过载环境下1.002mm管内流动沸腾传热的实验

通过地面离心转台模拟过载,对R134a在内径为1.002 mm管内的沸腾流动传热进行了实验研究。结果表明:管内流动沸腾传热特性随着重力的变化而变化；在重力为3.16g(g=9.8 m/s2)时,过载下的传热系数比常重力下的大；随着过载的增加,大多数情况下传热系数先增大后减小,转折点在1.1g~1.4g；在3.16g时,部分传热系数开始出现低于1g时的情况；干度对传热系数的影响特性因重力不同而不同。研究了常重力下流动沸腾预测模型对过载环境的适应性,鉴别出了对过载数据预测较好的公式。 

Experiment on flow boiling heat transfer in 1.002 mm tube under hypergravity

An experiment investigation of R134a flow boiling heat transfer in a 1.002 inner diameter mini-tube under hypergravity was carried out, with the hypergravity environment being achieved using a centrifugal acceleration machine. Results showed that a remarkable difference existed in flow boiling heat transfer between hypergravity and normal gravity. The heat transfer under hypergravity was stronger than that under normal gravity in the gravity of 3.16g (g=9.8 m/s2). With the increase of gravity, heat transfer coefficients increased at first and then decreased. The transition took place around 1.1g-1.4g. At 3.16g, some heat transfer coefficients became smaller than those at normal gravity. The effects of vapor quality on the heat transfer varied with gravity. The applicability of correlations for flow boiling heat transfer under normal gravity to hypergravity was also evaluated, and those having good prediction performances for hypergravity were identified.