Question

Compressible flow problem:

Your friend has heard that you know all about carburetors, and wants to know how much air is passing through the one in this 1973 Gremlin. You determine that the throat of the carburetor has an area of 2 cm22 and that the pressure at the throat when the engine is running is 89 kPa, on a day when atmospheric pressure is 100 kPa and the temperature is 24 Celsius. What is the mass flow rate of air through the carburetor, in kg/sec? _____

What’s the flow velocity when the flow has expanded to an area of 7.2  cm2 ? _____

You and your friend decide to attach a supercharger to the Gremlin to raise the stagnation pressure and force more mass through the carburetor, but you get carried away and use way too big a supercharger (more like a compressor, actually...). As a result, the stagnation pressure upstream of the carburetor is now 188 kPa, and the stagnation temperature is 75 Celsius; this high pressure results in choked flow at the throat. What is the mass flow rate through the carburetor now, in kg/sec? ____

For the supercharged Gremlin, what would the flow velocity be if the flow expanded supersonically to an area of 7.2 cm2 ? _____

Answer 1