High Performance Heat Exchanger for Laser Propulsion

Author(s):  
Jordin Kare
1978 ◽  
Author(s):  
C. F. McDonald

With soaring fuel costs and diminishing clean fuel availability, the efficiency of the industrial gas turbine must be improved by utilizing the exhaust waste heat by either incorporating a recuperator or by co-generation, or both. In the future, gas turbines for power generation should be capable of operation on fuels hitherto not exploited in this prime-mover, i.e., coal and nuclear fuel. The recuperative gas turbine can be used for open-cycle, indirect cycle, and closed-cycle applications, the latter now receiving renewed attention because of its adaptability to both fossil (coal) and nuclear (high temperature gas-cooled reactor) heat sources. All of these prime-movers require a viable high temperature heat exchanger for high plant efficiency. In this paper, emphasis is placed on the increasingly important role of the recuperator and the complete spectrum of recuperative gas turbine applications is surveyed, from lightweight propulsion engines, through vehicular and industrial prime-movers, to the large utility size nuclear closed-cycle gas turbine. For each application, the appropriate design criteria, types of recuperator construction (plate-fin or tubular etc.), and heat exchanger material (metal or ceramic) are briefly discussed.


2022 ◽  
Vol 252 ◽  
pp. 115074
Author(s):  
Umamaheswar Puttur ◽  
Masoud Ahmadi ◽  
Behzad Ahmadi ◽  
Sajjad Bigham

2001 ◽  
Author(s):  
Ali Heydari ◽  
Kathy Russell

Abstract A small refrigeration system for cooling of computer system components is evaluated. A thermodynamic model describing the performance of the cycle along with a computer simulation program is developed to evaluate its performance. The refrigeration system makes use of a miniature reciprocating vapor compression compressor. Due to space limitations in some high performance computer servers, a miniature refrigeration system composed of a compressor, capillary tube, a compact condenser, and a cold-plate evaporator heat exchanger are used. Mathematical multi-zone formulation for modeling thermal-hydraulic performance of heat exchanger for the condenser and evaporator are presented. The throttling device is a capillary tube and there is presented a mathematical formulation for predicting refrigerant mass flow rate through the throttling device. A physically based efficiency formulation for simulating the performance of the miniature compressor is used. An efficient iterative numerical scheme with allowance for utilization of various refrigerants is developed to solve the governing system of equations. Using the simulation program, the effects of parameters such as the choice of working refrigerant, evaporating and condensing temperatures on system components and overall efficiency of system are studied. In addition, a RAS (reliability, availability and serviceability) discussion of the proposed CPU-cooling refrigeration solution is presented. The results of analysis show that the new technology not only overcomes many shortcomings of the traditional fan-cooled systems, but also has the capacity of increasing the cooling system’s coefficient of performance.


Author(s):  
Haruaki Kanematsu ◽  
Kazuhiko Murakami

For saving space at an office or a clean room, it is needed to reduce the space of an air conditioner. It is effective to miniaturize a heat exchanger because it occupies the large space in the air conditioner. Three types of a heat exchanger that are an in-line tube and cut fins type, a staggered tube and cut fins type and a staggered tube and uncut fins type were investigated as four inclined angle tests of 0, 45, 60 and 80 degrees in a heat wind tunnel. The coefficients of flow friction and heat transfer rates were obtained from these experiments, and the characteristics of inclined heat exchanger were clarified by effects of tube arrangements, fin types and inclined angles against flow direction. As a numerical approach, two-dimensional steady models were applied on the staggered tube and the in-line tube by using BFC (Boundary-Fitted Coordinate Method); BFC is available to make grids for any install angle of the heat exchanger. The results of the numerical analysis visualized flow patterns and heat transfer in these heat exchangers. In case of 80-degrees angle, the flow makes dead area in a part of the heat exchanger, and it causes reducing performance of the heat exchanger. These results are available for improve a compact high performance heat exchanger.


2013 ◽  
Vol 743-744 ◽  
pp. 88-93 ◽  
Author(s):  
Ya Dong Deng ◽  
Shan Chen ◽  
Xun Liu

The potential for automotive exhaust heat based thermoelectric generator (TEG) has been increased with continuously advances in thermoelectric technology. The thermal performance of the heat exchanger in exhaust-based TEG was analyzed. In terms of interface temperature and thermal uniformity, the thermal characteristics of the heat exchangers with different internal structures, materials and thicknesses were discussed. CFD simulations and infrared experiments on a high-performance production engine with a dynamometer were carried out. It was proved that the plate-shape heat exchanger made of brass with internal baffles and the thickness of 3mm, obtained a relatively optimal thermal performance, and it will help to improve the thermal performance of the TEG.


2006 ◽  
Vol 72 (717) ◽  
pp. 1295-1302
Author(s):  
Naoki SHIKAZONO ◽  
Daisuke OKAWA ◽  
Michio KOBAYASHI ◽  
Nobuhide KASAGI

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