13.22 A tubular heater with a black inner surface of uniform temperature T₁ = 1000 K irradiates a coaxial disk. D₂ = 100 mm -Insulation -Heater surface, T, -Disk D₂ = 50 mm -L₂ = 100 mm -L₁ = 100 mm- (a) Determine the radiant power from the heater, which is incident on the disk, 91- What is the irradiation on the disk, G₁? (b) For disk diameters of D₁ = 25, 50, and 100 mm, plot q and G₁ as a function of the separation distance L, for 0 ≤ L₁ ≤ 200 mm.

13.22 A tubular heater with a black inner surface of uniform temperature T₁ = 1000 K irradiates a coaxial disk. D₂ = 100 mm -Insulation -Heater surface, T, -Disk D₂ = 50 mm -L₂ = 100 mm -L₁ = 100 mm- (a) Determine the radiant power from the heater, which is incident on the disk, 91- What is the irradiation on the disk, G₁? (b) For disk diameters of D₁ = 25, 50, and 100 mm, plot q and G₁ as a function of the separation distance L, for 0 ≤ L₁ ≤ 200 mm.

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.

Chapter11: Heat Transfer By Radiation

Section: Chapter Questions

Problem 11.30P

See similar textbooks

Similar questions

1.26 Repeat Problem 1.25 but assume that the surface of the storage vessel has an absorbance (equal to the emittance) of 0.1. Then determine the rate of evaporation of the liquid oxygen in kilograms per second and pounds per hour, assuming that convection can be neglected. The heat of vaporization of oxygen at –183°C is .
13.22 A tubular heater with a black inner surface of uniform temperature T, = 1000 K irradiates a coaxial disk. – Insulation Disk Heater surface, T, D2 = 100 mm D = 50 mm -L2 = 100 mm L, = 100 mm (a) Determine the radiant power from the heater, which is incident on the disk, q,→1- What is the irradiation on the disk, G,? |(b) For disk diameters of D, = 25, 50, and 100 mm, plot q,--1 and G, as a function of the separation distance L, for 0
13.18 A drying oven consists of a long semicircular duct of diameter D = 1 m. T = 1200 K - T2 = 325 K D = 1 m Materials to be dried cover the base of the oven while the wall is maintained at 1200 K. What is the drying rate per unit length of the oven (kg/s ·m) if a water- coated layer of material is maintained at 325 K during the drying process? Blackbody behavior may be assumed for the water surface and the oven wall.
**33. ssm A solid cylinder is radiating power. It has a length that is ten times its radius. It is cut into a number of smaller cylinders, each of which has the same length. Each small cylinder has the same temperature as the original cylinder. The total radiant power emitted by the pieces is twice that emitted by the original cylinder. How many smaller cylinders are there?
34.) A duct, consisted of four rectangular flat plates, are radiating with each otherand nothing else. Use the given data to find the radiosity and the rate of heattransfer for each surface. Data: Length = 1 m, depth, 2 m, height 0.5 m, T1 = 100C, T2 = 200 C, T3 = 300 C, T4 = 400 C, ε1 = 0.5, ε2 = 0.65, ε3 = 0.75, ε4 = 0.8. Thejoins are well insulated so that there is no heat transfer between the plates bythermal conduction.
13.26 A furnace is constructed in three sections, which include insulated circular (2) and cylindrical (3) sections, as well as an intermediate cylindrical section (1) with imbedded electrical resistance heaters. The overall length and diameter are 200 mm and 100 mm, respec- tively, and the cylindrical sections are of equal length. The surroundings are at 0 K. - A2 (a) If all the surfaces are black, determine the elec- trical power, q1, required to maintain the heated section at 1000 K. (b) What are the temperatures of the insulated sec- tions, T, and T,? |(c) For D = 100 mm, generate a plot of q, T, and T; as functions of the length-to-diameter ratio, with 1s L/D< 5.
! Required information Irradiation on a semi-transparent medium is at a rate of 640 W/m². If 160 W/m² of the irradiation is reflected from the medium and 130 W/m² is transmitted through the medium, Determine the absorptivity of the medium. The absorptivity of the medium is 0.75 X
13.19 Consider the arrangement of the three black surfaces shown, where A, is small compared to A₂ or A3. A₂ 2 m Į -A3 3 m Determine the value of F13. Calculate the net radiation heat transfer from A, to A3 if A₁ = 0.05 m², T₁ = 1000 K, and T3 = 500 K.
4. The surface temperature of a planet is T, and the measured temperature is Tm (i.e. the temper- ature measured at the top-of-atmosphere based on the upwards flux Ft there). Assume radiative equilibrium. (a) Show that the infrared optical depth of the planet's surface 7 is related to the surface temperature T, and the measured temperature Tm by Calculate the infrared optical depth at the surfaces of (a) Earth, where T, = 300 K and Tm = 250 K. (b) Venus, where T, = 750 K and Tm = 230 K. (c) Mars, where T, = 240 K and T, = 220 K.
11.19 A long rod, with a diameter of 3 mm, is placed in a vacuum parallel to a large and flat heated surface. The other side of the rod is exposed to vacuum chamber walls at 300 K. Assume that the heated surface and the surface of the rod are both gray with equal emissivities of 0.7. The rod has a volumetric heat capacity of pc, = 6.7 × 106J m‍³ K¨¹. Calculate the heating rate of the rod at 335 K, 500 K, 700 K, and 800 K. Rod Heated surface at 830 K
13.58 The end of a cylindrical liquid cryogenic propellant tank in free space is to be protected from external (solar) radi- ation by placing a thin metallic shield in front of the tank. Assume the view factor F, between the tank and the shield is unity; all surfaces are diffuse and gray, and the surroundings are at 0 K. T Shield, T, T, = 100 K E1 = E2 = 0.05 &= 0.10 Ĝ3 = 1250 W/m? Tank Solar irradiation Gs Find the temperature of the shield T, and the heat flux (W/m) to the end of the tank.
13.21 Consider coaxial, parallel, black disks separated a dis- tance of 0.20 m. The lower disk of diameter 0.40 m is maintained at 500 K and the surroundings are at 300 K. What temperature will the upper disk of diame- ter 0.20 m achieve if electrical power of 17.5 W is supplied to the heater on the back side of the disk? -Нeater jo.20 m- 0.20 m 500 K- 0.40 m-