HCOEF - Helical Pipe

W.A.

Hi. I am modling flow and H.T. in helical pipe. I am trying to calculate the heat transfer coefficient using the adapco-online Dr. Post help (HCOEF using fluid bulk temperature). Dr. Post uses the SW velocity in calciulating the bulk temperature. It works well in my straight pipe model. However, it gives negative values in case of helical pipe. I tried the ABSO oper as the velocity (I use SU) in helical pipe +ve and -ve in the general Cartisian Cooridenates, but it did not work , HCOEF is -ve, too. Please help. Thanks. W.A.