THE AMES ATMOSPHERE ENTRY SIMULATOR AND ITS APPLICATION TO THE DETERMINATION OF ABLATIVE PROPERTIES OF MATERIALS FOR BALLISTIC MISSILES

摘要

The atmosphere entry simulator at the Ames Research Center is described. It is demonstrated that the motion and heating of long-range ballistic missiles can be simulated with small-scale models in this facility. Results are also presented of tests to determine the feasi¬bility of ethyl cellulose plastic as an ablative material for long-range ballistic missiles. The test models consisted of spherically tipped cone cylinders of 0.788-inch diameter and tip radii equal to one-fourth the diameter. The cone half-angle was 50° and the models weighed 4.3 grams (0.0095 pound). The tests simulated the motion and heating of ballistic missiles with atmosphere entry velocities ranging from 10,000 to 21,500 feet per second, with diameters varying from 4.5 to 5.4 feet, with weights varying from 3150 to 5500 pounds, and with ranges varying from 640 to 4150 statute miles, respectively.nIt was deduced that flow over the model was predominately turbulent at entrance velocities in excess of 14,000 feet per second. A relation is presented for the effective heat capacity of ablating materials in turbulent flow as a function of local enthalpy. This relation is employed in conjunction with the test results for the ablation weight losses to estimate the effective heat of ablation for ethyl cellulose.