Hydraulics and Pneumatics

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1. State all assumptions and determine friction loss in a concrete pipe (L = 3000 ft, D = 1 ft) that carries 12 cfs of water at 140°F. a) Use Darcy-Weisbach equation b) Use Hazen-Williams equation d) Briefly explain why selection of a design value for pipe roughness is appropriate for new pipe c) Briefly explain any difference between energy loss calculated by both methods


A circular hydrostatic bearing with an outside diameter of 150 [mm], recess diameter of 60 [ mm] and rotating at 500 [rpm] supports a load of 50 [kN]. The bearing is lubricated by a mineral oil of density p = 900 [kg/m] delivered to the bearing by a constant flow rate delivery pump operating at 50×10* [m°s"].The operating temperature of the bearing is 30°C. calculate the recess pressure and select an SAE oil such that the film thickness will never be less than 10 [um]. (Ans.P, = 6.173 [MPa], SAE20)


3. Find the size of the struts required to restrain the fitting. The fitting is part of a refinery that processes gasoline (S=0.68). The struts are made of a material having an allowable stress of 2.5 Ksi. The weight of the fitting is 3,000 lbs.Though the fitting is curved, the size of the fitting transitions uniformly over its 12 foot length. Assume no losses through the fitting. The discharge through the fitting is 5,000 Gpm.


A piece of plastic floats in water with 44% of its volume below the water line. What is its density in units of kg/m³? If this is on an elevator that is accelerating up at a rate of 2.47 m/s², what percent is below the water line? (Enter no units for the second answer.)


A 3.73-m long thin seesaw with a mass of 43.7 kg has a pivot in its center. Two children with masses 35.9 kg and 30.7 kg sit on extreme opposite ends and start moving up and down. When the seesaw is horizontal and neither child is in contact with the ground, what is the magnitude of the net torque acting on the board (use units of N*m)? What is the magnitude of the angular acceleration of the seesaw at this instant (use units of rad/s^2)?


1In this problem, we consider two actuators connected in parallel and in series. Capside area of each actuator = Acap = 2A Rodeside area of each actuator = Arod = A%3D The viscous friction force in each actuator: Actuator 1: F, = b, v, Actuator 2: F2 = b2 V2 where v,and v, are the velocities of the respective actuators. a) The figure below shows the two actuators connected in parallel driven by variable flow pump.a Determine the relationship between pump flow Q and pump pressure p (interms of b,, b, and A) • Sketch p vs Q Assuming b, > b2 which actuator moves faster? b) Figure below shows the two actuators connected in series also driven by a variable flow pump. Find actuator speeds v, and v, as functions of pump flow Q Find relationship between p and Q and sketch p vs Q.


2. A storage tank discharges water @ 20°C through a galvanized iron pipe (L = 25 m, D = 150 mm).Ignore minor loss and assume pipe is horizontal. a) Calculate required depth of water above pipe outlet to deliver 0.10 m³/sec to customers b) Estimate pressure (kPa) in middle of discharge pipe.


4. The hydraulic system shown below operates for a total of 30 seconds at which point all flow within the system ceases. Assuming that the tank is initially empty, what is weight of the fluid in the tank?


A hydraulic lift has two cylindrical portions, one with a radius of 0.95 m and the other with a radius 0.25 m. Suppose there is a car of mass 1893 kg placed on the platform associated with the larger cylinder. What is the magnitude of the minimum force needed on the side of the smaller cylinder to keep the car lifted above ground? If the car is raised 0.39 m above ground, how far does the piston in the small cylinder have to move?


For the bearing specified in problem 6.11 calculate the percentage in load increase that would cause a 20 percent decrease in film thickness


A pump capable of maintaining 20 [MPa] of pressure is supplying oil of viscosity 80 [cP] to a circular hydrostatic thrust bearing of an outside diameter of 0.1 [m] at a rate of 0.4x10* [m/s], generating a steady film thickness of 30 [um]. The bearing supports a weight of 60 [kN] and rotates at 1,000 [rpm]. Calculate a suitable recess radius and pumping power. (Ans. R, = 0.0285 [m], H= 50.89 [W])


2. Find the force in the X and Y direction required to hold the fitting in place. The fitting lies in the horizontal plane. Assume steady-state conditions and you may assumes that pressures in the fitting are so low that they do not contribute to the restraining forces, i.e. neglect the effect of pressure.


A U-shaped manometer has three liquids within it. The liquid in the bend of the tube is mercury; the height of the column of mercury on the left equals the height of the column of mercury on the right. This liquid above the mercury on the left has a height of 9.69 cm and a density of 780 kg/m³. The liquid on the right has a height of.25 cm. What is the density of the liquid on the right? The top of the liquids on both the left and right are exposed to the atmosphere. Enter the units as kg/m^3.


Using this density, what is the change in pressure AP for a diver going from a depth of 74.7 m to a depth of 50.5 m? Enter units of Pa.


1. Determine the operating point andrequired input power for the pump underthe stated conditions (assume efficiency= 70%). The pump curve appears below


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