The net positive suction head required (npshr) by a pump may be expressed approximately as parabolic function of volume flow rate. the npshr for a particular pump operating function of volume flow rate. the npshr for particular pump operating at 1800 rpm is given as = h0 + 2 (h0 = 10 ft, a= 7.9 ft/ ). assume the pipe system supplying pump suction consists of a reservoir, whose surface is 22 ft above the pump centerline, a square entrance, 20 ft of 6 in cast-iron pipe, and 90°elbow. calculate the maximum flow rate at 70℉ for which the suction head is sufficient to operate this pump without cavitation.