Thanks. Yes as I said I need to fine tune the model. Both SFC values are off by quite a bit. And there is no stage matching. I have modified some of the constraints in new model yesterday. Still need to add more. And need to include blade cooling model too. As of now its just primitive model with assumption that cooling flow reached HPT exit conditions without losses. No account of accessories work off take which is like 10% of HPT output. And some more details.vina wrote:Just posting this from the figures that I have from my spreadsheet & calculations.JayS wrote:Madhu,
here is a summary of the Kaveri parameters from my set of calculations. I am yet to do the stage matching and thus the W numbers are out of sync. But I realised that the specified PR values cannot be taken as constants and would need to be varied to converge the calculations.
This is for uninstalled thrust. The SFC values are on higher sides. I need to fine tune the model further.
The fan exit temp I have is 426.79K, with an eta (assumed) of 0.85
HPC exit temp is 776.43K (eta of 0.85)
The TSFC of the current Kaveri is 23.63 g/KNs per my calculation. This is very close and in the ball park of EJ200 dry thrust figure of 23 g/KNs. I think my calculated numbers are good. The number you have for TSFC (dry) is around 26.3 g/KNs , which seems off by around 10% . The TET should be limited to 1400K in ISA conditions as per the GTX cycle.
Some of the difference in your values and mine would be due to differences in Cp and Gamma values. I need to encode them as polynomial function of T. As of now I just took aprox numbers from a table.