Hello everyone,

I have recently done simulations in Abaqus 2022 Explicit about convective heat transfer between a liquid and a metal plate. The method which I chose in the Step for this simulation is Dynamic, Temperature-displacement, Explicit. The heat transfer occurs on one surface of the plate, which is penetrated by a liquid jet. Heat transfer shall occur in the contact area between liquid and solid. Thus I implemented via a python function which detects the contact area between liquid and solid through the C_PRESS data on the nodes of the contact surface of the metal plate. And the resulted area was taken as analytical field (mapped field whose field value at each node is set as 1) which is used in my film conditions.

For the initial conditions I set the contact time of the water as 2.5 seconds, the film coefficent was set at 10000 and I calculated the Reynolds-number in my case which is about 1.124*10^9.

In order to place the film coefficient in the simulation, I’ve used two different approaches to simulate this case: surface film coefficient and concentrated film coefficient.

First I did a simulation with the surface film condition and chose the surface-geometry of the convection area and compared the results to a simulation in which I made use of the concentrated film condition for which I chose all nodes on the plate surface as node-set which were in contact with the liquid (just like what shows in picture1). Both cases were simulated with the same model and same initial conditions. What made me confused is that the results of this two kind of film conditions differs a lot from one another: The temperature drops in concentrated film condition a lot more than in surface film condition (about 10 times in the picture2). Although the offical website says clearly, that the surface film conditions define convection from model surfaces, and concentrated film conditions define convection from nodes or vertices. I still don´t really get the difference. Could anyone please tell me the physical difference between these two kind of film conditions? I would be very thankful if you also could give an example of a case of simulation which fits concentrated film condition. Thank you very much!