【摘要】 至今,层流等热流加热圆管进口段内同时求解温度与速度分布,一般假定速度边界层已充分发展和粘度μ为常数,而且大都采用积分方法。本文采用数值计算的方法,分别对μ=常数及μ=f(T)两种情况进行了计算,得到了各截面的、沿对称轴线上的速度和温度分布,以及速度边界层充分发展所需长度。计算结果与实验数据的符合程度是相当好的,计算表明μ随温度变化对结果影响显著。更多还原

【Abstract】 So far in order to predict velocity and temperature profiles in an entrance region of a circular tube with uniform flux, the integral method is usually utilized and, in general, the assumptions of fully developed flow and μ= const, are made. In this paper the method of numerical calculation is used. The calculation is carried out for μ= const, and μ=f(T) respectively. The velocity and temperature distributions on various cross sections and along the axis are obtained and so is the length needed for fully developed flow. The agreement of predicted results with experimental data is quite good. It’s found that the vaviation of μ with temperature has great influence on results.更多还原