... − T∞ ) W q′=0 .8 ( 0.2m ) 5.67 × 10 8 486 4 − 2 984 K K4 m ⋅ W +20 (π × 0.2m ) ( 486 -2 98) K m2 ⋅ K ( ) q′= (1365+2362 ) W/m=3727 W/m < With the insulation, the thermal circuit is of the form Continued ... 10−3 kW W = 625 kWh With a unit electric power cost of $0. 08/ kWh, the annual cost of the heat loss is C = ($0. 08/ kWh)625 kWh = $50.00 Hence, an insulation thickness of δ = 25 mm < will satisfy the ... 298K = 20 ⋅K ln ( 0.3m/0.2m ) m 2π ( 0.0 58 W/m ⋅ K ) W π (0.3m ) Ts,o − 2 984 K +0 .8 × 5.67 ×10 -8 ⋅ K4 m ( ( ) ) ( ) ( ) ( ) By trial and error, we obtain Ts,o ≈ 305K in which case q′= ( 486 -305)...
... K , ν = 15 .89 × 10 −6 m / s, Pr = 0.707 (a) With Re D = VD o / ν = m / s × 0.1m / 15 .89 × 10 −6 m / s = 18, 88 0, application of the Churchill-Bernstein correlation yields 0.62 ( 18, 800 ) 1/ Nu ... 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 electric ... 1.648E4 */ Aw 6.24 etaf 1.44 etaoc 0.9 78 /* Correlation results and air thermophysical properties at Tf NuLbarPr ReL Tf hLbar k nu uinf 2294 0.7035 1.63E6 325 53 .82 0.0 281 5 1 .84 1E-5 25 m 0. 981 4...
... Cmin/Cmax = (5,000 × 41 78) /(10,000 × 4 188 ) = 0.499 Combining Eqs (1) and (2), find Th,o = 80 °C − 0.7 × 3 48. 2 × 103 W / (10,000/3600 ) k g / s × 4 188 J / k g ⋅ K ( Th,o = ( 80 − 21.0 ) ° C = 59°C ... ⋅ K " 1 787 2250 2690 3112 ' h o W / m2 ⋅ K " 38. 4 38. 4 38. 4 38. 4 ' U W / m2 ⋅ K " ' 37.6 37 .8 37.9 37.9 Note that while hi varies nearly 50%, there is a negligible effect on the value of U COMMENTS: ... = 0. 088 = ηo,h mLf 11.33 Substituting into Eq (2), 0.01 UA = + + 0. 088 × 5000 × 0. 785 0.706 × 52.7 × 0. 785 ( −1 W W = 25.6 K K ) Hence, with Cmin = m cp = 0.03 kg / s × 10 08 J /...
... Composition 683 746 12 .8. 4 Humidification 750 12 .8. 5 Evaporative Cooling 752 688 11.9.6 Chemical Potential for Ideal 689 Chapter Summary and Study Guide 690 12 .8. 6 Adiabatic Mixing of Two Moist Air Solutions ... Mixtures 82 2 13.7.2 Standard Chemical Exergy of Other 82 5 13 .8 Applying Total Exergy 82 6 13 .8. 1 Calculating Total Exergy 82 6 Substances 13 .8. 2 Calculating Exergetic Efficiencies 82 9 Chapter Summary ... Inequality 264 Chapter Summary and Study Guide 266 Using Entropy 284 6.6 285 Introducing the T dS Equations 286 Entropy Change of an Incompressible Substance 288 Entropy Change of an Ideal Gas 289 6.5.1...
... for ISBN: 0- 080 -44015-0 (Hardbound edition) ISBN: 0- 080 -440 28- 2 (Paperback edition) ~The paper used in this publication meets the requirements of ANSI NISO Z39. 48- 1992 (Permanence of Paper) Printed ... lay-out of the cabins, etc These details are, of course, irrelevant to the objectives of that model Other models of the ship will serve other aims: blue prints of the electrical wiring, lay-out of ... 8. 3 Characteristics and Structure of Ecotoxicological Models 8. 4 An Overview: The Application of Models in Ecotoxicology 8. 5 Estimation of Ecotoxicological...