Consider a long solid bar (K=45 W/m*k and ∝=12x10-6 m2/s) of square cross section that is infinity at uniform temperature of 450°C. The cross section of the bar is 20cmx20cm in size. All four sides of the bar are subjected to convection of ambient air at T=20°C with a heat transfer coefficient of (h=40 W/m2*K) Using the explicit finite difference method with a mesh (Δx=Δy = 10 cm), determine the centerline temperature “C” of the bar after 5 minutes.
Consider a long solid bar (K=45 W/m*k and ∝=12x10-6 m2/s) of square cross section that is infinity at uniform temperatu...
Consider a long solid bar (k=30W/m K and α 12X10-6 m /s) ofAare cro s section that is initially at uniform room temperature of 150° C. The cross seftion of the bar is 20 cm X 20 cm in size. All four side of the bar are subjected to donJeation td the ambient air at T-25oC with a heat transfer coefficient of h t45 W/m2K. Using the explicit finite difference method with a mesh Δ x = Δ y-10cm</determine the...
A long, hot AISI 304 stainless steel bar of rectangular cross section has dimensions w = 3 mm, W = 5 mm, and L = 100 mm. The bar is exposed to air that provides a heat transfer coefficient of h = 15 W/m2 · K at all exposed surfaces and air temperature is 300K. Determine an appropriate characteristic length Lc and the corresponding Biot number Bi that is associated with the transient thermal response of the solid object. State...
A long rectangular copper bar of a cross section of 2cm by 3cm and a long cylindrical copper rod of 2.2 cm in diameter are initially at a uniform temperature of 120 °C. They are then exposed to a cooling air stream at 22 °C with a heat transfer coefficient of 180 W/m-K. Taking the properties of the copper to be k = 400 W/m-K and p-8930 kg/m', and C -0.385 kJ/kg-K, determine: a How long would it take for...
Consider a rectangular bar of thermal conductivity k W/m-K and total length 2L, as shown in the figure, is connected to a hot surface that is at a temperature T1. The connection between the bar and the surface is imperfect and results in a thermal contact resistance of R’’ m2-K/W. The width of the rod into the depth of the paper is W meters and the thickness of the rod is t meters. The first section of the rod of...
Part 2 - Problems (75 marks) I. Copper fins (k 401 W/mK) of uniform square cross-section (2mm x 2mm) and length L 30mm are used in a fin array to enhance heat transfer from a 40mm x 40mm surface that is maintained at Tb 170°C. There are a total of 100 fins, and the tip of the fins is maintained at 35°C. Air circulates over the fin array with a temperature of To = 15°C and a convection coefficient of...
SKMM 3433 A solid body which is initially at a uniform temperature Tİ is exposed to an ambient air at temperature Te. Explain how you would determine the maximum amount of heat that can be transferred to the body. What does this amount of heat represent? Q2. (a) (5 marks) A wall ofa room is made of lightweight concrete material (ρ= 1600 kg/m.に0.79 W/m K and cp 0.84 kJ/kg K) with a thickness of 150 mm. Initially the wall is...
heat transfer Consider a long solid rod of constant thermal conductivity k whose cross section is a sector of a circle of radius ro and the angle a as shown in the figure. A peripheral heat flux 9":falls onto the peripheral surface. The plane surface at - O is kept isothermal at the ambient temperature T.. The other plane surface at = a loses heat by convection to the ambient. The steady temperature distribution is a function of r and...
A very long rod of 5-mm diameter and uniform thermal conductivity k = 25 W/m-K is subjected to a heat treatment process. The center, 30-mm-long portion of the rod within the induction heating coil experiences uniform volumetric heat generation of 7.5 x 106 W/m3. The unheated portions of the rod, which protrude from the heating coil on either side, experience convection with the ambient air at T∞ = 20 °C and h = 10 W/m2K. Assume that there is no convection...
4-79 White potatoes (k0.50 W/m-K and 0.13 X 10-6 m/s) that are initially at a uniform temperature of 25°C and have an average diameter of 6 cm are to be cooled by refrigerated air at 2°C flowing at a velocity of 4 m/s. The average heat transfer coefficient between the potatoes and the air is experimentally determined to be 19 W/m2.K Determine how long t wl take for the center temperature of the potatoes to drop to 6°C. Also, determine...
QUESTION 4 The temperature distribution for a long fin with uniform cross section is cosh[m(L - x)] cosh(ml) where b means base, O = T - To, m= rand A and P are the area and perimeter of the cross- section. K is in air at A long copper rod of diameter D = 1.5 cm, L = 20 cm, and thermal conductivity 380 W/ m 20°C. The temperature at the base is 150°C. If m = 6 m-7, the...