A hot surface at 100°C is to be cooled by attaching 3-cm-long, 0.25-cm-diameter copper pin fins (k = 386 W /m · °C) to it, with a center-to-center distance of 0.6 cm. The temperature of the surrounding medium is 30°C, and the heat transfer coefficient on the surfaces is 35 W /m² . °C. Determine the rate of heat transfer from %3D the surface for a 1m x 1m section of the plate. Also determine the overall effectiveness of the fins. 3 cm D=0.25 cm 0.6 cm

A hot surface at 100°C is to be cooled by attaching 3-cm-long, 0.25-cm-diameter copper pin fins (k = 386 W /m · °C) to it, with a center-to-center distance of 0.6 cm. The temperature of the surrounding medium is 30°C, and the heat transfer coefficient on the surfaces is 35 W /m² . °C. Determine the rate of heat transfer from %3D the surface for a 1m x 1m section of the plate. Also determine the overall effectiveness of the fins. 3 cm D=0.25 cm 0.6 cm

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.19P: 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the...

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1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
A wall with a thermal conductivity of 0.4 W/m-°C is maintained at 45°C. The heat transfer through the wall is 220 W. The wall surface area is 2.0m² and its thickness is 1.5 cm. Determine the temperature at the other surface.
H.W. Q:A hot surface at 100°C is to be cooled by attach- ing 3-cm-long, 0.25-cm-diameter aluminum pin fins (k 237 W/m - °C) to it, with a center-to-center distançe of 0.6 cm. The temperature of the surrounding medium is 30°C, and the heat transfer coefficient on the surfaces is 35 W/m2 · °C. Determine the rate of heat transfer from the surface for a 1-m x 1-m section of the plate. Also determine the overall effectiveners of the fins. Ans. Q=17.4 kW , E fin = 7.1 3 сm 0.6 cm 0.25 cm
Q2: A hot surface at 150°C is to be cooled by attaching 4- cm-long, 0.3-cm-diameter aluminum pin fins (k = 200 W/m • °C) to it, with a center- to-center distance of 1 cm. The temperature of the surrounding medium is 25°C, and the heat transfer coefficient on the surfaces is 40 W/m2.°C. Determine the rate of heat transfer from the surface for a 2m * 2m section of the plate. Also determine the overall effectiveness of * .the fins
1-88 Consider a 20-cm-thick granite wall with a thermal con- ductivity of 2.79 W/m-K. The temperature of the left surface is held constant at 50°C, whereas the right face is exposed to a flow of 22°C air with a convection heat transfer coefficient of 15 W/m?-K. Neglecting heat transfer by radiation, find the right wall surface temperature and the heat flux through the wall. Granite :k= 2.8 W/m-K T = 22°C T = 50°C h = 15 W/m²-K 20 cm
A rectangular wall of length "L" m and height "H" m is made from a thick bricklayer. The rectangular wall has a surface area as 11 m2 & Thermal conductivity as 0.53 W/mK. The wall is subjected to heat transfer due to the outside temperature 43 °C and inside temperature 24 °C. If the energy loss is 11219 kJ in 484 minutes. (HINT: 1 minute = 60 %3D seconds) Determine the following -- i) Heat transfer rate, ii) Thickness of the wall.
For heat transfer purposes, a standing man can be modeled as a 30-cm-diameter, 170-cm-long vertical cylinder with both top and bottom surfaces insulated and with the side surface at an average temperature of 34 °C. For a convection heat transfer coefficient of 15 W/m2∙°C, determine the rate of heat loss from this man by convection in an environment at 20 °C. Round your answer to 2 decimal places.
To warm up some milk in a thin-walled glass cylindrical container whose diameter is 6 cm. The height of the milk in the glass is 7 cm. The milk container is placed into a large pan filled with hot water at 60°C. The milk is stirred constantly, so that its temperature is uniform at all times. If the heat transfer coefficient between the water and the glass is 120 W/m2.°C, determine how long it will take for the milk to warm up from 3°C to 38°C. Take the properties of the milk to be the same as those of water. Can the milk in this case be treated as a lumped system? Use the lumped system analysis to solve the problem. The properties of water and milk at 20°C are, k = 0.607 W/m.°C,p=998 kg/m', and C, = 4.182 kJ/kg.°C. Answer: 5.8 min. ملاحظه: تكون هنا قيمة (0.1 < Bi( ويفترض لايطبق التحليل الكتلي , ولكن استخدم نفس التحليل والمعادلات في المحاضرة وكذلك في المثال لان الحليب يخلط باستمرار ولذلك تكون درجة حرارته منتظمه و متغيره مع الزمن لانه يكتسب حراره من الماء ويسخن وترتفع درجة حرارته مع…
The brick wall of a house measures 4 x 7 m and has a thickness of 0.3 m. The thermal conductivity of the brick is 0.69 W/m.K. If the inner and outer temperatures of the wall are 26oC and 8oC respectively, determine the rate of heat transfer through the wall.
Q:A hot surface at 100°C is to be cooled by attach- ing 3-cm-long, 0.25-cm-diameter aluminum pin fins (k 237 W/m · °C) to it, with a center-to-center distançe of 0.6 cm. The temperature of the surrounding medium is 30°C, and the heat transfer coefficient on the surfaces is 35 W/m2 . °C. Determine the rate of heat transfer from the surface for a 1-m X 1-m section of the plate. Also determine the overall effectiveners of the fins. Ans. Q=17.4 kW , E fin = 7.1 3 cm 0.6 cm L0.25 cm
The inner and outer surfaces of a cylindrical shell with radii of 1 cm and 2 cm are 300 °C and 100 °C, respectively. If the thermal conductivity of the shell is 2 W/m-K, determine the heat transfer through the shell per unit length of the cylinder.
Q2/ The inner and outer surfaces of a 0.5-cm- thick 2-m x2-m window glass in winter are 10°C and 3°C, respectively. If the thermal conductivity of the glass is 0.78 W/m - °C, determine the amount of heat loss, in kJ, through the glass over a period of 5 hours. What would your answer be if the glass were I cm thick? Answers: 78,624 kJ, 39,312 kJ.