I'm working on a test bench for thermal exhaust blankets. We would like to test different jacket insulation for an exhaust pipe temperature of 1250 F and a mass flow rate 300 g/s. We usually control the skin temperature of the pipe from the torch flame we set up in the beginning of the pipe without paying attention to the mass flow rate of the exhaust. How can I set up a mass flow rate measurement or control of such high temperature application? Our test bench consist only of a propane tank with a torch that heat up with exhaust the pipe to the temperature we want.