As a means of preventing ice formation on the wings of a small, private aircraft, it is proposed that electric resistance heating elements be installed within the wings. To determine representative power requirements, consider nominal flight conditions for which the plane moves at 100 m/s in air that is at a temperature of
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Fundamentals of Heat and Mass Transfer
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- A car with passengers has a mass of 1200 kg and a frontal area of 1.8 m. It is traveling up a gradient of 1 in 25 at a speed of75 km/h. The rolling resistance of the car is given by R, = (0.0112 + 0.00006 V) Mg and the air resistance coefficient is 0.02688. The engine develops 50 kW corresponding to an engine speed of 4500 rpm. The rear axle ratio is 5:1 and the transmission efficiency is 96%. If the wheel radius is 340 mm, determine the 1. tractive resistance 2. tractive effort available at the wheels and 3. acceleration while moving up the gradientarrow_forwardCharacteristic curves are available for a fan running at 850rpm and passing air of inlet density 1.2 kg/m3. Readings from the curves indicate that at an airflow of 150 m³/s, the fan pressure is 2.2 kPa and the shaft power is 440 kW. If the efficiency remains unchanged, calculate the corresponding points if the fan is run at 1100 rpm in air of density 1.1 kg/m³.arrow_forwardA velomobile is a bicycle or tricycle with a full aerodynamic fairing. The aerodynamics of a velomobile are far better than a cyclist on a typical mountain bike. We are going to assume the rider has a mass of 70 kg.arrow_forward
- The friction coefficient for a boundary layer is given by the expression: Cf = 1.32 √ReT If the average flow velocity increases from an original state to a new state by a factor of 3.38, calculate the ratio of the Cf over its value at the original state.arrow_forwardAn aircraft has a total mass of (1.26x10^2) kg and a wing area of (1.800x10^1) m2. It operated with an aerofoil section having C = 1.0 and CD=0.1. Assuming that the total drag of the wing represents the whole drag of the aircraft, find the power input required for to overcome gravity and take off. Assume density of air to be 1.2 kg/m3. Answer should be in Watts with three significant figures. Note: Your answer is assumed to be reduced to the highest power possible. Your Answer: x10 Answerarrow_forwardI1arrow_forward
- B1arrow_forwardRequired information A disk-gap-band parachute has a drag of 1600 lbf when tested at 15 mi/h in air at 20°C and 1 atm. The diameter of the parachute is 43 ft. For air at 20°C and 1 atm, take p≈ 1.20 kg/m³. Take π = (22/7). If the drag on Mars is 65,000 lbf and the velocity is 1300 mi/h in the thin Mars atmosphere and p≈ 0.020 kg/m³, what is the drag coefficient on Mars? The drag coefficient isarrow_forwardQs. An aircraft is flying in level flight at a speed of 200 km/h through air (density, p = 1.2 kg/m³, and viscosity, μ = 1.6 x 10-5 N-s/m²). The lift coefficient at this speed is 0.4 and the drag coefficient is 0.0065. The mass of the aircraft is 800 kg. The effective lift area of the aircraftarrow_forward
- Consider a Boeing 747 airliner cruising at a velocity of 550 mi/h at a standard altitude of 38,000 ft, where the freestream pressure and temperature are 432.6 lb/ft2 and 390 R, respectively. A one-fiftieth scale model of the 747 is tested in a wind tunnel where the temperature is 430 R. Calculate the required velocity and pressure of the test airstream in the wind tunnel such that the lift and drag coefficients measured for the wind-tunnel model are the same as for free flight. Assume that both u and a are proportional to T 1/2. Let subscripts 1 and 2 denote the free-flight and wind-tunnel conditions, respectively. For C C2 and Co1 = Co2, the wind-tunnel flow must be dynamically similar to free flight. So, M, = M2 and Re, = Re,. %3D %3Darrow_forward3. A truck has a drag coefficient based on frontal area of CD = 0.86. The truck has a mass of 12,750 kg and a frontal area of 10.5 m2. If the truck is traveling at constant speed on a level road, the forces retarding its forward progress are the drag and the rolling friction. The force due to rolling friction can be written as Fit Wfr(1+ V V₁ where V is the truck speed in m/s, Vo = 30 m/s and fr (the coefficient of rolling resistance) is approximately 0.008 for a truck on concrete or asphalt. Plot the total power the engine must supply as a function of truck speed, V. Comment on the relative importance of drag and rolling friction in the fuel consumption of the truck.arrow_forwardA jet airplane weighs 160,000 N and has a zero-lift drag coefficient of 0.008 and a wing area of 42 m2. At 100 m/s at sea level, the rate of climb is 11.5 m/s. The thrust developed by the engines is equal to 27,000 N. Determine the maximum rate of climb and the corresponding flight speed at sea level . [Answer: 21.6013 m/s and 214.5577 m/s]arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning