0.5 W of heat passes from the bottom of a silicon chip (k = 130 W/m-K) and then dissipated to the surroundings by convection. The chip is 6mm x 6 mm x 0.5mm thick. A fan blows air at 20°C into the chip. The forced convection heat transfer coefficient is 250 W/m² K. Disregarding any heat transfer through the o.5mm high side surfacesm determine the following: a. the surface temperature at the top of the chip b. the surface temperature at the bottom of the chip Assume steady state conditions. Silicon chip 0.5 mm 0.5 W -6mm -6 mm Ceramic

0.5 W of heat passes from the bottom of a silicon chip (k = 130 W/m-K) and then dissipated to the surroundings by convection. The chip is 6mm x 6 mm x 0.5mm thick. A fan blows air at 20°C into the chip. The forced convection heat transfer coefficient is 250 W/m² K. Disregarding any heat transfer through the o.5mm high side surfacesm determine the following: a. the surface temperature at the top of the chip b. the surface temperature at the bottom of the chip Assume steady state conditions. Silicon chip 0.5 mm 0.5 W -6mm -6 mm Ceramic

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 6.36P

See similar textbooks

Similar questions

Consider a house that is maintained at a constanttemperature of 22°C. One of the walls of the house has threesingle-pane glass windows that are 1.5 m high and 1.8 mlong. The glass (k = 0.78 W/m·K) is 0.5 cm thick, and theheat transfer coefficient on the inner surface of the glass is8 W/m2·K. Now winds at 35 km/h start to blow parallel to thesurface of this wall. If the air temperature outside is -2°C,determine the rate of heat loss through the windows of thiswall. Assume radiation heat transfer to be negligible. Evaluatethe air properties at a film temperature of 5°C and 1 atm.
Hot air leaving the stove in the kitchen of a house at 70 0C, with a square section of 22 cm x 22 cm.sheet metal enters the 12 m long section of the channel with a speed of 6 m/s. Emissivity 0.3The outer surface of the duct, whose thermal resistance is neglected, is located in the basement of the house at 14 0C and 12 W/m2.It is in contact with cold air with 0C convection heat transfer coefficient. Basementtaking the wall temperatures of the floor to 14 0C.Find the rate of heat loss from the hot air in the duct to the floor.
Air is flowing in parallel over the upper surface of aflat plate with a length of 4 m. The first half of the plate length,from the leading edge, has a constant surface temperatureof 50°C. The second half of the plate length is subjected toa uniform heat flux of 86 W/m2. The air has a free streamvelocity and temperature of 2 m/s and 10°C, respectively.Determine the local convection heat transfer coefficients at1 m and 3 m from the leading edge. Evaluate the air propertiesat a film temperature of 30°C. Is the film temperatureTf = 30°C applicable at x = 3 m?
An average man has abody surface area of 1.8m2 and a skin temperature of 33degrees celcius .The convection heat transfer coefficient for a clothed person walking in still air is expressed as {h,8.6V^0.53}FOR 0.5<v<2m/s,where V is the walking velocityin m/s.Assuming the average surface temperature of the clothed person to be 30degrees celcius, determine the rate of heat loss from an average man walking in still air at 10degrees celcius by convectionat a walking velocity of (a)0.5m/s (b)1.0m/s (c)1.5m/s (d)2.0m/s
Q3: Air flows across a 20-cm-square plate with a velocity of $ m/s. Free-stream conditions are 10-C and 0.2 atm. A heater in the plate surface furnishes a constant heat-flux condition at the wall so that the average wall temperature is 100-C. Calculate the surface heat flux and the value of h at an x position of 10 cm. Answers: Q= 1414 W, b= 13.3 Wm?.C
Air is flowing in parallel over the upper surface of a flat plate with a length of 4 m. The first half of the plate length, from the leading edge, has a constant surface temperature of 50°C. The second half of the plate length is subjected to a uniform heat flux of 86 W/m2. The air has a free stream velocity and temperature of 0.5 m/s and 10°C respectively. The properties of air at Tf = 30°C are k = 0.02588 W/m∙K, ν = 1.608 × 10−5 m2/s, and Pr = 0.7282. Determine the local convection heat transfer coefficients at 1 m and 3 m from the leading edge.
Air is flowing in parallel over the upper surface of a flat plate with a length of 4 m. The first half of the plate length, from the leading edge, has a constant surface temperature of 50°C. The second half of the plate length is subjected to a uniform heat flux of 86 W/m2. The air has a free stream velocity and temperature of 0.5 m/s and 10°C respectively. The properties of air at Tf = 30°C are k = 0.02588 W/m∙K, ν = 1.608 × 10−5 m2/s, and Pr = 0.7282.Determine the local convection heat transfer coefficients at 1 m from the leading edge.
Q6: A large vertical plate 6.1 m high and 1.22 m wide is maintained at s constant temperature of 57:C and exposed to atmospheric air at 4-C. Caleulate the heat lost by the plate. Answers: Q
Explain, motorcycle engine is either considered as free or forced convection. Justify your answer
Air at 300°C flows over a flat plate of dimensions 0.50m by 0.25m. If theconvection heat transfer coefficient is 250 W/m2K, determine the heat transferrate from air to one side of the plate when the plate is maintained at 40°C.(ans.8.125 KW)
A heating system is to be designed to keep the wings of an aircraft cruising at a velocity of 900 km/h above freezing temperatures during flight at 12,200-m altitude where the standard atmospheric conditions are 55.4°C and 18.8 kPa. Approximating the wing as a cylinder the elliptical cross section whose minor axis is 30 cm and disregarding radiation, determine the average convection heat transfer coefficient on the wing surface and the average rate of heat transfer per unit surface area.
Consider a 1.2-m-high and 2-m-wide glass windowwith a thickness of 6 mm, thermal conductivity k = 0.78W/m·K, and emissivity « = 0.9. The room and the wallsthat face the window are maintained at 25°C, and the averagetemperature of the inner surface of the window is measuredto be 5°C. If the temperature of the outdoors is 25°C,determine (a) the convection heat transfer coefficient on theinner surface of the window, (b) the rate of total heat transferthrough the window, and (c) the combined natural convectionand radiation heat transfer coefficient on the outer surface ofthe window. Is it reasonable to neglect the thermal resistanceof the glass in this case?