solhw5 - MAE135 SOLUTIONS TO HW 5 Spring 2010 PROBLEM 1(10...

This preview shows pages 1–2. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MAE135 SOLUTIONS TO HW 5 Spring 2010 PROBLEM 1 (10 points) In the case where heat transfer is ignored, and since flow is frictionless, both p and T are preserved. The pressure ratio across the injector, p 1 /p a =3 is more than sufficient (higher than 1.893) to create choked flow at the exit. Therefore, ˙ m = C p * √ T * = C p 1 radicalbig T 1 where C includes the area and all the gas-dynamic constants in the mass flow rate expression. Heating the injector tube has two effects: increasing T and decreasing p . Assuming the exit is choked (we will need to verify this) we use the table for frictionless 1D flow with heat transfer: T T * = 0 . 5 → p p * = 1 . 114 The pressure ratio at the injector exit is p * /p a =3.0/1.114=2.693 which is still above the critical value 1.893. So the assumption of sonic flow was correct, and we can still use the sonic mass flow rate relation ˙ m = C p * √ T * = C p 1 / 1 . 114 radicalbig 2 * T 1 = 0 . 635 C p 1 radicalbig T 1 So the actual mass flow rate is 0...
View Full Document

{[ snackBarMessage ]}

Page1 / 2

solhw5 - MAE135 SOLUTIONS TO HW 5 Spring 2010 PROBLEM 1(10...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online