1. Engineering
  2. Mechanical Engineering
  3. 2 consider a rocket engine with the convergentdivergent crosssection sketched...

Question: 2 consider a rocket engine with the convergentdivergent crosssection sketched...

Question details

2 Consider a rocket engine with the convergent-divergent cross-section sketched in Figure Q2. The nozzle is fed from a combustion chamber which acts as a reservoir where the stagnation pressure and stagnation temperature are 10 MPa and 1000 K. The divergent passage discharges into a downstream chamber connected to an evacuation pump and valve, where the back pressure can be varied between 10 MPa and vacuum. The throat and exit areas are 0.1 m2 and 0.4 m2 respectively. Downstream chamber Hot Gases Figure Q2 (a) Calculate the range of back pressures in the downstream chamber which create the (i) subsonic; (ii) non-isentropic; (ii) over-expansion; and (iv) under- expansion flow regimes. Assume that the working fluid is calorically-perfect air (i.e., constant specific heats at all temperatures) and that the flow, apart from the existence of shock waves, is isentropic throughout the nozzle. [15 marks] (b) Sketch, qualitatively, the exhaust-flow patterns for the over-expansion and [5 marks] under-expansion flow regimes, and discuss salient features. (c) Estimate the mass flow rate through the nozzle for the case where the back [5 marks] pressure is a vacuum.

Solution by an expert tutor
Blurred Solution
This question has been solved
Subscribe to see this solution