21 research outputs found
Temperature Histories in Ceramic-Insulated Heat-Sink Nozzle
Temperature histories were calculated for a composite nozzle wall by a simplified numerical integration calculation procedure. These calculations indicated that there is a unique ratio of insulation and metal heat-sink thickness that will minimize total wall thickness for a given operating condition and required running time. The optimum insulation and metal thickness will vary throughout the nozzle as a result of the variation in heat-transfer rate. The use of low chamber pressure results in a significant increase in the maximum running time of a given weight nozzle. Experimentally measured wall temperatures were lower than those calculated. This was due in part to the assumption of one-dimensional or slab heat flow in the calculation procedure
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NACA Research Memorandums
Report presenting thrust-reversal performance of several basic target-type jet reflectors of various sizes and with various modifications obtained with unheated air over a range of exhaust-nozzle pressure ratios. Maximum, or near maximum, reversal for any deflector occurred at a spacing which was mechanically feasible and did not affect nozzle air flow
Effect of Inlet Air Distortion on the Steady-State and Surge Characteristics of an Axial-Flow Turbojet Compressor
An investigation was conducted in an altitude test chamber to determine the effects of inlet airflow distortion on the compressor steady-state and surge characteristics of a high-pressure ratio, axial-flow turbojet engine. Circumferential-type inlet flow distortions were investigated, which covered a range of distortion sector angles from 20 deg to 168 deg and distortion levels up to 22 percent. The presence of inlet airflow distortions at the compressor face resulted in a substantial increase in the local pressure ratio in the distorted region, primarily for the inlet stages. The local pressure ratio in the distorted region for the inlet stages increased as either the distortion sector angle decreased or the percent distortion increased. The average compressor-surge pressure ratio was much more sensitive to inlet airflow distortions at lower engine speeds than at engine speeds near rated. Hence, compressor-surge margin reduction due to inlet airflow distortion was quite severe at the lower engine speeds. Although the average compressor-surge pressure ratio was generally reduced with inlet flow distortion, local pressure ratios across the distorted sector of the compressor were obtained during surge and were significantly greater than the normal compressor-surge pressure ratio. This was a result of increased loading of the inlet stages in the distorted region
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NACA Research Memorandums
"An investigation was conducted in an altitude test chamber to determine the effects of inlet airflow distortion on the compressor steady-state and surge characteristics of a high-pressure ratio, axial-flow turbojet engine. Circumferential-type inlet flow distortions were investigated, which covered a range of distortion sector angles from 20 deg to 168 deg and distortion levels up to 22 percent. The presence of inlet airflow distortions at the compressor face resulted in a substantial increase in the local pressure ratio in the distorted region, primarily for the inlet stages" (p. 1)
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NACA Research Memorandums
Memorandum presenting a performance investigation using hydrogen fuel in a full-scale afterburner conducted with particular study of fuel-injector configurations and afterburner length. A total of seven fuel-injector configurations, grouped by type as concentric ring or radial bar, were investigated at a specified burner-inlet velocity and range of burner-inlet total pressures