Expert: Paul Soderman - 5/18/2006

Question
hi paul.  im a mechanical engineer in the polymer sector by trade, but have been asked by by my nephew now studing engineering a turbofan question and need a little help

His question reads

An aircraft powered by turbofan engines cruises at a Mach No. of 0.82, at an altitude where Ta = 223.3K and Pa = 0.265 bar. Each engine has a by-pass ratio of 4.8 and a total mass flow rate of 210 kg/s at these conditions. The fan pressure ratio is 1.75 and the fan efficiency is 97%. The intake efficiency is 94% and the by-pass nozzle efficiency is 100%.
Calculate the thrust from one of the engines produced by the by-pass air alone.

now i understand that the thrust is going to be a combination of the bypass and the main core thrust.I can get the compressor work but the problem which i am having is figuring the turbine entry temperature.


much appreciated
regards

Answer
Hi Emmett

As an aerodynamicist, I don't have much experience with turbomachinery and my jet engine book is missing.  Marks Handbook says that gas turbine inlet temperatures range from 1200 to 1800 deg. F, but I don't know if that is much help to your problem.  Sorry.

Paul