Numerical modeling of compact high temperature heat exchanger and chemical decomposer for hydrogen production

2008 ◽  
Vol 44 (11) ◽  
pp. 1379-1389 ◽  
Author(s):  
Valery Ponyavin ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
Merrill Wilson
Keyword(s):  
Numerical Modeling ◽  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Temperature Heat

Design of a Compact Ceramic High-Temperature Heat Exchanger and Chemical Decomposer for Hydrogen Production

2012 ◽  
Vol 33 (10) ◽  
pp. 853-870 ◽  
Author(s):  
Valery Ponyavin ◽  
Yitung Chen ◽  
Taha Mohamed ◽  
Mohamed Trabia ◽  
Anthony E. Hechanova ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Temperature Heat

Fluid/Thermal Analysis of High Temperature Heat Exchanger and Chemical Decomposer for Hydrogen Production

2007 ◽  
Author(s):  
Valery Ponyavin ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
Merrill Wilson
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Three Dimensional ◽  
Flow And Heat Transfer ◽  
Temperature Heat ◽  
Improved Design ◽  
Sulfuric Acid Decomposition

This paper presents fluid flow and heat transfer study of a high temperature heat exchanger and chemical decomposer. The decomposer will be used as a part of the plant for hydrogen production. The decomposer is manufactured using fused ceramic layers that allow creation of channels with dimensions below one millimeter. The main purpose for this study is to increase thermal performance of the decomposer which can help to intensify sulfuric acid decomposition rate. Effects of using various channel geometries of the decomposer on the pressure drop are studied as well. A three-dimensional computational model is developed for the investigation of fluid flow and heat transfer in the decomposer. Several different geometries of the decomposer channels such as straight channels, ribbed ground channels, hexagonal channels, and diamond-shaped channels are examined. Based on results of the calculation, the recommendations for the improved design of the decomposer are obtained.

Development of an Advanced High Temperature Heat Exchanger Design for Hydrogen Production

2004 ◽  
Author(s):  
Sundaresan Subramanian ◽  
Roald Akberove ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
Clayton Ray De Losier
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Numerical Simulations ◽  
Transfer Enhancement ◽  
Heat Exchanger Design ◽  
Temperature Heat ◽  
Fin Thickness ◽  
Offset Strip Fin

This paper deals with the development of an advanced high temperature heat exchanger design for hydrogen production by the sulfur iodine thermochemical cycle from advanced nuclear reactor concepts. The offset strip-fin hybrid plate type compact heat exchanger concept is chosen, and the material of manufacture is the liquid silicon impregnated carbon composite. The offset strip-fin is chosen as a method of heat transfer enhancement due to the boundary layer restart mechanism between the fins that has a direct effect on enhancing heat transfer. The effect of the fin thickness, pitch in flow direction, and the aspect ratio of the offset fins on the flow field and heat transfer are studied in 2-D using Computational Fluid Dynamics (CFD) techniques, and the results are then compared with the analytical calculation results. The preprocessor GAMBIT is used to create a computational mesh, and the CFD software package FLUENT, that is based on the finite volume method is used to produce numerical results. Proper dimensions of the strip fins need to be chosen in order to have an optimized heat transfer enhancement coupled with a reduced pressure drop. The study is conducted with helium gas as the working fluid with varied of Reynolds number values. The flow and heat transfer is considered to become periodically fully developed after a certain entrance length hence numerical simulations were performed using periodic boundary conditions. Two-dimensional numerical simulations were also performed for the whole length of the heat exchanger which has 37 such periodic modules. Comparison study was performed between the cases of fins with rectangular and curved geometry. Attempt has also been made in order to validate the coefficient of fin thickness (Cfin) value using CFD techniques, which has been used in the existing empirical correlations to suit this type of heat exchanger geometry. The model developed in this paper is used to investigate the heat exchanger design parameters in order to find an optimal design.

Effect of lateral fin profiles on stress performance of internally finned tubes in a high temperature heat exchanger

2013 ◽  
Vol 50 (1) ◽  
pp. 886-895 ◽  
Author(s):  
Min Zeng ◽  
Ting Ma ◽  
Bengt Sundén ◽  
Mohamed B. Trabia ◽  
Qiuwang Wang
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Finned Tubes ◽  
Temperature Heat

Transient Analysis of a Ceramic High Temperature Heat Exchanger and Chemical Decomposer

2007 ◽  
Author(s):  
Valery Ponyavin ◽  
Taha Mohamed ◽  
Mohamed Trabia ◽  
Yitung Chen ◽  
Anthony E. Hechanova
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Finite Element Software ◽  
Micro Channels ◽  
Temperature Heat

Ceramics are suitable for use in high temperature applications as well as corrosive environment. These characteristics were the reason behind selection silicone carbide for a high temperature heat exchanger and chemical decomposer, which is a part of the Sulphur-Iodine (SI) thermo-chemical cycle. The heat exchanger is expected to operate in the range of 950°C. The proposed design is manufactured using fused ceramic layers that allow creation of micro-channels with dimensions below one millimeter. A proper design of the heat exchanges requires considering possibilities of failure due to stresses under both steady state and transient conditions. Temperature gradients within the heat exchanger ceramic components induce thermal stresses that dominate other stresses. A three-dimensional computational model is developed to investigate the fluid flow, heat transfer and stresses in the decomposer. Temperature distribution in the solid is imported to finite element software and used with pressure loads for stress analysis. The stress results are used to calculate probability of failure based on Weibull failure criteria. Earlier analysis showed that stress results at steady state operating conditions are satisfactory. The focus of this paper is to consider stresses that are induced during transient scenarios. In particular, the cases of startup and shutdown of the heat exchanger are considered. The paper presents an evaluation of the stresses in these two cases.

scholarly journals Thermodynamic modelling and efficiency analysis of a class of real indirectly fired gas turbine cycles

2009 ◽  
Vol 13 (4) ◽  
pp. 41-48
Author(s):  
Zheshu Ma ◽  
Zhenhuan Zhu
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Waste Heat ◽  
Operational Parameters ◽  
Forecast Performance ◽  
Micro Gas Turbine ◽  
Temperature Heat

Indirectly or externally-fired gas-turbines (IFGT or EFGT) are novel technology under development for small and medium scale combined power and heat supplies in combination with micro gas turbine technologies mainly for the utilization of the waste heat from the turbine in a recuperative process and the possibility of burning biomass or 'dirty' fuel by employing a high temperature heat exchanger to avoid the combustion gases passing through the turbine. In this paper, by assuming that all fluid friction losses in the compressor and turbine are quantified by a corresponding isentropic efficiency and all global irreversibilities in the high temperature heat exchanger are taken into account by an effective efficiency, a one dimensional model including power output and cycle efficiency formulation is derived for a class of real IFGT cycles. To illustrate and analyze the effect of operational parameters on IFGT efficiency, detailed numerical analysis and figures are produced. The results summarized by figures show that IFGT cycles are most efficient under low compression ratio ranges (3.0-6.0) and fit for low power output circumstances integrating with micro gas turbine technology. The model derived can be used to analyze and forecast performance of real IFGT configurations.

Experimental Studies on Thermal Performance of a Pebble Bed High-Temperature Heat Exchanger

1985 ◽  
Vol 107 (3) ◽  
pp. 722-727 ◽  
Author(s):  
K. Yoshikawa ◽  
H. Kajiyama ◽  
T. Okamura ◽  
S. Kabashima ◽  
H. Yamasaki ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Experimental Studies ◽  
Pebble Bed ◽  
Temperature Heat

scholarly journals Thermal Performance of a 2000.DEG.C. Class Cored-Brick Bed High-Temperature Heat Exchanger.

1996 ◽  
Vol 62 (604) ◽  
pp. 4248-4253
Author(s):  
Satoshi UEOKA ◽  
Kunio YOSHIKAWA ◽  
Suwat RAVEEVONGANOTHAI ◽  
Susumu SHIODA ◽  
Saburou IKEDA ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Temperature Heat

Fluidized-Bed Heat Transfer Modeling for the Development of Particle/Supercritical-CO2 Heat Exchanger

2017 ◽  
Author(s):  
Zhiwen Ma ◽  
Janna Martinek
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Solid Particles ◽  
Heat Transfer Modeling ◽  
Power Cycle ◽  
Heat Exchanger Design ◽  
Temperature Heat ◽  
The Cost

Concentrating solar power (CSP) technology is moving toward high-temperature and high-performance design. One technology approach is to explore high-temperature heat-transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (s-CO2) Brayton power cycle. The s-CO2 Brayton power system has great potential to enable the future CSP system to achieve high solar-to-electricity conversion efficiency and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat-transfer medium that is inexpensive and stable at high temperatures above 1,000°C. The particle/heat exchanger provides a connection between the particles and s-CO2 fluid in the emerging s-CO2 power cycles in order to meet CSP power-cycle performance targets of 50% thermal-to-electric efficiency, and dry cooling at an ambient temperature of 40°C. The development goals for a particle/s-CO2 heat exchanger are to heat s-CO2 to ≥720°C and to use direct thermal storage with low-cost, stable solid particles. This paper presents heat-transfer modeling to inform the particle/s-CO2 heat-exchanger design and assess design tradeoffs. The heat-transfer process was modeled based on a particle/s-CO2 counterflow configuration. Empirical heat-transfer correlations for the fluidized bed and s-CO2 were used in calculating the heat-transfer area and optimizing the tube layout. A 2-D computational fluid-dynamics simulation was applied for particle distribution and fluidization characterization. The operating conditions were studied from the heat-transfer analysis, and cost was estimated from the sizing of the heat exchanger. The paper shows the path in achieving the cost and performance objectives for a heat-exchanger design.

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