Natural Convection Cooling of an Orange.An orange 102 mm in diameter having a surface temperature of 21.1°C is placed on an open shelf in a refrigerator held at4.4°C. Calculate the heat loss by natural convection, neglecting radiation. As an approximation, the simplified equation for vertical planes can be used withLreplaced by the radius of the sphere (M1). For a more accurate correlation, see (S2

Natural Convection Cooling of an Orange.An orange 102 mm in diameter having a surface temperature of 21.1°C is placed on an open shelf in a refrigerator held at4.4°C. Calculate the heat loss by natural convection, neglecting radiation. As an approximation, the simplified equation for vertical planes can be used withLreplaced by the radius of the sphere (M1). For a more accurate correlation, see (S2

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.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.13P

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A spherical communications satellite, 2 m in diameter, is placed in orbit around the earth. The satellite generates 1000 W of internal power from a small nuclear generator. If the surface of the satellite has an emittance of 0.3, and is shaded from solar radiation by the earth, estimate its surface temperature.
A spherical interplanetary probe of 0.5-m diameter contains electronics that dissipate 150 W. If the probe surface has an emissivity of 0.8 and the probe does not receive radiation from other surfaces, as, for example, from the sun, what is its surface temperature?
I REALLY NEED THE ANSWER UNTIL 5:20PM PLEASE A vertical cylindrical container is being cooled in ambient air at 25°C with no air circulation.If the initial temperature of the container surface is 100°C, compute the surfaceheat transfer coefficient due to natural convection during the initial cooling period. Thediameter of the container is 1 m, and it is 2m high. HELP ME IF MY SOLUTION IS CORRECT, I THINK THIS IS NOT COMPLETE YET. KINDLY HELP ME PLEASE
A cylinder 6”in diameter and 18”long is suspended horizontally in a largeroom. The air and wall surfaces of the room are at a temperature of 60 °Fwhile the surface temperature of the cylinder is 440 °F. Compute (a) thesurface coefficient due to free convection, (b) the heat transferred by freeconvection (neglecting the end areas), (c) the surface coefficient due toradiation if the surface emissivity is 0.75, and (d) the total heattransferred by free convection and radiation (neglecting end areas)
A house located in the south of the country was built using windowsdoubles to reduce heat loss to the outside environment on very cold days. Consider that the house has 6 windows 80 cm high and 1.2 m wide, each consisting of 2 layers of glass (kv=1.4 W/(m.oC) 4 mm thick, separated from each other for a spacing of 10 mm filled with stagnant air (ka=0.024 W/(mK), we disregard natural convection effects) On a day when the interior of the house is kept at 22oC, with h=10 W/(m2. K) while the external environment is at 5oC with h=50 W/(m2.K), it is requested:(a) What is the rate of heat dissipation through the windows?(b) What are the temperatures on the glass surfaces inside and in theexterior of the house?(c) Which of the resistances is the limiting in the dissipation process ofheat?(d) Estimate the increase in dissipation rate if we consider that the natural air convection in the space between the windows is characterizedby a convective coefficient h=5 W/(m.K).(e) How the value obtained…
in a certain instance, a blossom get a touvhed of frost on the strawberry, the harvest was significantly reduced. consider a very clear night with a slight breeze of about 10 km/hr making the convection coefficient equal to 21 W/m-k. the outer space temperature maybe assumed to be 110K and the emissivity of the strawberry is 0.70. at what surrounding temperature will the strawberries freeze?
A geodesic dome constructed with an aluminum frameworkis a nearly perfect hemisphere; its diameter measures 55.0 m on a winterday at a temperature of -15°C. How much more interior space does thedome have in the summer, when the temperature is 35°C?
The rear window of an automobile is defogged by passing warm air over its inner surface. If the warm air is at T∞,i=40°C and the corresponding convection coefficient is hi=30 W/m2·K, what are the inner and outer surface temperatures, in °C, of 4-mm-thick window glass, if the outside ambient air temperature is T∞,o= -27.5°C and the associated convection coefficient is ho=65 W/m2·K? Evaluate the properties of the glass at 300 K. a. what is Ts, i in °C? b. what is Ts, o in °C?
The rear window of an automobile is defogged by passing warm air over its inner surface. If the warm air is at T∞,i=40°C and the corresponding convection coefficient is hi=30 W/m2·K, what are the inner and outer surface temperatures, in °C, of 4-mm-thick window glass, if the outside ambient air temperature is T∞,o= -27.5°C and the associated convection coefficient is ho=65 W/m2·K? Evaluate the properties of the glass at 300 K. a. what is the heat flux through the original walls in W/ m^2? b. what is the heat flux through the retrofitted walls in w /m^2?
Calculate the free convection heat transfer coefficient for a plate 6 ft high and 8 ft wide at 120 °F that is exposed to nitrogen at 60 °F. (see attached)
Experiment No. (5) Heat Transfer, Power Input and Surface temperature Questions and Discussions 1. What is the difference between natural and forced convection heat transfer? 2. What sources of error are there in this experiment? 3. Mention the parameters you utilized during the calculation and discuss them briefly. 4. In what functions does Nusselt number in natural convection differ from forced convection, Discuss. 5. Give two examples of natural convection heat transfer. 6. In natural convetion, what makes the hot part of fluid to move?
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?