低蒸汽含量的二相流流动沸腾研究

ON HEAT TRANSFER IN FLOW BOILING WITH LOW VOID RATIO

以R-113为介质,研究了汽泡流和腾涌流流型时的流动沸腾传热。认为液体主体中汽泡的扰动对壁面处的传热有较大影响,当流型发生转变时,其传热机理发生相应的变化。考虑管内汽泡流中汽含率的影响进而导出流动沸腾传热系数表达式,并对氟里昂流动沸腾传热的特点进行了分析。

Studies heat transfer of flow boiling which cotains lower vapour and typifies bubble and churn flow in freon R-113 as the medium. Considers that the bubble fluctuation in main fluid flow importantly affects heat transfer on pipe wail, and the transfer mechanism relatively changes with the flow type. Effect of void ratio in bubble flow is considered, the expression for heat transfer coefficient is derived and the characteritics heat transfer of flow boiling in freon system is analyzed. The relation is:Nu=Nu_f·V_o^(0.8)+3.236[(Re_v/Pr_f)(1-V_o^(0.8)·(Nu_f/Nu))]^(0.7)·D^(0.3)(Re_f·V_o)^(0.56)where the Nu is Nusselt number, V_o void ratio number, Re Reynolds number, Pr Prandtl number; the footing marks f, v note it's in liquid or vapour phase.