G,6 • COMPARISON WITH EXPERIMENTAL RESULTS 



from the leading edge) was made at the Polytechnic Institute of Brooklyn 

 [43]. Fig. G,6c shows that good agreement has been obtained between 

 the measured velocity profiles and those calculated from the theoretical 

 results given in [7]. The heat transfer theory in the laminar boundary 

 layer can therefore be considered to have been verified, at least for a low 

 rate of heat transfer. Due to the roughness and jet effect of the injected 

 velocity of the porous plate, only qualitative agreement is obtained be- 

 tween the measured transition Reynolds number and those predicted 

 from the laminar boundary layer stability theory [25]. 



I 



D 



Theoretical curve [7] 

 Experimental X 

 Data (CIT) 



t- 



I 3 



^X103 



Fig. G,6b. Comparison of measured data in a stainless-steel 

 specimen with theoretical result [7]. (From [37].) 



An extensive experimental study of transpiration cooling of turbulent 

 pipe flow with injection is being conducted at the Polytechnic Institute 

 of Brooklyn under the auspices of Project Squid. The investigation has 

 been guided by the theory discussed in Art. 5. The experimental apparatus 

 for this investigation was designed and so arranged that fully developed 

 turbulent flow would be established upstream of the test section. Hence 

 any change in the flow conditions in the porous test section would be due 

 to mass injection. The porous stainless steel segment, made by the Poroloy 

 method, is a five-inch-diameter circular pipe, 24 inches in length. The 

 velocity and pressure surveys were made at six stations along the axial 

 direction of the porous-wall pipe. For zero injection at the wall the meas- 

 ured velocity profiles (10^ ^ Re ^ b X 10^) are in good agreement with 

 Nikuradse's measurement for the smooth pipe. A comparison of the 

 measured velocity profiles with various injection velocities to the theo- 

 retically calculated velocity profiles is given in Fig. G,5f. 



< 477 ) 



