1. HW # 5 /Tutorial # 5 WRF Chapter 19; WWWR Chapter 20 ID Chapters 7-9 Tutorial # 5 WRF#19.3; WRF#19.8; WWWR #20.13,; WRF#19.23, WWWR#20.42. To be discussed on Feb. 16, 2016. By either volunteer or class list. Correction: #20.42: Table: Unit for C p should be corrected from J/kg-K to kJ/kg-K.

2. Convective Heat Transfer Correlations

3. Natural Convection

9. Horizontal Plates McAdam’s Correlations: Hot surface facing up or cold surface surfacing down H C H C

10. Horizontal Cylinders g

13. In each of the correlations to follow the temperature of the hotter of the two large surfaces is designed in T 1, and the cooler surface is at temperature T 2. Fluid properties are evaluated at the film temperature, T f = (T 1 + T 2 ) / 2. Convective heat flux is expressed as qAqA = h(T 1 - T 2 )

17. Example 1

19. H H

20. Initial Guess T = 385K, Resulting T=381.1K  Second Iteration

23. Forced Convection For Internal Flow

28. Turbulent Flow

30. Example 2 Hydraulic fluid (MIL-M-5606), in fully developed flow, flows through a 2.5 cm diameter copper tube, with a mean velocity of 0.05 m/s. The oil enters at 295K. Steam condenses on the outside tube surface with an effective heat transfer coefficient of 11400 W/m 2 -K. Find the rate of heat transfer to the oil. Ro Ri Rc Rc << Ro, Ri 295K

31. Example 2 Ro Ri =(295+305)/2 Rc Rc << Ro, Ri 295K 305K?

32. =373-(373-300)*[98.1/(98.1+11400)] =372.3K

34. Example 3

37. Forced Convection For External Flow Flow Parallel To Plane Surface

38. Cylinders In Crossflow

43. Tube Banks In Crossflow S L : Center-to-center distance between tubes along the direction of flow S T : Center-to-center distance between tubes normal to the direction of flow

44. Adapted from ID Page 437