[adi.ptb]

hi,I want to simulate a thermoacoustic engine in fluent,I used design modeler to create my geometry,the geometry consist of a 2d rectangular box and 15 rectangular stacks in it,first i created the box,then i created the stacks using add frozen method then i selected the box and the stacks and used the form new part option,I meshed the geometry successfully and imported the mesh to fluent,the important part is that on the stacks wall i have to assign a linear temperature profile(using a udf) and a heat transfer coefficient for solid fluid heat transfer,when i import the mesh to fluent it creates shadow walls for stack walls to account for conjugate heat transfer,but in the B.C panel i just have temperature,heat flux,and coupled for heat transfer,I can use the temperature option and hook my udf but i dont know how to assign a heat transfer coefficient to the wall,can anyone help me,any help will be appreciated

[ssixr]

Originally Posted by adi.ptb

hi,I want to simulate a thermoacoustic engine in fluent,I used design modeler to create my geometry,the geometry consist of a 2d rectangular box and 15 rectangular stacks in it,first i created the box,then i created the stacks using add frozen method then i selected the box and the stacks and used the form new part option,I meshed the geometry successfully and imported the mesh to fluent,the important part is that on the stacks wall i have to assign a linear temperature profile(using a udf) and a heat transfer coefficient for solid fluid heat transfer,when i import the mesh to fluent it creates shadow walls for stack walls to account for conjugate heat transfer,but in the B.C panel i just have temperature,heat flux,and coupled for heat transfer,I can use the temperature option and hook my udf but i dont know how to assign a heat transfer coefficient to the wall,can anyone help me,any help will be appreciated

Hi adi,
heat transfer coefficient to be applied on fluid surface, not on conjugate wall. what u mean by solid fluid heat transfer...

Sudhir

[adi.ptb]

hi,thanks for reply,the horizontal walls in the stack section are given a constant temperature with a gradient from 700k down to 300k over a distance of 10 mm utilizing a udf,the heat transfer coefficient between the stack walls and the fluid is 50 W/m^2.k,In my first approach that i mentioned in the first post I created the 2d box and 15 stacks in it and formed a new part and defined the stacks as solid zone,but when I went to the B.C panel the stack walls and shadow walls were assigned couple heat transfer,I couldnt use define profile macro,so I switch to the second approach which is creating the 2d box and then subtract the 15 stacks from it,and meshing the inside of the box and outer of the stacks,I think the second approach is more appropriate since I can assign the linear temperature profile with udf,but dont know what to do about the heat transfer between the fluid and stacks wall.what do you think??

[ssixr]

Originally Posted by adi.ptb

hi,thanks for reply,the horizontal walls in the stack section are given a constant temperature with a gradient from 700k down to 300k over a distance of 10 mm utilizing a udf,the heat transfer coefficient between the stack walls and the fluid is 50 W/m^2.k,In my first approach that i mentioned in the first post I created the 2d box and 15 stacks in it and formed a new part and defined the stacks as solid zone,but when I went to the B.C panel the stack walls and shadow walls were assigned couple heat transfer,I couldnt use define profile macro,so I switch to the second approach which is creating the 2d box and then subtract the 15 stacks from it,and meshing the inside of the box and outer of the stacks,I think the second approach is more appropriate since I can assign the linear temperature profile with udf,but dont know what to do about the heat transfer between the fluid and stacks wall.what do you think??

As you have a heat transfer happening between solid and fluid, your first approach is correct. In solid-fluid regions, conjugate heat transfer happens. thats why u see that shadow. whats your problem in first approach?

[ssj]

Dear guys,
I am simulating a thermoacoustic travelling wave heat exchanger using fluent. I would like to know that is it necessary to enable the "acoustics mode" in Fluent in order to extract the thermoacoustic effect?
regrads