air is flowing inside of a pipe with radius=0.4 meters at a mass velocity of 29.4 kg/s*m2 at 322 K, with the walls of the pipe at 300 K. At the conditions of the experiment, the viscosity of air is 1.984 x 10-5 Pa*s, the density of air is 1.22 kg/m3, the heat capacity is 1 kJ/kg*K, and the thermal conductivity is 0.025 W/m*K. Determine the rate of heat loss by air per meter of duct.

air is flowing inside of a pipe with radius=0.4 meters at a mass velocity of 29.4 kg/sm2 at 322 K, with the walls of the pipe at 300 K. At the conditions of the experiment, the viscosity of air is 1.984 x 10-5 Pas, the density of air is 1.22 kg/m3, the heat capacity is 1 kJ/kgK, and the thermal conductivity is 0.025 W/mK. Determine the rate of heat loss by air per meter of duct.

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.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.16P

See similar textbooks

Similar questions

Calculate delta S when 1 mole of supercooled water at –10oC and 100 kPa is converted into ice at -10oC and 100 kPa. The molar heat capacity at constant pressure (Cm,P) of ice is 37.7 J K-1 mol- 1, and that of supercooled water is 76.1 J K-1 mol-1. The enthalpy of freezing of water is -6004 J mol-1. final answer: -20.54 J K-1
What are the Poisson equations? How would the respective equations look like at isothermal, iso-choric, isobaric conditions?
In a gas-fired boiler, water is being boiled at 120°C by hot air flowing through a 5-m-long, 5-cm-diameter tube submerged in water. Hot air enters the tube at 1 atm and 300°C at a mean velocity of 7 m/s and leaves at 150°C. If the surface temperature of the tube is 120°C, determine the average convection heat transfer coefficient of the air and the rate of water evaporation, in kg/h.
One house owner with a pond on his property has decided to use the pond water to cool his house. His idea is to flow air through a thin smooth 10-cm-diameter copper tube that could be submerged into the pond. The water in the pond, at few meters below the surface is typically maintained at a constant temperature of 15°C. If he assumes the air (~1 atm) entering the copper tube at a mean temperature of 30°C with an average velocity of 2.5 m/s, determine the necessary copper tube length that would be needed so that the outlet mean temperature of the air is 20°C. You may consider the convection heat transfer coefficient of 1000 W/m2·K on the outer surface of the copper tube, between the pond water and copper tube. Since the copper tube is thin, the conduction resistance of the tube wall may be neglected.
Hot air at 1 bar and 80 degree Celcius enters a 8 m long uninsulated square duct of cross-section 20 cm x 20 cm that passes through the attic of a house at a rate of 150 L/s. The duct is observed to be constant surface temperature of 60 degrees Celcius. Determine (a) air film coefficient (b) the exit temperature of air (c) logarithmic mean temperature difference (d) the rate of heat loss from the duct to the attic space. From Table A-18, for air gives, density, ρ = 1.009 kg/m^3thermal conductivity, k = 0.0297 W/m degree celciusviscosity, v = 2.06 x 10^-5 m^2/sspecific heat, Cp = 1008 J/kg degree celciusPrandtl no., Pr = 0.706
Steam flowing at a rate of 10 kg/h enters a steam turbine at a velocity of 50 m/s andleaves at a point 5 m below the inlet at a velocity of 300 m/s. The heat loss from the turbine is estimated to be 10 kW, and the turbine delivers shaft work at a rate of 70 kW. Calculate the change in enthalpy transport rate of the process
A 25-cm-diameter stainless steel ball (r = 8055 kg/m3, cp 480 J/kg·°C) is removed from the oven at a uniform temperature of 300°C . The ball is then subjected to the flow of air at 1 atm pressure and 25°C with a velocity of 3 m/s. The surface temperature of the ball eventually drops to 200°C. Determine the average convection heat transfer coefficient during this cooling process and estimate how long the process will take.
Carbon dioxide gas at 3 MPa and 500 K flows steadily in a pipe at a rate of 0.4 kmol/s. Determine (a) the volume and mass flow rates and the density of carbon dioxide at this state.
Air at 20°C and 1 atm flows through a cylindrical tube made of naphthalene at a velocity of 5 m/s. The diameter of the tube is 0.1 m. Using the correlations, calculate the mass transfer coefficient for this setup. Then, compare this result with the mass transfer coefficient from the Reynolds Analogy, Prandtl Analogy, Von Karman Analogy, and Chilton-Colburn Analogy. The effectivity diffusivity is 4.24 x 10-6 m2/s.
Consider an air solar collector that is 1 m wide and 5 m longand has a constant spacing of 3 cm between the glass cover andthe collector plate. Air enters the collector at 30°C at a rate of0.15 m3/s through the 1-m-wide edge and flows along the 5-mlong passage way. If the average temperatures of the glasscover and the collector plate are 20°C and 60°C, respectively,determine (a) the net rate of heat transfer to the air in thecollector and (b) the temperature rise of air as it flows throughthe collector.
Butane gas at 300K and 400 kPa enters a 150-mm steel pipe at a velocity of 60 m/s. Assuming adiabatic friction flow, determine the Fanning friction factor of the flow and the maximum allowable length of the pipe.
What should be the maximum radius of a pipe, to ensure that a liquid with a density of 5 g/cm^3 and a viscosity of 0.00522 kg/m*s, flowing horizontally at a velocity of 60 cm/s in laminar flow through the pipe at a temperature of 4°C?