## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### Temperature unchanged with convection coefficient

• Kiran Kolluru
Subscriber

Hi all, I am running an analysis to simulate a thermal pulse inside a cylinder. Pulse duration is 5 milli seconds (ms) with maximum temperature of 2700 degC and reduces to 1500 degC by the end of pulse. I am interested in knowing what is the maximum temperature inside cylinder after 90 ms. There is a cooling jacket around the cylinder with water circulating at 25 degC. I am trying several heat transfer coefficients (applied on cylinder outside surface) to eventually determine the jacket dimensions. But for any heat transfer coefficient (10 W/m2 C to 1E7 W/m2 C), the inside surface temperature of cylinder remains constant at 310 deg C at the end of 90 ms. Can someone suggest why the cylinder inside temperature is not changing with changing heat transfer coefficient? Is the time of 90 ms too short to see the effect of heat transfer coefficient? Of course, when the time duration is left up to 1 second, then the temperature is falling down to 90 degC.

I am attaching images of temperature distribution result after 90ms and the temperature ouput result.

Thank you.

• Kiran Kolluru
Subscriber

The fact that temperature remains unchanged seems ok from concept of heat transfer coefficient - amount of thermal energy (Watt) that will be removed per m2 area for a given temperature difference (degC). So for a given time duration, only certain Joules of energy can be removed. But while designing a cooling jacket, how the parameters such as volume of water in jacket, velocity of water, etc. can be considered in analysis?