A shield having an emissivity of 0.1 is placed around the thermometer in Example 8.12 such that the area ratio A/A, is 0.3. The temperature indicated by the thermometer under these conditions is 5°C. The convection heat- transfer coefficient is assumed to be the same, and the shield may be assumed essentiallv to surround the thermometer. Calculate the true air temperature under these circumstances. And IMPROVEMENT WITH RADIATION SHIELD. un e, = 0.1, € = 0.9, h = 10 W/m2- °C A 0.3, T, = 273 +5 = 278 K, T, = 263 K %3D %3D -

A shield having an emissivity of 0.1 is placed around the thermometer in Example 8.12 such that the area ratio A/A, is 0.3. The temperature indicated by the thermometer under these conditions is 5°C. The convection heat- transfer coefficient is assumed to be the same, and the shield may be assumed essentiallv to surround the thermometer. Calculate the true air temperature under these circumstances. And IMPROVEMENT WITH RADIATION SHIELD. un e, = 0.1, € = 0.9, h = 10 W/m2- °C A 0.3, T, = 273 +5 = 278 K, T, = 263 K %3D %3D -

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 7.48P

See similar textbooks

Related questions

Q: After sunset, radiant energy can be sensed by a person standing near a brick wall. Such walls…

A: The radiant thermal flux per square metre from a brick wall at this temperature: 526.75 W/m2

Q: Explain, with annotated diagrams, the different effects of insulation and thermal mass on the heat…

A: A case study of Al Mafraq city in Jordan can be used to understand the varying impacts of insulation…

Q: Calculate the equilibrium temperature of the plate, based on the incoming solar radiation and the…

A: DefinitionThermal radiation:This topic investigates how electromagnetic waves transmit heat across…

Q: Show that if the atmosphere is isothermal, the temperature change of a parcel of air rising…

Q: A horizontal steam pipe with an outside diameter of 60.0 mm passes through a large room whose walls…

Q: T. = 310 K The thickness of a wall is 0.07 m. right side of the wall air and T sur = 300 K exposed…

A: given data; ⇒thickness of wall (x)=0.07m⇒external surface temperature of wall right side…

Q: A vertical, double-pane window(square), which is 1 m on a side and has a 25-mm gap filled with…

Q: A long pipe 5 cm in diameter passes through a room and is exposed to air at atmospheric pressure and…

Q: A limited amount of water in a container is subjected to 5 W/m²K convection condition as the sky…

A: Heat transfer coefficient (h) = 5 W/m2kSky temperature = -40oCEmissivity Freezing temperature of…

Q: A circular plate of diameter (2.07 m) is placed some how 1.5 meter above the room floor, if the…

A: Given data as: Diameter of the plate (D)=2.07 m Height of the plate from ground (H)=1.5 m Raleigh…

Q: Q1/ consider a (0.8m) high and (1.5m) wide double pane widow consisting of two (4mm) thick layers of…

A: As given that the area normal to heat transfer will be A=0.8×1.5 m2 ;⇒A = 1.2 m2 ;So the thermal…

Q: A solar collector consists of a long duct through side consists of a glass cover of emissivity &₁ =…

Q: ce is facin an air having temperature of 30°C, then what will be th value of coefficient of…

Q: Chips of width L _ 15 mm on a side are mounted to a substrate that is installed in an enclosure…

A: GivenTs=85+273=358 kTsur=T∞=298 ka) h=11.7 W/m2Kb) h=250W/m2KL=15 mmε=0.60

Q: Question 2 A thermometer having an emissivity of 0.9 is placed in a large room and indicates a…

Q: We wish to use the analytical model developed by Joshi and Webb to predict the heat transfer and…

A: Given data;It is asked to use the analytical model developed by Joshi and Web to predict the heat…

Q: An overhead 65-m-long, uninsulated industrial steam pipe of 80 mm diameter is routed through a…

A: Given DataTs=200°CT∞=30°Ch=15W/m2Kε=0.6L=65mD=80mm

Q: Temperature is commonly measured with gas-in-glass thermometers, wherein the gas expands when…

Q: A silicon wafer of diameter D120 mm, and emissivity of 0.6 is at an initial temperature of Ti 325oC…

Q: 2. A steam line is covered with two successive layers of insulation. The 1.6 in thick layer in…

Question

IMPROVEMENT WITH RADIATION SHIELD.
A shield having an emissivity of 0.1
Example 8.13
is placed around the thermometer in Example 8.12 such that the area ratio A/A, is 0.3. The
temperature indicated by the thermometer under these conditions is 5°C. The convection heat-
transfer coefficient is assumed to be the same, and the shield may be assumed essentially to
surround the thermometer. Calculate the true air temperature under these circumstances. And estimate its
uncertainty
E, = 0.1,
A
= 0.3,
A,
€ = 0.9,
h = 10 W/m2 - °C
T, = 273 +5 = 278 K,
T, = 263 K

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

This is a popular solution!

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Trending now

This is a popular solution!

Step by step

Solved in 2 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.

Similar questions

A mercury-in-glass thermometer at 40C(OD=1cm) is inserted through a duct wall into a 3 m/s airstream at 66C. This can be modelled as a cylinder in cross-flow, as shown in the figure. Estimate the heat transfer coefficient between the air and the thermometer.
IMPROVEMENT WITH RADIATION SHIELD. A shield having an emissivity of 0.1 Example 8.13 is placed around the thermometer in Example 8.12 such that the area ratio A/A, is 0.3. The temperature indicated by the thermometer under these conditions is 5°C. The convection heat- transfer coefficient is assumed to be the same, and the shield may be assumed essentiallv to surround the thermometer. Calculate the true air temperature under these circumstances. And find estimate its uncertainty? h = 10 W/m - °C E, = 0.1, A = 0.3, A, E = 0.9, T, = 273 +5 = 278 K, T, = 263 K
Write the appropriate Nusselt value for the each set of conditions provided below.1. Forced convection over a flat plate at constant qs. Calculated Re at mean temperature is 3500 and Pr= 0.7154. 2. Natural convection in a small holding tank with a heating element at the bottom. The calculated Ra number is 2.37 x10^93. Forced convection through an elliptical duct at constant Ts, where a/b=8. The temperature of the fluid at the inlet is higher than at the exit. Flow is fully developed with Re = 33370 and Pr= 0.693. 4. Natural convection over a sphere with Ra = 5 x 10^9 and Pr = 0.7362 PS. Do not round off intermediate values
Q1/ consider a (0.8m) high and (1.5m) wide double pane widow consisting of two (4mm) thick layers of glass (k=0.78W/m.°C) separated by a (10mm) wide stagnant air space (k=0.026W/m.C). ). Take the (hi) on the inner surface = 10W/m2.°C and (ho) on the outer surface = 40W/ m².°C. Determine The steady rate of heat transfer through this double pane window is equal The temperature of its inner surface for a day during which the room is maintained at (293K) while the temperature of the outdoor is (263K) is equal to *
A camera used for monitoring marine life is placed in water where T.. -5°C and the convection heat transfer coefficient h=1420 W/m²K. The camera is operating, but its battery is experiencing thermal runaway, causing the camera to become very hot, and there is volumetric heat generation, qe inside it. There is no heat generation within the waterproof, protective enclosure surrounding it. 00:08 The camera is already compromised; however, its owner hopes to save the protective case. Each interface (between layers A and B and between layers B and C) must not exceed a temperature of 185°C, or these plastic, protective layers will begin to melt. Approximate the camera and its casing as a composite, rectangular object with flat surfaces. The device's total thickness, L=LA + 2LB +Lc, is much smaller than its area (into the page); therefore, 1-D conduction can be approximated through the layers. On the left surface of layer A, the temperature is measured to be T₁ = 8.0°C, and the temperature on…
A chromel–constantan thermocouple measuring the temperature of a fluid is connected by mistake with copper–constantan extension leads (such that the two constantan wires are connected together and the copper extension lead wire is connected to the chromel thermocouple wire). If the fluid temperature was actually 250 C and the junction between the thermocouple and extension leads was at 90 C, what e.m.f. would be measured at the open ends of the extension leads if the reference junction is maintained at 0 C? What fluid temperature would be deduced from this (assuming that the connection error was not known)?
A composite plane wall consisting of materials, 1.5-in steel (k = 312 BTU-in/HR.ft2.0F) and 2-in aluminum (k = 1400 BTU-in/HR.ft2.0F), separates a hot gas at Ti = 2000F, hi = 2 BTU/HR.ft2.0F, from cold gas at To = 80 deg F, ho = 5. If the hot fluid is on the aluminum side, find: a) Transmittance, U; b) The heat through 100 sq. ft of the surface under steady state condition and c) The interface temperature at the junction of the metals.
1. A composite furnace wall is made up of a 12-in. lining of magnesite refractory brick, a 5-in.thickness of 85% magnesia, and a steel casing 0.10-in. thick. Flue gas temperature is 2200 F andthe boiler room is at 80 F. Gas side film coefficient is 15 Btu/hr-sq.ft-F and air side is 4.0.Determine:a. The thermal current Q/Ab. Interface temperaturesc. Effect on thermal current and inside refractory wall temperature if the magnesia insulation weredoubled.
a. What units must the constant 0.644 have?b. What should be the value of the constant when all units areconverted to English units (masses in lbm, lengths in ft, temperatures in oR,times in h, energies in Btu)? answer asap please
The interior of a refrigerator whose dimensions are 0.05 x 0.05 dam base area and 1.25 m high, must be kept at 4 °C. The refrigerator walls are constructed of two steel sheets (k= 35 kcal/h.m.°C) 3 mm thick, with 65 mm of material insulation (k=0.213 kcal/h.m.°C) between them. The film coefficient of the inner surface is 10 kcal/h.m².°C, while on the external surface it varies from 8 to 12.5 kcal/h.m².°C. Calculate: a) The power (in HP) of the refrigerator motor so that the heat flux removed from the inside the refrigerator maintain the specified temperature, in a kitchen whose temperature can vary from 21 to 36 °C; b) The temperatures of the inner and outer surfaces of the wall. Given 1 HP = 641.2 Kcal/h
Chips of width L _ 15 mm on a side are mounted to a substrate that is installed in an enclosurewhose walls and air are maintained at a temperature of Tsur=T∞=25oC. The chips have an emissivity ofε=0.60 and a maximum allowable temperature of Ts=85oC.(a) If heat is rejected from the chips by radiation and natural convection, what is the maximum operatingpower of each chip? The convection coefficient may be approximated as h=11.7 W/m2K.(b) If a fan is used to maintain airflow through the enclosure and heat transfer is by only forcedconvection, with h=250 W/m2K, what is the maximum operating power?
Determine the optimum thickness from an economic point of view, of insulation for a steam pipe 100 mm dia. at 465°C. The insulation conductivity is 1.55 x 10 kW/mK, the natural convection coefficient -4 on the insulation outer surface is 0.0112 kW/m2K, the insulation cost is £70/m³ plus a fixed charge of 160p. per metre run of pipe and the cost is to be spread over 5 veres. The oil fuel, of density 900 kg/m³, costs 1.lp. per litre and is used to raise steam in a boiler of 90% efficiency. The fuel calorific value is 41,000 kJ/Kg and the air temperature surrounding the insulation is 27°c.