Thermal contact in CEL analysis in Abaqus 6.12

Hello All!

I am doing a CEL simulation involving heat transfer (between Eulerian and Lagrangian domains) in Abaqus. The assembly and meshing can be visualized in the figure attached. The Lagrangian part is a rigid ring (can be seen on the right side in the attached figure). The Eulerian material is modeled as a fluid with EOS and viscosity. The Eulerian domain is partitioned, so that it exactly conforms to the ring's cylindrical profile. The analysis is practically 2 D, therefore the model is only 1 element thick.The mesh is quite fine, so that there is no leakage of the material. A gravity load is applied to the whole model. The ring is fixed to prevent translation, but it rotates with a fixed angular velocity in anticlockwise direction. The interface interactions are, "general explicit -> surface pairs (Eulerian material - ring external surface)", "interaction properties -> tangential=rough, thermal=pressure dependent conductance (value 0 at 0 pascals, and 6000 at 0.001 pascals). The Eulerian material inflows at a specified speed in the Eulerian domain from the top left (horizontal face).

The problem I am facing is that there is insufficient thermal contact at the interface. By visualizing CPress output (for Lagrangian Ring's external contact surface with the Eulerian material), it seems like that the contact pressure is greater then 0 only at very few locations along the interface. Also, it was found that the pressure (in the Eulerian material) drops to negative in many areas (Stress output -> Pressure). Abaqus provides only the possibility of using Pressure dependent thermal conductance behavior at the Eulerian-Lagrangian interface .. therefore I was not able to use the Gap dependent thermal conductance to solve this problem. I tried using Geostatic pressure, but the problem persists. 

The best contact conditions seems to be realized when I prevent any rotation of the ring (based on CPress output for the Ring) ..but even then it was far from perfect. Also, stopping the ring rotation is not the realistic situation.

As the thermal interaction capability for CEL is relatively new in Abaqus,I was not able to find suitable examples online. I will be grateful if someone could advise me on this.

Thanks and Regards,
Paresh