An issue with temperature change in unsteady prob
 

Hi All I've an oil pipe with a 90 degree branching in between the pipe. The sensor assembly locates in the branching zone. Surrounding the pipe branching, there is air flow to cool the branching region. The initial temperature of the solid components inside the sensor assembly will be 360 K whereas the air temperature is 296 K. The infusing temperature of the oil is 423 K and the aim of the simulation is to find the time when the components of the sensor assembly will reach the temperature of the oil.

There is a temperature rise on each component only for the I time step. When the solution converges for the I time step and from the II time step the temperature is getting stabilized. I don't see further increase in the temperature of the components in the later time steps. According to experimental data the components reach the maximum temperature at 160 secs and the time step what I taken is only 2 secs and 85 time steps.

Also to my problem following is how I've initialized the case.

Initialize all zones with 0 gauge pressure and 296 K Patch oil domain with 423 K Patch solid components with 360 K Monitoring volume average temperature for solids inside sensor assembly

Requesting help.

regards Ashok

Re: An issue with temperature change in unsteady p
 

Do you have a developed flow in the pipe and outside before analysing the temperatures? how do you impose the flows in the pipe and outside?

how are the initial conditions of your experiments? is the pipe full of flowing oil?