瞬态热容法在平板冲击换热特性研究中的适用性

分别采用试验和数值计算的方法,对瞬态热容法在自由射流冲击平板表面换热特性的适用性进行了研究。试验研究和数值研究均表明,Bi和Fo均对瞬态热容法Nu′测量精度有较大影响。在所选取的工况范围内,随Fo和Bi增大,Nu′和经典试验值7]的偏差均不断增大。并且,在距离冲击点1倍孔径处,Bi=0.001,Fo=10时,用瞬态热容法得到的冲击表面Nu′分布的相对误差约为2%。Bi在0.0005~0.005之间,Fo在10~20之间,相对误差小于6%。

Applicability of Transient Thermal Capacity in Study of Impinge Flat Heat Transfer Characteristics

The applicability of transient thermal capacity in the study of impinge flat heat transfer characteristics was investigated respectively by the experimental and numerical method.The results show that Bi and Fo both have a great effect on the Nu＇ measurement accuracy of the transient thermal capacity.In the selected working range,if the Bi or Fo increases,the deviation between Nu＇ measurement and typical values increases.At distance which was one diameter to impinge point,if choosing Bi（at r/d=1） close to 0.001,Fo close to 10,the relative deviation of the impinge surface Nu＇ closes to 2% using the transient heathermal capacity,and it can be kept under 6% if choosing Bi（at r/d=1）between 0.0005 and 0.005,and Fo between 10 and 20.