Accession Number:

ADA230850

Title:

Evaluation of Air Injection in a Sudden Expansion Diffuser for Real-Time Afterburning Application

Descriptive Note:

Final rept. 22 Jan-5 Apr 1989

Corporate Author:

ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN

Personal Author(s):

• Stephens, S. E.

Report Date:

1991-01-01

Pagination or Media Count:

85.0

Abstract:

Altitude testing of advanced hydrogen-fueled propulsion systems will require techniques to deal with unburned hydrogen in the engine exhaust stream. One approach is real-time afterburning. This approach would inject oxidizer in the test facility exhaust diffuser and burn off the excess hydrogen before it reached any facility machinery. A combined experimental and computational study was conducted to evaluate the feasibility of this approach. The experimental study tested a sudden expansion diffuser with injection both upstream and downstream of the step. Engine air was delivered through either a Mach 3.0 or 0. 8 nozzle The acquired data evaluated mixing of the nonreacting streams using measured temperatures and a Crocco relationship. Wall and pitot pressures were used to evaluate diffuser performance. The PARC computer programs was used to predict the flow field two test conditions. The results showed that good mixing can be obtained with the configuration at penalty of loss in maximum diffuser pressure rise. The PARC program did an excellent job of predicting the flow-field pressures and shock structure however, it was less satisfactory for predicting mixing based on temperature distribution.

Descriptors:

• *AFTERBURNING
• AIR
• ALTITUDE
• COMPUTATIONS
• COMPUTER PROGRAMS
• DIFFUSERS
• DISTRIBUTION
• ENGINES
• EXHAUST DIFFUSERS
• EXPANSION
• FACILITIES
• FLOW FIELDS
• FUELS
• HYDROGEN
• INJECTION
• MACHINES
• OXIDIZERS
• PENALTIES
• PERFORMANCE(ENGINEERING)
• PITOT TUBES
• PRESSURE
• PRESSURE GRADIENTS
• PROPULSION SYSTEMS
• REAL TIME
• SHOCK
• STREAMS
• TEMPERATURE
• TEST AND EVALUATION
• TEST FACILITIES

Subject Categories:

• Test Facilities, Equipment and Methods
• Combustion and Ignition
• Liquid Propellant Rocket Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE