[orange20]

Hi all,

I have been trying to simulate flow through a unit cell of a shell and tube heat exchanger using supercritical CO2 as the working fluid for both the internal (tube) flow and external (shell) flow. I am having trouble obtaining a solution to the problem. I have used the NIST real gas database and I have tried simulating as an incompressible flow as well for simplicity but I cannot seem to converge my solution. I have uploaded a figure of my mesh and the details for my simulation are as follows:

The black arrows in the figure depict external flow inlet and outlet.
The red arrows depict internal flow.

Maximum skewness of the mesh in 0.89.

The mass flow rate throughout the cycle is constant as the heat exchanger is part of a closed loop.

Turbulent flow: Assuming the k-omega SST model

Pressure-based solver

NIST real gas model for supercritical CO2

At tube inlet:

Mass flow rate for each tube (Constant from inlet to outlet) : 0.00184 kg/s

Pressure inlet : 250 bar

Temperature at the inlet : 300 Celsius

At the shell inlet:

Mass flow rate (Constant from inlet to outlet) : 0.1032 kg/s

Pressure inlet : 80 bar

Temperature at the inlet : 800 Celsius

I have been at it for a while now, trying different possibilities but I feel like I am missing something basic. Could any of you be kind enough to help me out with obtaining the solution to this problem?