Heat transfer studies are an integral part of Flow Simulation. Can you provide more details about what you'd like to Simulate? Maybe a screen shot of your system?
Flow will model hot water flow in a heat exchanger or pipe or tank. It will also model the flow of two liquids such as water and propylene glycol in solution. Water is included in the database for a wide variation of temperatures. You may have to add the characteristics of any other fluid that may be in solution with the water. But it will not model two phase flow (liquid + gas).
However, modeling the heat exchanger is about 99% of the work.