compressible flow in a counterflow nozzle

d.vamsidhar

hello everybody

we in our college are validating a counterflow nozzle in which fluid will be sucked from one side and fluid is allowed to enter form other side .Actually speaking it consists in adition to primary nozzle inlet it has secondary nozzle inlet(gievn as pressure inlet) and secondary nozzle inlet where fluid has to be sucked so it has been given as pressure outlet.Actually the nozzle ,consists of primary nozzle which is then sorrounded by secondary collar.The fluid should be sucked from from the first secondary nozzle inlet (given as pressure outlet condition) ,also and the main jet which enters the nozzle through the primary nozzle inlet at 8 bar and 533K.and since we have to capture shocks we have given Atmospheric domain of 10 nozzle lengths . Whole nozzle length =36cms.Total domain length 360 cms. I have tried with K-E model(rng & standard), sst K-W SST model.Also i varied the pressure initially from the 1 bar to 8 bar and 294.5K to 533k in steps without converging at each step. but i didnot obtain convergence .also i tried various models with giving 102353Pa and ambient condition 101353 Pa. that also i tried but i didnot obtain convergence.only i obtained convergence at first step then it is becoming difficult.are there any special techniques for solving compressible flow in a counterflow nozzle with boundary conditions below 1.primary nozzle inlet(pressure inlet 102353 Pa 294.5K)it has to be varied from 1 bar to 8 bar and temperature has to be increased form 294.5K to 533k. 2.1st secondary nozzle inlet (pressure outlet)at 101353 Pa then decrease to 59000 Pa 3.2nd secondary nozzle inlet(pressure inlet ) same conditions as primary nozzle inlet. 4.pressure far feild sorrounding the nozzle and ambinet at 101353Pa and 294.5 5.Pressure outlet at the end of the domain with ambient pressure of 101353Pa. so if any body has effective solution techniques please answer.

yours sincerely

d.vamsidhar,

centre for rotating machnery design,

MSR School of Advanced Studies,

Bangalore.