[popezmark]

Hi everyone!
I'm an OpenFoam rookie and I'm tryng to use it for my thesis regarding the so called "Wave Rotor". I think you know what I'm talking about better than me, nevertheless I'll try to explain. The device is a cylindrical rotor with a certain number of straight channels. The rotor in enclosed in a case with ports that permit the passage of fluid through the channels. The rotor rotation ( ) determines the opening and closure of the inlet and outlet of the channels. The Wave Rotor can be used in a turboengine essentialy in two ways:
1) 4 port Wave Rotor ( NASA studies this case for 20 years) : the Wave Rotor is connected with the compressor (inlet), the combustor (inlet for hot gas and outlet for compressed air) and the turbine (outlet low pressure gas). The rotor work as a pressure exchanger, fresh air from the compressor enters the WR and is compressed by the hot exhaust gas coming from the combustor. The hot exhaust gas is then expanded (and cooled) and exits the WR to the turbine.
2) 2 port Wave Rotor Combustor : in this case the WR replaces entirely the combustor; the fresh air comes from the inlet (compressor) and in the channels, when inlet and outlet are closed, we can perform a costant volume combustion. The exhaust gas exit from the outlet and reach the turbine.
I hope I've explained clearly with my terrible English!
I want to perform a series of simulations of this two cases, starting with the first. I want to make a first very simple 2d approximation of a single straight channel of the rotor. At the instant 0, in the channel there is fresh low pressure air (zero velocity), the outlet is CLOSED, and from the inlet flows inside hot high pressure gas. I expect the formation af a shock wave moving from the inlet to the outlet and reflecting back, and of course there will be a contact surface between the two fluids at different temperature. An istant BEFORE the shock wave is reflected back, the outlet is opened, and the simulation go on with other fases...
So, I need to simulate a highly transient, compressible and probably turbolent flow, and I need to change the boundary conditions at inlet and outlet at specific istants (sigh!)
- Can you please suggest me what solver is more suitable for this application? I think of rhoPisoFoam with LES for turbolence, similar to the tutorial PitzDaily, but I note that in the new OpenFoam 2.0 this solver is no more... maybe rhoPimpleFoam?? And how can I describe correctly the conditions (pressure, temperature and velocity) at the boundary inlet and outlet?
- What are alphSgs, B, k, muSgs, muTilda? Can you suggest me some good information source to understand how rhoPiso (or rhoPimple) works? I coldn't find any...
- How can I perform the changing in course of the boundary conditions?
Thanks for your attention, I can't wait to read your answers!
Marco