6 heat transfer enhancement

Ngày tải lên: 10/09/2015, 09:11

... (kg/m2s) Heat transfer coefficient, Uo (W/m2K) Results 0. 168 6 0.0133 16. 54 13.74 50 .60 0.07 0.81 0.74 401 265 9 0. 162 8 0.01 06 14 .68 12.38 30.40 0.01 0.75 0.74 318 25 06 0.1599 0.0 066 12. 06 10.51 ... (kg/m2s) Heat transfer coefficient, Uo (W/m2K) Results 0.2011 0.0179 25.31 28.28 46. 8 0.80 0.04 0. 76 538 3045 0.1799 0.0151 25 .66 28. 26 36. 9 0.82 0. 06 0. 76 4 56 2837 0.1282 0.0097 28 .60 31.00 16. 7 ... (kg/m2s) Heat transfer coefficient, Uo (W/m2 K) Results 0.1800 0.0171 25 .67 28 .64 44.5 0.83 0. 06 0.77 537 3 063 0.1725 0.0144 26. 78 29. 26 32.0 1.00 0.27 0.73 452 2920 0.1283 0.0093 28.71 30.91 16. 0...

Ngày tải lên: 05/09/2013, 16:10

... Convective Heat and Mass Transport edition Singapore: MacGraw Hill; 2005 doi:10.11 86/ 15 56- 276X -6- 3 76 Cite this article as: Sasmito et al.: Numerical evaluation of laminar heat transfer enhancement ... Conference, Rome, 6- 7 September 20 06 Sasmito et al Nanoscale Research Letters 2011, 6: 3 76 http://www.nanoscalereslett.com/content /6/ 1/3 76 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 ... et al Nanoscale Research Letters 2011, 6: 3 76 http://www.nanoscalereslett.com/content /6/ 1/3 76 diverse materials in heat transfer fluids, called nanofluids [ 16] Modern technology provides opportunities...

Ngày tải lên: 21/06/2014, 03:20

... critical heat flux of water in pool boiling heat transfer Appl Phys Lett 2003, 83:3374-33 76 Xuan Y, Li Q: Heat transfer enhancement of nanofluids Int J Heat Fluid Flow 2000, 21(1):58 -64 Wen D, ... Technol 2008, 1 86: 145-53 doi:10.11 86/ 15 56- 276X -6- 280 Cite this article as: Barber et al.: A review on boiling heat transfer enhancement with nanofluids Nanoscale Research Letters 2011 6: 280 Submit ... mechanisms of heat transport in nanofluids Heat Transfer Eng 2009, 30:11 36- 1150 Kakac S, Pramuanjaroenkij A: Review of convective heat transfer enhancement with nanofluids Int J Heat Mass Transf...

Ngày tải lên: 21/06/2014, 04:20

... recommendations 6. 1 217 Conclusions 217 6. 1.1 Corrugated surface 218 6. 1.2 Heat transfer over asymmetric dimples 218 vii 6. 1.3 6. 2 Heat transfer ... Chapter Heat transfer over protrusions 1 86 5.1 Configuration of protrusions 1 86 5.2 Results and Discussion 189 5.2.1 5.2.2 Distribution of local drag and heat transfer ... 265 D.4.3 Validation of results 266 D.5 Reτ → ∞ 267 D.5.1 S=0.5 267 D.5.2 S=1 268 Appendix...

Ngày tải lên: 10/09/2015, 09:10

... × 64 × 32 35.343 0.50 06 6433 86% 79% 64 × 64 × 64 17 .67 1 0.50 06 5928 91% 92% 32 × 128 × 32 35.343 0.2 368 64 40 89% 84% 64 × 128 × 64 17 .67 1 0.2 368 5932 94% 97% 96 × 128 × 96 11.781 0.2 368 5 861 ... Cf N u0 N u0 64 × 64 × 64 17 .67 1 0.50 06 0.004 5929 91% 92% 64 × 64 × 64 17 .67 1 0.50 06 0.002 5928 91% 94% 96 × 96 × 96 11.781 0.3572 0.002 5 861 95% 97% 128 × 128 × 128 8.8 36 0.2 368 0.003 5830 ... resolution 64 × 128 × 64 is a good compromise and yet accord reasonably accurate solution.) Mesh cells number (Nx × Ny × Nz ) Δx+ Δz + + Δymin Re 2H Cf 0 Cf N u0 N u0 16 × 64 × 16 70 .68 6 0.50 06 6857...

Ngày tải lên: 10/09/2015, 09:11

... 16 12 16 18 0.5 12 16 Y Y 12 16 -1.5 -2 24 23 -0.5 12 16 12 0 22 20 -1 12 16 18 16 16 18 18 20 22 22 -0.5 22 0.5 16 18 20 23 Y 0.5 18 20 16 12 20 18 12 16 Y 16 80 18 12 16 1.5 0.2 0.4 Z/λ 0 .6 ... 20 -1 0.5 16 12 -0.5 18 18 20 Y 18 0.5 12 16 Y 12 20 18 -1 Z/λ 0 .6 0.8 12 0.2 0.4 0 .6 Z/λ 0.8 Z/λ (c) (d) 2 1.5 1.5 12 19 8 16 16 12 12 16 -1 12 0.4 0 .6 0.8 -2 12 -1.5 0.2 -1.5 -0.5 16 -2 18 18 ... less than 1 06 1.5 12 20 0 12 -1.5 0.2 0.4 0 .6 0.8 -2 0.2 0.4 0 .6 0.8 Z/λ (a) (b) 2 1.5 1.5 12 16 12 16 -2 16 -1.5 0.4 12 -1 -2 0.2 18 18 0 18 -1.5 16 -0.5 18 21 22 20 18 18 18 16 12 16 12 20 20...

Ngày tải lên: 10/09/2015, 09:11

... symmetric dimple, which may be the cause of the enhancement of heat transfer 4.4.2 Mean characteristics of drag and heat transfer Since Case has higher heat transfer characteristics than Case 2, we ... reattachment point downstream restrains further enhancement of heat transfer; this implies that suppressing recirculation inside dimple enhances 164 heat transfer, which is consistent with our results ... -8 1 12 X -3 -6 -1 4 II III Z I Z Dx = 0% -8 -3 6 2 -2 6 -8 2 10 12 X (b) Case 3C.2* 12 (e) Case 3S.2 12 -12 - 16 12 10 X 0 -2 -4 -8 0 Z 8 Z -8 12 -12 12 4 -1 12 - 16 12 2 Dx = 15% 6 10 12 X 10...

Ngày tải lên: 10/09/2015, 09:11

... drag Nu/Nu0 4 .6 4.2 3.8 3.4 2 .6 2.2 1.8 1.4 Z Z Nu/Nu0 2.2 1.8 1 .6 1.4 1.2 0.8 8 10 10 10 15 10 X (a) 5% (b) 10% 10 10 Nu/Nu0 10 9.2 8.4 7 .6 6.8 5.2 4.4 3 .6 2.8 1.2 Z Z Nu/Nu0 7.5 6. 5 5.5 4.5 3.5 ... original run (d) F m/F m0 for additional run Nu/Nu0 10 9.2 8.4 7 .6 6.8 5.2 4.4 3 .6 2.8 1.2 Z Nu/Nu0 10 9.2 8.4 7 .6 6.8 5.2 4.4 3 .6 2.8 1.2 Z 10 10 10 15 10 15 X X (e) N u/N u0 for original run ... with larger 192 0.8 0 .6 0.4 0.2 Sm/Sm0 1 .6 1.2 0.8 0.4 -0.4 Z Z Sm/Sm0 6 8 10 10 10 15 10 X (a) 5% (b) 10% 0 Sm/Sm0 2.8 1.2 0.4 -0.4 Sm/Sm0 2.2 1.4 0 .6 -0.2 -1 Z Z 15 X 6 8 10 10 10 15 10 X (c)...

Ngày tải lên: 10/09/2015, 09:11

... Coordinates……………………………………………… 158 6. 1 Discretization of governing equations………………………………………158 6. 2 Implementation of CLEARER algorithm………………………………… 162 6. 2.1 The predictor step of CLEARER algorithm………………………… 162 6. 2.2 The ... measure the heat transfer coefficient of a fin and tube heat exchanger Ay et al.(2002) and Bougeard(2007) used infrared thermography technique to measure local heat transfer coefficient on heat exchanger ... alignment on heat transfer characteristics of fin-and-tube heat exchanger with large fin pitch Wang et al.(1997a) studied the heat transfer and pressure drop performance of plate finned tube heat exchangers...

Ngày tải lên: 11/09/2015, 16:02

... conducted 154 Heat Transfer – Engineering Applications Counter heater Thermocouple Steel plate Φ74 .6 Rubber thermocouples Wood Plate a Rubber Thermocouple 120 Sheathed heater A B c d Mold 74 .6 60 Thermal ... (1/s) Ei/R (K) k1 1.034×107 1. 166 ×104 1.387×10-1 3.827 k2 3.159×1013 1. 466 ×104 5.492×108 9.973 k3 2.182×107 8.401×103 1.880×109 9. 965 k4 1.089×107 8.438×103 1. 160 ×109 9. 863 k5 1.523×109 1.119×104 ... analysis  166 Heat Transfer – Engineering Applications Heating wall Temperature T (℃) 150 r mm 10 20 30 35 100 50 Measured Tw Predicted TR 0 60 120 180 Elapsed time (min) Degree of cure  Heat...

Ngày tải lên: 18/06/2014, 22:20

... 9. 863 8.891 6. 640 10.413 10.339 9.025 6. 699 Nu R 0.000 0.000 0.000 0.000 36. 733 36. 759 36. 841 36. 8 46 0.000 0.000 0.000 0.000 36. 4 86 36. 513 36. 704 36. 808 0.000 0.000 0.000 0.000 36. 047 36. 073 36. 313 ... 36. 047 36. 073 36. 313 36. 531 Right hot wall Nu C 2.523 2.220 1.118 1.1 16 2.105 1.874 1. 368 1.357 5.090 4.983 2.997 1.454 3 .63 9 3.530 2. 068 1.4 46 9.904 9. 863 8.891 6. 640 6. 9 46 6.914 6. 050 4.178 Nu R ... 39.843 5.090 4.983 2.997 1.454 42 .62 4 42.499 40.787 39.982 9.904 9. 863 8.891 6. 640 46. 460 46. 412 45.338 43.230 Table Nusselt numbers estimated The rate of heat transfer across the enclosure is...

Ngày tải lên: 19/06/2014, 10:20

... (1995) Single phase liquid jet impingement heat transfer, Advances in Heat Transfer, vol 26, (March 1995), pp 105-217, ISSN 0 065 -2717 2 16 Developments in Heat Transfer Wolf, D;, Incropera, F.P & Viskanta, ... (1994) Air impingement heat transfer at low nozzle spacings, Int J Heat Mass Transfer, vol 37, no 12, (August 1994), pp 168 7- 169 7, ISSN 0017-9310 Martin, H (1977) Heat and mass transfer between impinging ... Advances in Heat and Mass Transfer, HTD-vol 362 /BEDvol 40, pp 123-32, ISSN 0272- 567 3 Colvin, D.P & Mulligan, J.C (19 86) Spacecraft Heat Rejection Methods : Active and Passive Heat Transfer for...

Ngày tải lên: 19/06/2014, 10:20

... the cooler (cm) 26. 0 13.0 2 .6 0.0 26. 0 13.0 2 .6 0.0 Thot Calc (ºC) 261 3 56 613 1018 491 794 1098 1070 Thot Exp (ºC) 1102 1092 Heat flux Calc (kW/m2) 135 187 310 4 76 94 144 382 733 Heat flux Exp ... water temperature change (ºC) 16 13 15 26 25 24 28 27 28 Mass change (g) Heat flux (kW/m2) Remarks - 80 - 63 - 128 198 150 165 98 158 59 350 427 492 569 820 788 61 3 8 86 919 Not treated Not treated ... interfacial heat transfer, Metallurgical Transactions B, 16B, 3, pp 585 - 594 Incropera F P and DeWitt D P, Fundamentals of Heat and Mass Transfer 4th Edition, John Wiley & sons., New York, U.S.A., 1996...

Ngày tải lên: 19/06/2014, 12:20

... 8.3 36 Water+Cu Water+ Al2 O3 ϕ = 0.1 ϕ = 0.2 ϕ = 0.1 ϕ = 0.2 d = 0.4L 5.030 6. 591 4.974 6. 451 5.232 6. 667 5.153 6. 511 9.434 10.05 9.157 9.435 d = 0.5L 5.2 96 6.941 5.237 6. 793 5.571 7.051 5.481 6. 877 ... smaller heat transfer c p [ J/kgK ] ρ[kg/m3 ] k[W/mK ] β[·10−5 K −1 ] α[·10−7 m2 /s] pure water 4179 997.1 0 .61 3 21 1.47 Cu 385 8933 400 1 .67 1 163 Al2 O3 765 3970 40 0.85 131.7 TiO2 68 6.2 4250 ... Methods for Heat Transfer Simulation Fast BEM Based Methods for Heat Transfer Simulation 211 studied turbulent heat transfer behaviour of nanofluid in a circular tube, heated under constant heat flux...

Ngày tải lên: 20/06/2014, 01:20

... 27.5 8.3 ~ 10.0 6. 6 ~ 9.1 7.0 ~ 7 .6 7.7 ~ 8.2 8 .6 ~ 8.9 5.7 ~ 6. 9 7.4 ~ 9.5 6. 3 ~ 6. 6 28 ~ 66 34 ~ 76 40 ~ 56 20 ~ 29 11 ~ 17 24 ~ 42 26 ~ 55 30 ~ 35 Table Space experimental conditions and the ... (W/cm2) superheat ΔTsat (K) I-1 I-2 I-3 I-4 I-5 II-1 II-2 III-1 90.8 97.3 102.3 105.7 111.7 57.2 91.1 65 .5 36. 9 25.8 21.8 19.5 18.4 24.5 18.8 27.5 8.3 ~ 10.0 6. 6 ~ 9.1 7.0 ~ 7 .6 7.7 ~ 8.2 8 .6 ~ 8.9 ... Calculated value 19.9 20.0 15 .6 16. 2 13.0 13 .6 11.1 12.1 10.4 10.5 9.7 9.5 Corresponding period (μs) Measured value Calculated value 3. 56 3 .62 2.43 2. 76 2.24 2.24 2. 06 2.07 1.87 1.90 1.87 1.82 Table...

Ngày tải lên: 20/06/2014, 06:20

... 27.5 8.3 ~ 10.0 6. 6 ~ 9.1 7.0 ~ 7 .6 7.7 ~ 8.2 8 .6 ~ 8.9 5.7 ~ 6. 9 7.4 ~ 9.5 6. 3 ~ 6. 6 28 ~ 66 34 ~ 76 40 ~ 56 20 ~ 29 11 ~ 17 24 ~ 42 26 ~ 55 30 ~ 35 Table Space experimental conditions and the ... (W/cm2) superheat ΔTsat (K) I-1 I-2 I-3 I-4 I-5 II-1 II-2 III-1 90.8 97.3 102.3 105.7 111.7 57.2 91.1 65 .5 36. 9 25.8 21.8 19.5 18.4 24.5 18.8 27.5 8.3 ~ 10.0 6. 6 ~ 9.1 7.0 ~ 7 .6 7.7 ~ 8.2 8 .6 ~ 8.9 ... Calculated value 19.9 20.0 15 .6 16. 2 13.0 13 .6 11.1 12.1 10.4 10.5 9.7 9.5 Corresponding period (μs) Measured value Calculated value 3. 56 3 .62 2.43 2. 76 2.24 2.24 2. 06 2.07 1.87 1.90 1.87 1.82 Table...

Ngày tải lên: 21/06/2014, 02:20

... Pressure (MPa) 90 .69 41 62 5 90.352 62 5 85.48 62 3 134.87–589 113. 56 573 143.47 60 0 200–553 273–498 177.83 60 0 182.55 60 0 2 16. 37 60 0 195.495–700 83.8 06 700 283 63 5 2 16. 592–1100 68 .127–1000 279.47–700 ... Trans ASME, 66 , 67 1 68 4 Rohsenow, W M (1952) A Method for Correlation Heat Transfer Data for Surface Boiling in Liquids, Trans ASME, 74, 969 –975 Rohsenow, W M., and Choi, H Y (1 961 ) Heat Mass and ... Sons / Page 46 / 2nd Proofs / Heat Transfer Handbook / Bejan 47 THERMOPHYSICAL PROPERTIES OF FLUIDS 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40...

Ngày tải lên: 05/07/2014, 16:20

... 0.5 96 Now from eqn (3.17), we find that Q = ε Cmin (Thin − Tcin ) = 0.5 96( 10, 000)(110) = 65 5, 60 0 W = 65 5 .6 kW Finally, from energy balances such as are expressed in eqn (3.4), we get Q 65 5, 60 0 ... Cmin (Thin − Tcin ) (3. 16) where Cmin is the smaller of Cc and Ch The effectiveness can be interpreted as ε= actual heat transferred maximum heat that could possibly be transferred from one stream ... analyze heat convection in pipes and tubes Heat exchanger design 1 26 §3.4 Eqn (3.22) defines the curve for Cmin /Cmax = in all six of the effectiveness graphs in Fig 3. 16 and Fig 3.17 3.4 Heat exchanger...

Ngày tải lên: 07/08/2014, 10:20