ソーラーガスタービン用マイクロチャンネル熱交換器の伝熱流動特性

概要

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Highly compact heat exchangers are desired for regenerative gas turbine cycle with super critical carbon dioxide as a working fluid. A set of empirical correlations of local heat transfer coefficient and pressure loss coefficient are newly derived based on experiments using micro channel heat exchanger (MCHE) with supercritical carbon dioxide as a working fluid. They are Nu = C_1 Re^<0.8>Pr^<0.6>, C_1 = 0.0473, f = C_2Re^<0.25>, C_2 = 2.29. The same correlation of Nusselt number is found applicable to both fluids and its value is almost two times larger than Dittus Boelter correlation. It was also shown that the above form is applicable to a wide range of geometry with the values of constants C_1 and C_2 changed. For example, the correlations with C_1 = 0.010 and C_2 = 0.155 are applicable to an existing tubular heat exchanger. Accuracy of both correlations is confirmed within 5% errors for MCHE with S-shaped fins in the range of pressures 9 〜 12.5MPa and temperatures 280 〜 390K. Based on the correlations, design method of heat exchanger is also developed.
公益社団法人日本ガスタービン学会の論文
2007-03-30