NUMERICAL ANALYSIS TO DESIGN HIGH TEMPERATURE HEAT EXCHANGER OF BETA TYPE STIRLING ENGINE IN 3-D COMBUSTION FIELD

This research proposed a novel shape design by integrating the geometry that showed the best performance including fin length, pitch and angle on the high temperature heat exchanger of Stirling engine designed for the prime mover of 1kW cogeneration system for home. First, the numerical simulation was conducted on the new design and existing shape, and the performance improvement according to the shape optimization was checked. Next, the validity of its performance was verified by additionally considering the heat loss from the recuperation and low-temperature heat exchanger. As a result, when the high temperature heat exchanger is optimized, a great amount of heat quantity is absorbed from the fuel gas from the upstream part where negative heat flux occurred in the cylinder head part. This was judged to be because of the fixed temperature of the high-temperature part in the thermodynamic cycle. Thus, when researching the shape of the high-temperature heat exchanger, an optimized geometry can be obtained when combining cycle interpretation of system rather than interpreting independently.

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

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2012.06.011 ◽

2013 ◽

Vol 50 (1) ◽

pp. 886-895 ◽

Cited By ~ 13

Author(s):

Min Zeng ◽

Ting Ma ◽

Bengt Sundén ◽

Mohamed B. Trabia ◽

Qiuwang Wang

Keyword(s):

High Temperature ◽

Heat Exchanger ◽

Finned Tubes ◽

Temperature Heat

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

Volume 3: Design and Manufacturing ◽

10.1115/imece2007-42199 ◽

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.

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

Thermal Science ◽

10.2298/tsci0904041m ◽

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.

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