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screech1987 April 6, 2011 18:55

Isentropic Confuddlement
 
I had problem with convergence while modelling the flow in and out of a blade row. So presently doing some hand calcs to check whether the experimental set up reported is correct/my Boundary conditions set up are correct.
The flow can be considered isentropic, being very subsonic and a Re of 1.6e5 at 'nozzle' exit with a design exit Mach number of 0.59. I have flow angles in and out,flow coefficient and a Zweifel Coefficient (Which I am not entirely sure what this is!!). The experiment (T106A) being modelled is a rig test in which wakes are simulated by the movement of bars past the stationary blade row to modell the interactions. I think I have found the passing frequency of these bars and their spacing between each one, attaining blade speed which I can gain a axial inlet velocity from the flow coefficient.

Thus so far I have been able to get Velocities, Pressure and Temperature (both static and total) at blade exit using standard isentropic relationships. But now I am trying to work out the inlet conditions from the exit ones, to see whether my derived inlet conditions from the literature are correct. At the present my mind has gone blank, as all previous work I have done has a few flow condtions defined at inlet to work off in which to find the required Boundary conditions.

Thanks in advance for any help, even if it is just to tell me what a Zweifel coefficient is haha


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