【摘要】 本文在热管平板集热器传热分析的基础上,对铝-丙酮和铝-氨重力热管(无芯网或槽道的光管)在太阳能平板集热器的热流密度下的传热特性进行了实验研究,发现热管工质的最佳充装量约为25％左右。实验表明,在低热流密度条件下,热管蒸发段的换热系数较低,集热器系统的设计又不允许热管有过长的冷凝段,使热管对载热质的总传热系数略低于常规平板集热器流道中的对流换热系数。故热管集热器的效率因子将略低于同类型常规集热器。实验结果还指出,热管集热器的热容小,起动快,它的全日效率略高于常规集热器。重力热管集热器系统能防冻、防腐,其热性能优于双回路系统,有进一步研制的价值。更多还原

【Abstract】 Based upon the heat transfer analysis on the performance of the heat pipe flat plate collector,some experimental study on the heat transfer characteristics of a closed type thermosyphon under the heat flux condition of flat plate collectors were carried out.Twosorts of the gravity assisted wickless heat pipe (GAWHP)----aluminium-acetone and aluminium-ammonia---- in various size were tested.Their optimum quantity of fluidcharge was found to be about 25% (inside volume).Under the optimum filling and the length ratio of the evaporation zone to the condensation,Le/Lc,equal to 2.75,the over-all heat transfer coefficient of the heat pipes,KHP,were measured.An outdoor performance testing on a GAWHP collector and a conventional one which has the same structure were carried out simultaneously.The result shows that the efficiency factor of the GAWHP collector is about 6% lower than that of the conventional one.However,owing to its low heat capacity and thermodiode effect,the whole day performance of the GAWHP collector system is somewhat higher than that of the conventional one.The research comes to a conclusion that,comparing to the double-loop flat plate collector system,the GAWHP collector system appears more cost-effective.更多还原