor I. SerbinAbstract:The electric power of thermionic SNPS with Thermal Reactor is limited to about 100 kWe under lifetime of 5 or more years. The possible conceptual designs of this thermionic SNPS and its basic units are described. The mass optimization had carried out for different SNPS conceptual designs and permissible levels of ionizing radiation. The optimal lengths from the core center to the user interface module plane had defined. The dependence of specific mass of this optimized SNPS on the electric power in the range from 15 to 60 kWe under permissible radiation dozes from 105 to 106 rad are given.
Alan W. Weimer - One of the best experts on this subject based on the ideXlab platform.
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use of image based direct normal irradiance forecasts in the model predictive control of a solar Thermal Reactor
Journal of Solar Energy Engineering-transactions of The Asme, 2014Co-Authors: Elizabeth Saade, David E. Clough, Alan W. WeimerAbstract:A model predictive control (MPC) system for a solar-Thermal Reactor was developed and applied to the solar-Thermal steam-gasification of carbon. The controller aims at rejecting the disturbances in solar irradiance, caused by the presence of clouds. Changes in solar irradiance are anticipated using direct normal irradiance (DNI) forecasts generated using images acquired through a Total Sky Imager (TSI). The DNI predictor provides an estimation of the disturbances for the control algorithm, for a time horizon of 1 min. The proposed predictor utilizes information obtained through the analysis of sky images, in combination with current atmospheric measurements, to produce the DNI forecast. The predictions of the disturbances are used, in combination with a dynamic model of the process, to determine the required control moves at every time step. The performance of the proposed DNI predictor-controller scheme was compared to the performance of an equivalent MPC that does not use DNI forecasts in the calculation of the control signals. In addition, the performance of a controller fed with perfect DNI predictions was also evaluated.
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Model predictive control of a solar-Thermal Reactor
Solar Energy, 2014Co-Authors: Elizabeth Saade, David E. Clough, Alan W. WeimerAbstract:Abstract This paper presents the application of a Model Predictive Control (MPC) system to a solar-Thermal Reactor for carbon-steam gasification. The controller aimed at rejecting the disturbances in solar irradiation, caused by the presence of clouds, through the manipulation of the flow rates into the Reactor. Simulations of a first-principles dynamic model were used to fit a linear, time-invariant model, to be used directly in the MPC algorithm. The MPC was tuned through simulations, until robust control was achieved. The proposed control system was compared to a fine-tuned multi-loop feedback control strategy. Simulations of the controlled Reactor system showed that the linear MPC was capable of minimizing the effect of the disturbances within the entire operating region, outperforming a more conventional multi-loop feedback strategy. The results obtained suggest that the proposed controller is suitable for a real-world implementation.
