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ME July 2, 2007 09:18

radial turbine flow analysis
Hi, everybody, I am simulating radial inflow gas turbine. For that i m finding these queries. pls let me know if anybody knows (1) Which type of BCS should be used? Inlet total pressure is 2.73 bar and total temp is 923 K. which type of inlet turbulence shu be specified? (2) which type of turbulence model should be used? Should I use spalart allmaras, ke (low RE) or Reynolds stress model? I was thinking to apply ke initially and once it is getting converged, then switch over to RSM. Pls also let me know, that is there any low Re model in CFX?(3) how much should I extend my domain at inlet and outlet? Is that any thumb rule? (4) Presently i am thinking to run analysis at 10 percent of speed and then slowly increasing it once it is converged? (blade speed is 60,000 rpm). Is it ok? is tht ant thumb rule? (5) If I want to take secondary flow into account, then what shud me my mesh requirement? (6) Shud I do transient or steady? Thanks a lot.

Ahmed emad July 6, 2007 09:34

Re: radial turbine flow analysis
i want to know exactely the component of radial turbine and hwo to cooling it thanks

ME July 9, 2007 00:05

Re: radial turbine flow analysis
Hi, Ahmed, thnank u very much for ur response.

It is only rotor and in that case also only one blade passage. There isnt any cooling flow analysis. As I am using very high temp resistant material. It may done, but I am not doing at present. can u tell me which boundary conditions should be applied?

Ahmed emad July 9, 2007 10:53

axial turbine power
sorry please iwant to knwo the percentage of divided the power out from axial turbine 1)Thrust force 2)drive compressor/fan 3)operat accesories

ME July 9, 2007 21:29

Re: axial turbine power
Hi, Ahmed I havent data, as I am developing a test ring for gas turbine, working on radial comp and radial turbine. My interest is only on turbine. So, I havent any data which u want. I have only inlet pressure, temp, efficiency, mach no, aerodynamic and thermal data etc. Pls let me know ur response.

Pankaj July 11, 2007 00:23

Re: axial turbine power
Hi Mr. ME,

You can get many clues from internet,just search for Turbine(or Turbomachinary) CFD analysis.

To start with u can use Static pressure outlet and mass or velocity inlet.Use K-w.Go through the radial compressor tutorial for more clues.

After that u can switch over to Mass flow outlet and Total pressure and total temp inlet and use SST to be more accurate.

ME July 11, 2007 22:47

Re: axial turbine power
Hi Pankaj and Ahmed, Thanks for kind response. Would you please tell me abt bondary mesh for blade passage. Currenly I have found boundary layer thickness based on flat plate formula (assuming blade as flat plate) and have put 30 to 40 cells in that. Is this enough. Should I also try for coulple of runs to check y plus for k-e wall function? Should I take staedy or transient. I am thinking that I shu initially take k-e staedy and with 6000 rpm ( actual speed is 60,000 rpm) . Once I am getting convergence then I will gradually increase rpm. Then I will take RSM or SST staedy an d then I will take transient RSm or SST. Pls let me know that IS this approach right?

Thanks again.

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