Consider two aluminum (k=180 W/mK) pin-fin heat sinks with 1 mm and 2 mm square pins both 25 mm long. Assume that the gap between the pins = side of the pin, ie the one mm pin-fin heat sink has 1 mm gap between its pins. Assuming the module base is 50 mm x 50 mm and the heat sink cannot overhang due to lack of space, and h = 40 W/m?K with jet impingement, calculate: (a) Cooling surface area ratio (1 mm heat sink/ 2 mm heat sink) (b) Heat transfer ratio (1 mm heat sink/2 mm heat sink) Try to fit the maximum number of pins on the 50 mm x 50 mm base

Consider two aluminum (k=180 W/mK) pin-fin heat sinks with 1 mm and 2 mm square pins both 25 mm long. Assume that the gap between the pins = side of the pin, ie the one mm pin-fin heat sink has 1 mm gap between its pins. Assuming the module base is 50 mm x 50 mm and the heat sink cannot overhang due to lack of space, and h = 40 W/m?K with jet impingement, calculate: (a) Cooling surface area ratio (1 mm heat sink/ 2 mm heat sink) (b) Heat transfer ratio (1 mm heat sink/2 mm heat sink) Try to fit the maximum number of pins on the 50 mm x 50 mm base

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 1.68P

See similar textbooks

Similar questions

3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
How long must a 0.4 cm cylindrical copper fin be if the temperature of its insulated tip exceeds thesurrounding air temperature by 20% of T0 – T∞? Consider air temp to be 20°C and ℎ̅ = 28 W/m2K. Book gives answerof 27.3 cm.• You can use figure 4.9a or equation 4.45 in the book to find the right mL for the desired  at the tip. • Recall the nondimensional temperature is  = (T – T∞)/(T0 – T∞)
8--The reactor from uniform carbide and graphite as a cylinder rod with diameter of 12 mm. The volumetric heat liberationis 3.88x108 W/m3 The thermal conductivity of the rod material is 85 W/mC.. Determine the heat losses from the rod and the surface temperature if the maximum temperature of the rod is 200C...Ans Tw=1940 C,,Heat losses=1.164 MW/m2.
H.W.5 A wall having a thickness of (4cm) has an internal heat generation of (280MW/m') and a thermal conductivity of (15 W/m.C). One side of the plate is insulated and the other side exposed to air at (30C) and heat transfer coefficient of (10W/m².C). Start from the principle to determine the maximum temperature in the plate and draw the temperature profile inside the wall.
c) A steel pipe of 100 mm bore, and 10 mm bore thickness, carrying dry saturated steam at 28 bars, is insulated with a 40 mm layer of moulded insulation. This insulation in turn is insulated with a 60 mm layer of felt. The atmospheric temperature is 15 °C. Calculate: (i) the rate of heat loss by the steam per metre pipe length. (ii) the temperature of the outside Dimensions in mm surface.zzzzzzz h₂-15 W/m²K Steel k₁=50 W/mK AVALEHT Ø100 1₂ " Steam 28 bar h-550 W/m²K, Inner heat transfer coefficient = 550 W/m² K Outer heat transfer coefficient = 15 W/m² K Thermal conductivity of steel = 50 W/m K Thermal conductivity of felt = 0.07 W/m K Moulded insulation Felt Moulded insulation K₂=0.09 W/mK Thermal conductivity of moulded insulation = 0.09 W/m 40 10. A 60 15°C Felt K₁=0.07 W/mK zzzzzzzz
Problem-1: Superheated steam at an average temperature 200°C is transported through a steel pipe (k = 50 W/m-K, D₁ = 8.0 cm, D₁ = 6.0 cm, and L=20.0 m). The pipe is insulated with a 4-cm thick layer of gypsum plaster (k = 0.5 W/m K). The insulated pipe is placed horizontally inside a warehouse where the average air temperature is 10°C. The steam and the air heat transfer coefficients are estimated to be 800 and 200 W/m2.K, respectively. Calculate (a) the daily rate of heat transfer from the superheated steam and (b) the temperature on the outside surface of the gypsum plaster insulation.
Q3:A- a cylindrical fuel rod consist of a fuel region of diameter (10mm). If the temperature at the center line of the fuel is (1800°C) and the heat generation rate is (q//=4x10 W/m'). 1- Find the temperature distribution along the radial direction of the fuel meat. Assume steady state one dimensional heat flow d?Tr 1 d + = 0 dr? r dr 2- Calculate the temperature at the surface of the fuel. Take the average thermal conductivity of the oxide fuel to be (1.9 W/m °C). 3- Calculate the temperature distribution along the radius of the fuel meat 4- Draw the temperature distribution along the radius of the fuel meat
Task 3 Superheated steam at 575°C is routed from a boiler to the turbine of an electric power plant through steel tubes (k = 35 W/m K) of 300 mm inner diameter and 30 mm wall thickness. To reduce heat loss to the surroundings and to maintain a safe-to-touch outer surface temperature, a layer of calcium silicate insulation (k = 0.10 W/m K) is applied to the tubes, while degradation of the insulation is reduced by degradation of the insulation is reduced by wrapping it in a thin sheet of aluminium having an emissivity of = 0.20. The air and wall temperatures of the power plant are 27°C. Assume that the inner surface temperature of a steel tube corresponds to that of the steam and the convection coefficient outside the aluminium sheet is 6 W/m²K, (a) What is the minimum insulation thickness needed to ensure that the temperature of the aluminium does not exceed 50°C? (b) What is the corresponding heat loss per unit meter? (c) What is the difference between lagged and unlagged pipes in…
Please solve the overall heat loss and the temperature profile at each interface.*Disregard the similar question asked before this, the given in that question is incomplete.
The rate at which energy must be dissipated away from single integrated circuits (computer chips) continues to increase as transitors continue to shrink in size and more and more computations are being completed in smaller and smaller volumes. The maximum chip temperature, however, has not changed much over time and remains around Tc = 75 °C. To increase the rate of dissipation of thermal energy away from a new chip, it is proposed to add a 5 x 5 array of copper pin fins to the chip. Each fin will be individually joined to the chip surface such that there is a minimal contact resistance between the fin and the chip. The diameter of the fins is df = 1 mm and the length is Lf = 15 mm. The chip is square, with a side length of W= 15 mm. It is so thin that it can be treated as having a single temperature. A dielectric liquid flows over the outer surface of the chip and around the fins, with a temperature of T»,f= 20 °C and a convection coefficient of hf = 1150 W/m²-K. The chip is joined to…
spherical shaped vessel of 14 m outer diameter is 90 mm thick Find the rate of heat leakage, if the temperature difference between the inner and outer surfaces is 220°C Thermal conductivity of the material of the sphere is 0.083 W/mK
You are designing a 3m x 3m floor with radiant heating. The floor has 12 parallel pex pipes (k = 40 W/mK) of L = 3m, OD = 25mm and ID = 20mm. Hot water (TInfintiy 1 = 90oC, h = 200 W/m2K) runs through the pipes continuously. The surface below the pipes is perfectly insulated. Above the pipes, there is a 3mm layer of bonding material (? = 12 W/mK) and a 9mm layer of tile (k = 2 W/mK). Above the tile, there is air (TInfinity 2 = 25oC, h = 20 W/m2K). Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas), Hint: Assume that the “layer” of pipe starts at the center point (e.g. for conduction purposes, the pipe is OD divided by 2 thick). For convection, consider the entire pipe surface. a) What is the total heat rate entering the room above the floor? b) What is the temperature of the top of the tile?