


3. (15 marks) Consider a supersonic flow of air through a small, 7 cm diameter tube...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow rate of 0.005 kg/s and a temperature of 30°C. The tube is of diameter D =60mm, and fully developed conditions with h = 30W/m2K exist over the entire length of L-4m. Take cp-1015 /kg.K 2 (a) (10pts) For the case of uniform surface heat flux at q"-1000W/m, determine the total heat transfer rate q and the mean temperature of the air leaving the tube...
part b only please8.12 Dry, compressed air at Tm,i 75°C, p- 1o atm, with a mass flow rate of a 30-mm-diameter, 5-m-long tube whose surface is at T, 25°C. 0.001 kg/s, enters (a) Determine the thermal entry length, the mean temperature of the air at the tube outlet, the rate of heat transfer from the air to the tube wall, and the power required to flow the air through the tube. For these conditions the fully developed heat transfer coefficient is...
8.12 Dry, compressed air at Tm.i75°C, p-10 atm, with a mass flow rate of 0.001 kg/s, enters a 30-mm-diameter, 5-m-long tube whose surface is at Ts - 25°C. (a) Determine the thermal entry length, the mean temperature of the air at the tube outlet, the rate of heat transfer from the air to the tube wall, and the power required to flow the air through the tube. For these conditions the fully developed heat transfer coefficient is h- 3.58 W/m2...
A counter-flow heat exchanger is stated to have an overall heat transfer coefficient of 284 W/m2.K when operating at design and clean conditions. Hot fluid enters the tube side at 101°C and exits at 71°C, while cold fluid enters the shell side at 27°C and exits at 42°C. After a period of use, built-up scale in the heat exchanger gives a fouling factor of 0.0004 m2 K/W. The surface area is 93 m². Assume both hot and cold fluids have...
Waste heat of exhaust hot air from a manufacturing process may be recovered by passing water through a thin-walled tube of 1.00 cm diameter as shown. Assume the temperature of the hot air is 177℃ in cross flow with a velocity of 20 m/s over the tube. The inlet and outlet temperature of water are 20C and 60 C, rospectively, and the ilow rate is 0.2 k/s. Deiemine (a) the total heat transfer rate from air to water, (b) The...
QUESTION 4 (25 marks) Water (Cr 4.208 kJ/kg.K) at flow rate of 5.11 kg/s s heated from 78°C to 98°C in an economizer inside a boiler. The boiler is a cross flow heat exchanger with single pass, shell fluid mixed and other fluid unmixed. The average water velocity in the 1.5 cm diameter (D) tube is 1.27 m/s. On the shell side, hot air (C,-1.0341 kJ/kgK) was used as the heating fluid with 7.3 kg/s of it entering the exchanger...
please solve it quickly
ignore p=75
Problem 3 Part a P=57 Moist air enters the cooler of an air conditioning unit at 25 °C and a relative humidity of 70%. The cooled and dehumidified air leaves the cooler saturated at 18 °C. The temperature of condensed water is 18 °C. The pressure is constant at 101.325 kPa. The mass flow rate of the dry air is mda=67 kg/s. Use the psychometric chart to determine a) The humidity ratio at the...
1. Water enters the constant 130-mm inside-diameter tubes of a boiler at 7 MPa and 65°C and leaves the tubes at 6 MPa and 450°C with a velocity of 80 m/s. Calculate the velocity of the water at the tube inlet and the inlet volume flow rate. [5-14] 2. Air enters a nozzle steadily at 50 psia, 140°F, and 150 ft/s and leaves at 14.7 psia and 900 ft/s. The heat loss from the nozzle is estimated to be 6.5...
An aligned tube bank is constructed of 2.5-cm-diameter tubes with 15 rows of tubes with 7 tubes in each row. The tubes are maintained at 90°C, and atmospheric air is blown across them at 20°C and u00-12 m/s. The arrangement has S 3.75 cm and SL = 5.0 cm. Calculate (a) the heat transfer from the tube bank per meter of length, and (b) the air- side pressure dropkP
An aligned tube bank is constructed of 2.5-cm-diameter tubes with 15...
hair dryer may be idealized as a circular duct through which a
small fan draws ambient air and within which the air is heated as
it flows over a coiled electric resistance wire.
(1) If a dryer is designed to operate with an electric power
consumption of Pelec= 1500 W and to heat air from an ambient
temperature of Ti= 20°C to a discharge temperature of To= 45°C, at
what volumetric flow rate ∀˙ should the fan operate? Heat loss...