Experimental and numerical investigation of hydrogen combustion in a supersonic flow
Supersonic combustion ramjet, or SCRAMJET, engines are currently being evaluated for the propulsion of hypersonic vehicles. A unique supersonic wind tunnel facility has been built at the Aerospace Research Laboratory to simulate the operation of a SCRAMJET over a range of Mach numbers of 5 to 6.5 and altitudes of 40,000 to 150,000 ft. The tunnel provides high stagnation temperature, clean air in a continuous Mach 2 flow to the combustor where hydrogen is injected and burned. One of the major parameters in the design of the engine is the combustion efficiency, a quantity which is extremely difficult to evaluate directly. Wall pressure and temperature measurements were made on a model combustor in the ARL facility and a one-dimensional, chemical equilibrium, finite difference model was used to infer combustion efficiency. The initial stagnation temperature was maintained around or below 850 K and an inlet static pressure of 1/2 atm, or less. At these relative low temperatures, thermal choking occurred for relatively low equivalence ratios, limiting this parameter to a maximum of 0.1, depending on the injection configuration. A detailed validation of the analytical model requires extensive knowledge of the physical properties of the flowfield. Since reliable, non-intrusive measurements methods are still under development, the results of the combustion efficiency evaluation were compared with a detailed numerical simulation of the flowfield of interest. The numerical simulation used a 3-D full Navier-Stokes program, which includes a finite rate chemistry model to duplicate one of the experimental cases. The calculations were performed on a CRAY - 2S supercomputer at the National Supercomputer Applications Center at NASA Langley. The solution required 35 CPU hours.
- Research Organization:
- Virginia Univ., Charlottesville, VA (United States)
- OSTI ID:
- 6473185
- Resource Relation:
- Other Information: Ph.D. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMBUSTION
EFFICIENCY
RAMJET ENGINES
COMBUSTION PROPERTIES
EVALUATION
COMPUTERIZED SIMULATION
DESIGN
HYDROGEN
MATHEMATICAL MODELS
NAVIER-STOKES EQUATIONS
SIMULATION
SUPERSONIC FLOW
CHEMICAL REACTIONS
DIFFERENTIAL EQUATIONS
ELEMENTS
ENGINES
EQUATIONS
FLUID FLOW
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
NONMETALS
OXIDATION
PARTIAL DIFFERENTIAL EQUATIONS
THERMOCHEMICAL PROCESSES
330103* - Internal Combustion Engines- Turbine