LOSS AT IMPACT OF CONFINED STREAMS 



385 



It will be noted that when 6 is large, and particularly where m is 

 small, the v-f term is all important, while for small values of 6 and large 

 values of m the v* term becomes the more important. With large values 

 of m the value of b approximates, as would be anticipated, to unity for 

 I all values of 0. Where 6, and the volumes of streams (1) and (2) are 

 known the above values of a and b enable the value of m for minimum 



Thus if Qi = n Q%, v\ = v 2 , and the loss is 



loss to be calculated, 

 given by 



loss= | a (-^) 2 + " j 



e.g. If 6 = 30 and Qi = 2 Q 2 , i.e. n = 2 

 When m = 1/5, a = '34, fe = '24, . . . loss = '843 ^~ 



b ft. Ibs. per Ib. of stream (2). 



m = 2'0, a = -20, 6 = '35, . . . loss = '550 ~~ 



m = 2-5, a = '15, b = '44, . . . loss = '536 ^ 



a 



m = 3-0, a = -12, b = '52, . . . loss = '573 ^- 



On plotting these values of m against the loss it appears that this is 



r 2 

 minimum when m=Z'5 and then amounts to *536 ~ ft. Ibs. per Ib. of jet 2. 



For values of 6 between and 45 and of m between 1 and 6, the 

 value of m for minimum loss is given by 



^ + J?- ftl 



100 ^ n-4 g 2 j 



The following table indicates how this best value of m varies with 

 and with the ratio of Qi to Q^ 



H.A, 



C G 



