An uninsulated steam pipe of 100-mm diameter is routed through a building whose walls and air are at 27°C. Pressurized steam maintains a pipe surface temperature of 147°C, and the coefficient associated with natural convection is h =10 W/m2.K. The surface emissivity is ɛ= 0.8. What is the rate of heat loss per unit length from the steam line?

An uninsulated steam pipe of 100-mm diameter is routed through a building whose walls and air are at 27°C. Pressurized steam maintains a pipe surface temperature of 147°C, and the coefficient associated with natural convection is h =10 W/m2.K. The surface emissivity is ɛ= 0.8. What is the rate of heat loss per unit length from the steam line?

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.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.4P: An electrical transmission line of 1.2-cm diameter carries a current of 200 amps and has a...

See similar textbooks

Similar questions

An electrical transmission line of 1.2-cm diameter carries a current of 200 amps and has a resistance of 310-4 ohm per meter of length. If the air around this line is at v, determine the surface temperature on a windy day, assuming a wind blows across the line at 33 km/h.
3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
Thermodynamics problem. A membrane type electrical heater of 20,000 w/m? capacity is sandwiched between an Insulation of 25 mm thickness with thermal conductivity of 0.029 W/m-K and a metal plate with k = 12.6 W/m-K of thickness 15 mm. The convection coefficient is 150 W/m2-K. The surroundings are at 5°C. Determine the surface temperature of the heater and the flow on either side.
A food product with 73% moisture content in a 5 cm diameter can wants to be frozen. The density of the product is 970 kg / m³, the thermal conductivity is 1.2 W / (m K), and the initial freezing temperature is -2 ° C. After 12 hours in the freezing medium -30 ° C, the product temperature becomes -10 ° C. Estimate the convection heat transfer coefficient of the freezing medium. Assume the can as an infinite cylinder. h = W / (m² K).
A food product with 73% moisture content in a 5 cm diameter can wants to be frozen. The density of the product is 970 kg / m³, the thermal conductivity is 1.2 W / (m K), and the initial freezing temperature is -2 ° C. After 12 hours in the freezing medium -30 ° C, the product temperature becomes -10 ° C. Estimate the convection heat transfer coefficient of the freezing medium. Assume the can as an infinite cylinder. h = AnswerW / (m² K).
Required information Air flows in a pipe under fully developed conditions with an average velocity of 1.25 m/s and a temperature of 24°C. The pipe's inner diameter is 4 cm, and its length is 4 m. The first half of the pipe is kept at a constant wall temperature of 100°C. The second half of the pipe is subjected to a constant heat flux of 200 W. The properties of air at 80°C are p = 0.9994 kg/m³, k = 0.02953 W/m-K, v= 2.097 x 10-5 m²/s, cp=1008 J/kg-K, and Pr = 0.7154. NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Air 1.25 m/s 2m T, = 100°C D = 4 cm 2 m g, = 200 W Determine the wall temperature at the exit of the tube. The wall temperature at the exit of the tube is 282 * °C.
Required information Water at 20°C is flowing with velocity of 0.89 m/s between two parallel flat plates placed 1 cm apart. Given: The ploperties of water at 20°C are p= 998.0 kg/m3, µ = 1.002 × 103 kg/m-s and Pr = 7.01 Determine/the distances from the entrance at which the thermal boundary layers meet. (Round the final answer to one decimal place.) The distance from the entrance at which the velocity boundary layers meet is m.
Air at 40C flows over a long, 25-mm-diameter cylinder with an embedded electric heater. In a series of tests, measurements were made of the power per unit length, P’, required to maintain the cylinder surface temperature at 300C for different free stream velocities V of the air. The results are as follows: Determine the convection coefficient in W/(m2K) for each velocity.
A food product with 73% moisture content in a 10 cm diameter can wants to be frozen. The density of the product is 970 kg / m³, the thermal conductivity is 1.2 W / (m K), and the initial freezing temperature is -1.75 ° C. After 15 hours in the freezing medium -25 ° C, the product temperature becomes -10 ° C. Estimate the convection heat transfer coefficient of the freezing medium. Assume the can as an infinite cylinder. h = Answer W / (m² K).
Compute the Nu numbers for air at 40°C flowing with 4 m/s speed over the following: 1) A Copper sphere of 5 cm in diameter with 80°C isothermal surface temperature 2) A circular Aluminum pipe of 6 cm in diameter with 80°C isothermal surface temperature 3) A bank of 20x20 5-mm diameter tubes arranged in-line with center-to-center distance of 20 mm. Each tube is assumed to have isothermal temperature of 80°C. Please show detailed calculations.
Electric current of 150 A is carried through a 5 mm diameter cylindrical wire which has a resistance of 0.003 ohm per meter length. The wire is exposed to a cross flow of air at 22°C and its surface temperature is measured as 30°C. In your calculations, take air properties at 300 K and use the following correlation and constants: Rep C m 0.4-4 0.989 0.330 hD Nup = k 4-40 0.911 0.385 C Re, PH %3D %3D 40–4000 0.683 0.466 4000 – 40,000 0.193 0.618 40,000– 400,000 0.027 0.805 Calculate the average heat transfer coefficient in W/m2K Calculate the air velocity in m/s
Thermal jackets are typically put on cryogenicstorage tanks to minimize the heat transfer gainsfrom the surroundings. Consider a cylindercontainer that is 1.5 m long made from steel (k = 750W/m.K) with an inner diameter of 0.5 m and outerdiameter of 0.7 m. If the liquefied natural gas (LNG)inside the cylinder is maintained at 90 K, ambientconditions are Tamb = 20 °C, h = 7 W/m2.K. What is the required insulationmaterial to maintain the outer temperature of that jacket of 15 °C? Usethe end of the book and write your assumption with the right value.(Take a maximum allowed jacket thickness of Lins = 7 cm)