Learning Forum

[Timothy Satriya Budiono]

i have problem in simulation about heat transfer. im use ansys fluent. for boundary condition at toip there is heat flux 1000 w/m^2 and bottom use convection for koef heat transfer 10 at temperature 30 C. 

figure 1

for contur temperature from my simulation like that. it different with my reference figure 2

figure 2

simulation figure 2 from my teacher. i still confuse why it was different i already use same step but still different. is it because different version which my teacher use ansys 2020 r1 and i use ansys 2023? or i wrong when set up geometry or mesh?

[Rob]

It's very unlikely to be version related.  What did your teacher do to force the cold spot? What material properties did they use? What value was used for gravity? Is your model fully converged? 

[Timothy Satriya Budiono]

material im use at this journal Nanofluid based photovoltaic thermal systems integrated with phase change materials: Numerical simulation and thermodynamic analysis - ScienceDirect. in thaht journal i use glass cover, eva layer, pv cells, tedlar film, copper absorber plate, pcm layer (as fluid), pipe, and water (as fluid). so top glass is heated by sun, and heat transfer happend from top glass to water. but between pipe there is material can phase change from solid to fluid it is pcm layer. all value use enegry equation and gravity. the odd is my model not converged and temperature is raising so high above 100 C

[Timothy Satriya Budiono]

 

i forget to mention if my model use solidification and melting turn on and around geometry wall is adiabatic. for method im use hybrid and for time is transient. another setting is same from method explain from that journal

 

[Rob]

If you've got temperature dependent density where does the extra volume go? Ie if material expands when it gets warm and the volume is fixed convergence may suffer. 

Talk to your teacher, and in Fluent right-click on the options in the tree & look for "modified settings". What have they set that you haven't?

 

[Timothy Satriya Budiono]

thank you. i will go check that