SEMI ANALYTIC SOLUTION TO THE CARTESIAN GRAETZ PROBLEM: RESULTS FOR THE ENTRANCE REGION

A solution to the Graetz problem based on a series expansion of the temperature field is reported. The range of Graetz numbers considered has been extended up to a value of 10 9 . The local values of Nu produced by the method are believed to be highly accurate. A correlating expression for Nu, which shows nearly uniform accuracy over the whole Gz range is proposed and compared with previously available correlations