ICING LIMIT AND WET-SURFACE TEMPERATURE VARIATION FOR TWO AIRFOIL SHAPES UNDER SIMULATED HIGH-SPEED FLIGHT CONDITIONS

摘要

Frictional -heating resulting from flight at high speeds effectively, reduces the value of ambient-air temperatures at which is forms on air¬craft surfaces. An experimental study was made of the wet-surface tem¬perature and the stream conditions that result in ice-free surfaces for bodies in flight through icing clouds, and the results-obtained are com¬pared with values calculated using an analytical method. Two symmetrical airfoil models, one of diamond shape and the other of double-circular-arc contour, were used in the investigation. Results are presented for Mach numbers from 0.6 to 1.35 and for pressure altitudes from 25,000 to 40,000 feet.nThe experimental investigation gave values of the wet-surface temperature that were consistently 2° to 4° F higher than the values cal¬culated by the analytical method for all but the foremost part of the airfoils. The analytical method gave conservative results, compared with the experimental results, predicting the initial formation of ice to occur at values of ambient-air temperature up to 12° F higher than were found experimentally. The experiments generally substantiated the analytically determined location of critical regions on the bodies for the, initial formation of ice and provided sufficient agreement with analytical results to prove their validity.