In a geothermal power plant, the used geothermal water at 80°C enters a 15-cm-diameter and 400-m-long un insulated pipe at a rate of 8.5 kg/s and leaves at 70°C before being reinjected back to the ground. Windy air at 15°C flows normal to the pipe. Disregarding radiation, determine the average wind velocity in km/h.

In a geothermal power plant, the used geothermal water at 80°C enters a 15-cm-diameter and 400-m-long un insulated pipe at a rate of 8.5 kg/s and leaves at 70°C before being reinjected back to the ground. Windy air at 15°C flows normal to the pipe. Disregarding radiation, determine the average wind velocity in km/h.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.65P

See similar textbooks

Similar questions

Air enters a 7-m-long section of a rectangular duct of cross section 15 cm X 20 cm at 50°C at an average velocity of 7 m/s. If the walls of the duct are maintained at 10°C, determine: (a) the outlet temperature of the air, (b) the rate of heat transfer from the air, and (c) the fan power needed to overcome the pressure losses in this section of the duct.
In a geothermal power plant, the used geothermal water at 80°C enters a 15-cm-diameter and 400-m-long uninsulated pipe at a rate of 8.5 kg/s and leaves at 70°C before being reinjected back to the ground. Windy air at 15°C flows normal to the pipe. Disregarding radiation, determine the average wind velocity in km/h.
Consider that a flow of air with a velocity of 270 m/s enters an adiabatic diffuser at a pressure of 60 kPa and a temperature of 7°C and exits the diffuser at a pressure of 85 kPa and a temperature of 27°C. Use variable specific heat approach to indicate the air properties. Calculate the ratio of the inlet area to the exit area of the nozzle.
Air at 60°C leaves a furnace and passes through a 12-m long, 20-cm × 20-cm square duct at an average velocity of 4 m/s. If the duct has a constant surface temperature of 33°C, determine the exit temperature of the air and the rate of heat transfer.
Metal plates (k = 150 W/m·K, ρ= 2800 kg/m3, and cp = 900 J/kg·K) with a thickness of 2 cm exiting an oven are conveyed through a 10-m long cooling chamber at a speed of 4 cm/s, as shown in the figure. The plates enter the cooling chamber at an initial temperature of 500°C. The air temperature in the cooling chamber is 15°C, and the plates are cooled with blowing air and the convection heat transfer coefficient is given as a function of the air velocity h(V) = 33V0.8, where h is in W/m2·K and V is in m/s. To prevent any hazard to workers handling the plates, it is necessary to design the cooling process such that the plates exit the cooling chamber at a relatively safe temperature of 50°C or less. Determine the air velocity V and the heat transfer coefficient h such that the temperature of the plates exiting the cooling chamber is at 50C.
A U-tube open at both ends is partially filled with water. Oil having a density of 750 kg/m3 is then poured into the right arm and forms a column L = 10.00 cm high. The density of air is 1.29 kg/m3.The right arm is then shielded from any air motion while air is blown across the top of the left arm until the surfaces of the two liquids are at the same height. (d) Determine the pressure difference between the water and oil columns(e) Determine the speed of the air being blown across the left arm.
A one ton car is initially travelling at 10 kph when it combusts 50 grams of fuel with calorific value of 15,000 kJ. If rolling friction and air drag is negligible, and the efficiency in converting the heat of the fuel to kinetic energy is 25%. Determine the final velocity of the car in kilometers per hour.
The cross section of the rectangular duct of the heating system is 15 cm x 20 cm (figure shown below), with 6-m-long section of an air heating system of a house passes through an unheated space in the basement. Hot air enters the duct at 100 kPa and 60°C at an average velocity of 6 m/s. The temperature of the air in the duct drops to 54°C as a result of heat loss to the cool space in the basement. Determine the rate of heat loss from the air in the duct to the basement under steady conditions. Also, determine the cost of this heat loss per hour if the house is heated by a natural gas furnace that has an efficiency of 80 percent, and the cost of the natural gas in that area is $0.70/therm (1 therm = 100,000 Btu = 105,500 kJ).
A 4-m x 4-m flat plate maintained at a constant temperature of 80°C is subjected to parallel flow of air at 1 atm, 20°C, and 10 m/s. The total drag force acting on the upper surface of the plate is measured to be 2.4 N. Using momentum heat transfer analogy, determine the average convection heat transfer coefficient, and the rate of heat transfer between the upper surface of the plate and the air
A fan is used to transport CO2 gas (MW = 44 g/mol) gas at rest @ 700mmHg. At the discharge end, the pressure is 765mmHg, and the velocity is 100 m/s. Assuming the flue gas behaves ideally, and the process is isothermal, with the temperature maintained at 100C. Determine the theo. power required to move 45000 m /h of the flue gas.
What is the effect of heat gain and heat loss on the entropy of the fluid during Rayleigh flow?
Is the sonic velocity in a specified medium a fixed quantity, or does it change as the properties of the medium change? Explain