A study of the effect of secondary fluid injection through single nontangential slots on the surface heat transfer in regions near the injection site is presented. The nondimensional parameters governing the heat transfer are obtained from the pertinent differential equations, and experimental results were obtained which cover the range of interest of these parameters for many situations encountered in film cooling applications. The experimental heat transfer rates were obtained from a novel transient test facility, and are presented as ratios of the heat transfer obtained with film injection to the heat transfer obtained with only the single mainstream.

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Fast fracture strength data on slip‐cast reaction‐bonded Si3N4 determined by uniaxial MOR, biaxial ball‐on‐ring tests, and speed of rotational failure measurements were correlated using Weibull statistics and finite‐element techniques. The agreement between predicted and observed values demonstrated the applicability of the Weibull equation.

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Today there is a rapidly growing interest in the use of ceramics for structural applications. In applying structural ceramics it is necessary to estimate the time dependent failure behavior of the material. An analytical method is required to utilize flexural fast fracture and stress rupture data to predict the time dependent behavior of complex structures. This paper proposes an empirical equation to correlate the data. The proposed equation is applied to flexural and spin disk data. The flexural data correlate reasonably well. The spin disk data correlate well if the assumption is made that the stress in the flexural stress rupture specimens of the data base are those of steady state creep.

Hot‐pressed Si3N4 samples were preoxidized and tested in stress rupture. The lifetime of preoxidized samples was compared to samples that were not pretreated; for the test conditions chosen, lifetime was shorter for the preoxidized samples.

which cannot be verified with (he present test facility. However, this generalization seems justified by previous film cooling studies.Depending on the mainstream temperature, the available coolant temperature, and the desired surface temperature, together with the total thermal environment of the part to be cooled, practically any value of 6* could conceivably be of interest. However, in gas turbine applications, the film-air temperature depends primarily 011 the compressor pressure ratio, and the range of interest of 8* will probably be:

A series of duo-density silicon nitride gas turbine rotors have been prepared for testing and tested at Ford Motor Company. The paper reviews the duo-density fabrication process, and covers in detail the rotor preparation process, which includes machining, inspection, and cold proof spinning. The paper describes the hot spin test rig used for the hot testing of the rotors, and summarizes the results of the hot spin test program.