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RF heating of fluid

Posted Jun 18, 2011, 7:10 p.m. EDT RF & Microwave Engineering Version 4.1 1 Reply

Pranjali Muley
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Hi all,

I am working on heating of fluid in a microwave. I have a waveguide and a pipe filled with the lossy fluid. The microwave frequency used in 915MHz and a wave excitation of 4000W. I have defined the material properties (air in the waveguide and fluid in the pipe) The dielectric permittivity of the fluid id temperature dependent. so is conductivity. electric wave equation for the waveguide. microwave heating active in pipe domain.
The boundary conditions defined are as follows
RF heating : Port - rectangular with wave excitation 4000W
Continuity - for internal boundaries
Rest are perfect electric conductors

Heat: Transfer : Active only in pipe domain
Scattering boundary condition at the inlet and outlet of pipe
inlet temperature - 25 C
outflow
Rest are perfect thermal insulators
Mesh : satisfies the Nyquists criterion
Solved in frequency transient study for 60sec and time step of 10sec.

However, I am getting unexpected results. The temperature rises upto 80C (which is fine) but the rise is not uniform with max. temperature near inlet and outlet. Am I missing a boundary condition? Also is the continuity boundary condition by default for the internal boundaries?

Thank you,
Pranjali
1 Reply Last Post Oct 10, 2011, 1:04 p.m. EDT
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Hello Pranjali Muley

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Muhammad Mohsin Rehman
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Posted: 1 decade ago Oct 10, 2011, 1:04 p.m. EDT
Hi Pranjali,

I am also working on a similar model but could not get the temperature distribution. I am getting the same temperature as was defined in Initial Conditions.
Can you please share your model with me so as I may understand where I am making mistake?

Any help will be highly appreciated.

Thanks.
Hi Pranjali, I am also working on a similar model but could not get the temperature distribution. I am getting the same temperature as was defined in Initial Conditions. Can you please share your model with me so as I may understand where I am making mistake? Any help will be highly appreciated. Thanks.

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