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Modeling slip flow of gas in the vacuum chamber
Posted Jul 14, 2017, 6:23 a.m. EDT MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Computational Fluid Dynamics (CFD), Microfluidics, Studies & Solvers Version 5.3 0 Replies
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Please, anyone, help me!!!! I'm totally new to Comsol, but my task is to model the flow of air in a chamber of the mass spectrometer connected to the second chamber through the small orifice. There is an inlet of air into the chamber through another small orifice at the opposite wall (i.e., the inlet and the outlet, in terms of boundary conditions). A vacuum pump is attached to one of the chamber walls, and it pumps the air at a constant speed (0.067[m^3/s] ). The chamber walls are made of aluminium. The temperature I guess should be constant. I'm interested in pressure distribution inside of the chamber and the air flux. The pressure in the chamber is 2 mbar (which is below the atmospheric pressure), and hence the flow is in a slip flow regime with 0.01<Kn<0.1. The shape of the chamber is simply a block of dimension 4cm*10cm*19cm.
I use the Slip flow interface for modeling, specifying the boundary conditions that seem appropriate in this case. But the solver ends with the error
Undefined variable.
- Variable: comp1.T
- Geometry: geom1
- Domain: 1
Failed to evaluate variable.
- Variable: comp1.slpf.fluid1.minput_temperature
- Defined as: comp1.T
Hello Anna Shcherbacheva
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