Problem Statement: A box-enclosed fan is pushing air downwards through a 1 m diameter blade span area. The whole system

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Problem Statement A Box Enclosed Fan Is Pushing Air Downwards Through A 1 M Diameter Blade Span Area The Whole System 1 (118.56 KiB) Viewed 36 times

Problem Statement: A box-enclosed fan is pushing air downwards through a 1 m diameter blade span area. The whole system weighs 20 N and does not rotate. In order for the system to hover mid-air (i.e. stay stationary in the air), determine the following: . Consider g = 9.81 m/s2, and Pair = 1.25 kg/m3 • What are the valid assumptions (select all valid choices)? • What is the air exit velocity required? . What is the volumetric flow rate needed? • Hint: The inlet air speed is very small due to sucking stationary air from the surrounding. If the system is to accelerate upwards at constant value of 20 m/s2, determine the following: • Consider g - 9.81 m/s² and Pair - 1.25 kg/m3 • What is the new air exit velocity needed? • What is the increase in the air exit velocity? • Hint 1: The inlet air speed is very small due to sucking stationary air from the surrounding. • Hint 2: Use the conservation of linear momentum with accelerating control volume equation provided below: 8, +,- Secrop p dv = , Vp dv +[vpvdå Select a total of 8 answers that match the above required quantities with the best approximations. Select B correct answer(s) Compressible Flow Vincrease - 1.42 m/s Atmospheric pressure all around the control volume 7.87 m/s Non-uniform Velocity Profile across Control Surfaces 06.89 m/s Vincrease - 3.36 m/s Vincrease - 5.87m/s 06.12 m/s 3.54 m3/s 12.1 m/s ООО Incompressible Flow Steady Flow Uniform Velocity Profile across Control Surfaces 2.5 m/s Atmospheric pressure only at the outlet of the control volume 9.84 m/s Unsteady Flow 4.51 m/s 10.1 m/s