fundamentals of heat and mass transfer solutions manual phần 9 ppt

... history of the workpiece from the start of heating to the end of cooling; identify key features of the process; determine the total time requirement; and justify the lumped-capacitance method of analysis. SCHEMATIC: ASSUMPTIONS: ... M is the mass of PCM, and h fg is the heat of fusion of PCM. Irradiation: G = σT w = 5.67 × 10 -8 W/m 2 ⋅K 4 (1200 K) 4 = 117,573 W/m...

Ngày tải lên: 08/08/2014, 17:20

... value of the heat rate. PROBLEM 1. 39 KNOWN: Power consumption, diameter, and inlet and discharge temperatures of a hair dryer. FIND: (a) Volumetric flow rate and discharge velocity of heated ... Electrical heater is perfectly insulated from dryer wall, (3) Heater and switch are isothermal at T set , (4) Negligible heat transfer from sides of heater or switch...

Ngày tải lên: 08/08/2014, 17:20

... Temperature and volume of hot water heater. Nature of heater insulating material. Ambient air temperature and convection coefficient. Unit cost of electric power. FIND: Heater dimensions and insulation ... through a pipe of prescribed inner and outer radii. Emissivity of outer surface magnesia insulation, and convection coefficient. Temperature of ambient air and surr...

Ngày tải lên: 08/08/2014, 17:20

... T o and T ∞ , the relative amounts of heat transfer to the air and heat sink are determined by the values of h and t,c R. ′′ PROBLEM 4.54 (Cont.) The heat rate by convection between the bar and ... 243.1 235.0 223 .9 2 09. 8 194 .1 177.8 100 282.4 281.8 280.1 276 .9 271.6 263.3 250.5 232.8 213.5 125 310 .9 310.5 3 09. 3 307.1 303.2 296 .0 282.2 257.5 150 340.0 340.0 3...

Ngày tải lên: 08/08/2014, 17:20

... (L,45s) (mm) ( ° C) kW/m 2 kW/m 2 10 1 49. 8 -2 49. 8 +1 49. 8 5 1 49. 3 -2 49. 0 +1 49. 0 2 1 49. 4 -2 49. 1 +1 49. 0 COMMENTS: (1) The center temperature and boundary heat fluxes are quite insensitive to mesh ... 322.7 324.0 324.5 325 7 126 281.8 299 .5 310.5 317 .9 321.4 323.3 324.2 8 144 2 79. 8 296 .2 308.6 315.8 320.4 322.5 9 162 276.7 294 .1 306.0 314.3 3 19. 0 10 180 274.8...

Ngày tải lên: 08/08/2014, 17:20

... emissivity of Nichrome wire. Electrical current. Temperature of air flow and surroundings. Velocity of air flow. (a) Surface and centerline temperatures of the wire, (b) Effect of flow velocity and ... thickness and thermal conductivity of steel pipe. Temperature of water flow in pipe. Temperature and velocity of air in cross flow over pipe. Cost of producing hot...

Ngày tải lên: 08/08/2014, 17:20

... 1000 3.025 × 10 -2 348.6 91 5.0 2 95 0 4.321 × 10 -2 463.7 898 . 3 90 0 5.041 × 10 -2 524.6 891 .0 4 890 5.215 × 10 -2 5 39. 0 8 89. 5 Hence, we find 2 am,o m5.2210 kg/s T 890 K. − =×= & < COMMENTS: ... 8.34 KNOWN: Flow rate and inlet temperature of water passing through a tube of prescribed length, diameter and surface temperature. FIND: (a) Outlet water temperature a...

Ngày tải lên: 08/08/2014, 17:20

... ) D 1/4 5 1/4 D 4 /94 /9 9/1 69/ 16 0.5 892 .93 10 0.589Ra Nu2212.55 10.4 69/ Pr10.4 69/ 0.700 × =+=+=  ++   ( ) D 2 hNuk/D12.550.0 298 W/mK/0.040m9.36W/mK. ==⋅=⋅ Substituting numerical values, the heat loss ... on quality, x, at outlet of 30 m length of tube; (b) Effect of radiation on heat transfer and quality of outlet flow; (c) Effect of emissivity and ins...

Ngày tải lên: 08/08/2014, 17:20

... C r = 0.5 and NTU = 2 to obtain ε = 0. 693 . PROBLEM 11. 39 KNOWN: Pressure and initial flow rate of water vapor. Water inlet and outlet temperatures. Initial and final overall heat transfer coefficients. FIND: ... values of P and R as given by Fig. 11.11 with ( ) ( ) ( ) ( ) P9535/300350.23R300 196 /120351.22=−−==−−= giving F ≈ 1. Based upon CF arrangement, ( ) ( ) ( ) (...

Ngày tải lên: 08/08/2014, 17:20

... of ash deposit. Convection coefficient and temperature of gas flow over the tube. Temperature of surroundings. FIND: (a) Rate of heat transfer to tube without ash deposit, (b) Rate of heat transfer ... 13.1 09 KNOWN: Dimensions and emissivity of double pane window. Thickness of air gap. Temperatures of room and ambient air and the related surroundings. FIND:...

Ngày tải lên: 08/08/2014, 17:20