AT&T; 10:19 AM 69% Hw #3 Due on Oct 18, 2017-Referenc 5, Detail Submission Grade

Question

AT&T; 10:19 AM 69% Hw #3 Due on Oct 18, 2017-Referenc 5, Detail Submission Grade HW #3 Due on Oct 18, 2017 Reference Chapter 5, 6 and 7 Due: Oct 18, 2017 at 9:00 PM 1. A pump has a displacement volume of 10 cubic inches. It delivers 25 gpm at 850 rpm and 995 psi. If the prime mover input torque is 2000 in lb. a) What is the overall efficiency of the pump? b) What is the theoretical torque required to operate the pump? 2. A gear pump has a 4-in outside diameter, a 1-in inside diameter, and a 1-in width. If the actual pump flow at 1500 rpm and rated pressure is 100 gpm, what is the volumetric Courses Calendar To Do Notifications Inbox

Explanation / Answer

1. (a) The overall efficiency can be calculated by calculating the Mechanical Efficiency and Volumentric Efficiency

Theoretical flow = displacement x driven speed = 10 x 850 = 8500 in^3 per minute

Actual Flow = 25 gpm = 25 gallons per minute = 5775 in^3 per minute (Considering 1 US gallons = 5775 cubic inch)

Therefore, Volumetric efficiency = (Actual Flow)/(Theoretical Flow) = 0.67 = 67%

Theoretical Torque = Operating Pressure x displacement per minute / 2pi = 995 psi * 10 in^3 /2pi = 1583.59 in lb

Actual Torque = 2000 in lb

Hence Mechanical Efficiency = (Theoretical Torque)/(Actual Force) = 1583.59/2000 = 0.792 = 79.2%

Therefore the overall efficiency is Mechanical Efficiency x Volumetric Efficiency = 0.62 x 0.792 = 0.491

(b) The theretical torque is calculated in above question

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