Joule Heating and Laminar Flow in microfluidics

I'm trying to find the temperature distribution in a microfluidic channel. The heat is generated by two electrode in a microfluidic channel. When I create the model without laminar flow everything looks fine. I can get the temperature increase in the channel by the joule heating.

However, as soon as I add laminar flow, all of the velocity profiles look fine, but there is no heat generated. I noticed the electrical field within the channel is no longer available (not applicable). Does this mean that I cannot combine laminar flow with joule heating for fluids? While using the laminar flow model I cannot have electrical current through any of my fluids? Is there anyone has idea to solve this problem?

Thanks.