A compressor is designed to run at N1 4800 RPM and mass flo

A compressor is designed to run at N1 = 4800 RPM and mass flow of 66 kg/s. The ambient conditions for the design point are 101kPa and 16C. However, the performance characteristics of the compressor were tested when the ambient temperature was 30C. A) What is the speed at which the compressor must run during the test? B) If inlet pressure of 82kPa is obtained during normal ambient condition, calculate the mass flow rate obtained during the test

Solution

Given,

N₁ = 4800 rpm

M₁ = 66 kg/s

P_a = 101 kpa

T_a = 16 = 289 k

T₂ = 30 = 303 k

N*D/sqrt(T*R) characteristic will be same for compressor.

N₁*D/sqrt(T_a*R) = N₂*D/sqrt(T₂*R)

N₂ = 4915.2 rpm

M*sqrt(T*R)/(P*D^2) characteristic will be same for compressor.

M₁*sqrt(T₁*R)/(P₁*D^2) = M₃*sqrt(T₃*R)/(P₃*D^2)

Here, P₃ = 82 kpa & T₃ = 289 k given in que.

M₃ = 53.5842 kg/s