The engine cylinder of a motorcycle is constructed of aluminum alloy ((T= 400 Kk 186 W/m. K) and is of height H 0.15 mand outside diameter D 50 mm. Under typical operating conditions the outer surface of the cylinder is at a temperature of 500 Kand is exposed to ambient air at300 K with afconvection coefficient of 50 W/m K Annular fins are integrally cast with the cylinder to increase heat transfer to the surroundings. Consider five such fins, which are of thicknesst =6 mm.length L = 20 mm, and equally spaced. What is the increase in heat transfer due to use of %3D %3! the fins?

The engine cylinder of a motorcycle is constructed of aluminum alloy ((T= 400 Kk 186 W/m. K) and is of height H 0.15 mand outside diameter D 50 mm. Under typical operating conditions the outer surface of the cylinder is at a temperature of 500 Kand is exposed to ambient air at300 K with afconvection coefficient of 50 W/m K Annular fins are integrally cast with the cylinder to increase heat transfer to the surroundings. Consider five such fins, which are of thicknesst =6 mm.length L = 20 mm, and equally spaced. What is the increase in heat transfer due to use of %3D %3! the fins?

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

The wall of a furnace consists of a 0.85 cm-thick layer of steel (ks = 15.1 W/m/K) and an outer layer of brick (kb = .72 W/m/K). The outer surface temperature of the brick, To = 50oC, and is exposed to convection with air at 20oC providing a heat transfer coefficient of 150 W/m^2/K. Determine the steady temperature at the steel brick interface, Tmid, and on the exposed steel surface, Ti, if the brick layer has thickness Lb = 5 cm.
Q3/ A 6(m) long 2(kW) electrical resistance wire is made of 0.2(cm) diameter stainless steel (k = 15.1 W/m °C). The resistance wire operates in an environment at 30°C with a heat transfer coefficient of 140 (W/m?. °C) at the outer surface. Find the temperature distribution equation and determine the surface temperature of the wire.
The length of one side of a cube-shaped freezer cabinet is 11.8 m. your closetits base is perfectly insulated against heat transfer and the inner surface temperature is –5 °C, the outer surface temperatureand it is 59°C. To ensure that the thermal load of the cabinet is not less than 0.59 kWThe thickness of the styrofoam foam insulation (k=0.03 W/mK) to be applied to the upper and side surfacesWhat should be less?
Example: Steam in a heating system flows through tubes whose outer diameter isD1=3 cm and whose walls are maintained at: = 1.5 cm 2= 3 cm temperature of 120°C. Circular aluminun fins ( k=180 W/m °C) of outer diamete D2 6 cm and constant thickness t =2 mn T r32 mm are attached to the tube, as shown in Fig The space between the fins is 3 mm, an thus there are 200 fins per meter lengtl of the tube. Heat is transferred to th surrounding air at T= 25°C, with a combined heat transfer coefficient of h= 60 W/m2 °C. Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins. S 3 mm
A furnace wall is made up of three layer of thickness 150 mm, 110 mm, and 125mm with thermal conductivity of 1.65 W/m-K, k2, and 9.2 W/m-K respectively. Theinside is exposed to gases at 1050°C with a convection coefficient of 25 W/m2-Kand the inside surface temperature is at 900°C, the outside air temperature is at30°C with convection coefficient of 12 W/m2 -K. Calculate:a. the unknown thermal conductivity;b. the outside surface temperature and mid-plane temperatures in °F.
A pipe carrying hot gasses is insulated with a material having a thermal conductivity of 0.15 W/mK. The average local heat transfer coefficient by convection to the ambient air is 3 W/m K. The critical diameter of the pipe under 35. these conditions is (a) 100 mm (c) 160 mm (b) 130 mm (d) 200 mm
Thermal jackets are typically put on cryogenicstorage tanks to minimize the heat transfer gainsfrom the surroundings. Consider a cylindercontainer that is 1.5 m long made from steel (k = 750W/m.K) with an inner diameter of 0.5 m and outerdiameter of 0.7 m. If the liquefied natural gas (LNG)inside the cylinder is maintained at 90 K, ambientconditions are Tamb = 20 °C, h = 7 W/m2.K. What isthe required thermal jacket thickness to maintainthe outer temperature of that jacket of 15 °C? (Takea thermal conductivity of the insulation to be kins =0.015 W/m.K). Image credit: Okorder. Image forillustrative purposes only.
The outer surface of an oil heater at a uniform temperature of 100°C is to be filled with straight rectangular fins having a uniform thermal conductivity of 180 W/m.K. The ambient air temperature is 25°C and the heat transfer coefficient is 100 W/m².K. The fin thickness t-1mm, width w= 1m and its length is L= 10mm. If the heat transfer from the tip of the fin by convection, calculate fin efficiency and effectiveness. Tь =100 с Too = 25°C h = 100 W/m2-K L = 10 mm Air k= 180 W/m-K t = 1 mm
Thermal jackets are typically put on cryogenicstorage tanks to minimize the heat transfer gainsfrom the surroundings. Consider a cylindercontainer that is 1.5 m long made from steel (k = 750W/m.K) with an inner diameter of 0.5 m and outerdiameter of 0.7 m. If the liquefied natural gas (LNG)inside the cylinder is maintained at 90 K, ambientconditions are Tamb = 20 °C, h = 7 W/m2.K. What is the required insulationmaterial to maintain the outer temperature of that jacket of 15 °C? Usethe end of the book and write your assumption with the right value.(Take a maximum allowed jacket thickness of Lins = 7 cm)
The 0.5 m x 1.2 m wall of an industrial furnace is constructed from L = 0.15-m-thick fireclay brick having a thermal conductivity of 1.7 W/m-K. The temperature distribution, at an instant in time, is T(x) = a + bxwhere a = 1400 K and b = -950 K/m. Determine the heat fluxes, q, and heat rates, q,, atx = 0 and.x = L, in W/m2 and W respectively. Do steady-state conditions exist? i W/m? i W/m? Ix=0 = i W i W Ix=L = Steady-state conditions exist. ||
Plate glass 5 mm thick at 200°C is to be cooled from both sides using air at 40°C. If surface cracks are to be avoided, determine the maximum value of convective heat transfer coefficient. Material properties are density = 2500 kg/m3, specific heat 670 J/kgK. Thermal conductivity 0.744 W/mk. Also determine the time required in this to cool the plate to 80°C.
A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated in the sketch. On a cold day, the temperature and the convection heat trans- fer coefficients are Tei=20°C, h;=30 W/m²K and Teo=-15°C, h, =60 W/m²K. The wall surface area is 350 m?. Determine the total heat loss through the wall. Conductivities are given as k,=0.038 W/m.K, k,=0.012 W/m.K, k,=0.17 W/m.K. Glass fiber blanket (28kg/m³), k, Plaster board, k, Plywood siding, k, 11 11 10mm 100mmH E20mm