Conjugate Heat Transfer Simulation

OBJECTIVE: Conjugate heat transfer throuhg cylinder. Performing grid dependency test and observing the effect of change in super-cyling interval.

Spercycling: In fliuid H.T takes place faster than the solid region, therfore to over come this fluid solver is made to freeze periodicaaly while the heat transfer in solid region is allowed to reach the stedy state. This concept of solving the disparity in the time scales is caleed siper-cyling.

• Flow through a pipe is simulated with inlet Reynolds number 7000 and the calculated inlet velocity is 7 m/s
• Turbulance model used - K-Epsilon, super-cyling option is enabled
• For Grid dependency test 0.002, 0.003, 0.004m base grid is used.
• Chane in temperature in the solid region at perticular point is plotted wrt time.

Grid dependency test:

For base grid of - 0.004m

Base Grid

Temperature Magnitude

Velocity Magnitude:

Mean Temperature:

• For base of -0.003

Base Grid

Temp Magnitude:

Velocity Magnitude:

Mean Temp:

For base Grid - 0.002m

Base Grid

Temp Magnitude

Velocity Magnitude

Mean Temp

Comparision of the results with different base grid

Even 0.002m base grid is not grid independant. There is a noticable change in the result for the chosen three base grids. Much finer grid is of 0.001m will be grid independant as it consits of roughly 343610 cells. Simulation with 0.001m base grid is not carried out as it is too much for the my PC configuration.

Efect of super-cyling stage interval

Super-cyling stage interval 0.03 - Simulation time 366.243699 s

Super-cyling stage interval 0.02 - Simulation time 353.165411 s

Super-cyling stage interval 0.01 - Simulation time 311.079809 s

OBSERVATIONS:

• As the super -cyling stage interval decreases, simulation yime deceases
• Steady state is obtained quicker in 0.01 when copared with 0.02 and 0.03 super-cyling stage interval i,e slope of the temperature curve is higher

Animation video can be seen below: