Chapter 4, Problem 45P

Water at 20 o C enters the 4 cm-diameter, 14 m-long tube at a rate of 0.8 kg/s. The surfacetemperature of the pipe is maintained at 165 o Cby condensing geothermal stream at the shellside of the heat exchanger. Use water properCesat 85 o C for all calculaCons.(a) Show that the water flow is turbulent and thermally fully developed. (b) EsCmate the heat transfer coefficient for convecCve heat transfer from the pipe to the water. For a fully developed turbulent flow within the smooth pipe, the Nu number can becalculated from the following equaCon:(c) Calculate the exit temperature of the water. (d) Share your opinion on whether the use of water properties at 85°C is appropriate. Yes or No because:

Consider a hot automotive engine, which can beapproximated as a 0.5-m-high, 0.40-m-wide, and 0.8-m-long rectangular block. The bottom surface of the block isat a temperature of 100°C and has an emissivity of 0.95.The ambient air is at 20°C, and the road surface is at25°C. Determine the rate of heat transfer from the bottomsurface of the engine block by convection and radiationas the car travels at a velocity of 80 km/h. Assume theflow to be turbulent over the entire surface because of theconstant agitation of the engine block. a) Calculate convective heat transfer coefficient (h). b) Calculate the total heat transfer rate

8 mm- Top view -200 mm-180 mm- D B B 12 mm Side view B -8 mm D PROBLEM 1.56 In an alternative design for the structure of Prob. 1.55, a pin of 10-mm-diameter is to be used at A. Assuming that all other specifications remain unchanged, determine the allowable load P if an overall factor of safety of 3.0 is desired. PROBLEM 1.55 In the structure shown, an 8- mm-diameter pin is used at A, and 12-mm- diameter pins are used at B and D. Knowing that the ultimate shearing stress is 100 MPa at all connections and that the ultimate normal stress is 250 MPa in each of the two links joining B and D, determine the allowable load P if an overall factor of safety of 3.0 is desired. 20 mm P 8 mm- 12 mm- Front view

Where on the beam below is the Maximum Deflection likely to occur? 2P A "ती Point A Point B Point C Point D Point B or Point D ८ B प

Sign in ||! PDE 321 proje X IMB321 PDF Lecture 5 X PDF Planet Ec X PDF Planet Ec X PDF PEABWX PDF meeting x PDF GSS Quo X PDF File C:/Users/KHULEKANI/Downloads/CIVE%20281%20Ass-2.pdf Draw | | All | a | Ask Copilot + 1 of 7 | D SOLUTION B PROBLEM 12.16 Block 4 has a mass of 40 kg, and block B has a mass of 8 kg. The coefficients of friction between all surfaces of contact are μ, = 0.20 H = 0.15. Knowing that P = 50 N→, determine (a) the acceleration of block B, (b) the tension in the cord. Constraint of cable: 2x + (x-x1) = x + x = constant. a+ag = 0, or aB = -a Assume that block A moves down and block B moves up. Block B: +/ΣF, = 0: NAB - WB cos 0 = 0 =ma: -T+μN + Wsin = We as g + ΣΕ We Eliminate NAB and aB- NAB B Nas HN UNA A NA -T+W(sin+μcоsе) = WB- g VD"M- g Block A: +/ΣF, = 0: NA-NAB - W₁cos + Psinė = 0 N₁ = N AB+W cose - Psin = (WB+WA)cose - Psinė ΣF=ma -T+Wsino-FAB-F + Pcos = CIVE 281 X + Ждал g Q | го || حالم ☑

Where on the below beam is the Maxiumum Slope likely to occur? 120 Point A Point B Point C Point B or Point C B с

A very thin metallic sheet is placed between two wood plates of different thicknesses. Theplates are firmly pressed together and electricity is passed through the sheet. The exposed surfaces ofthe two plates lose heat to the ambient fluid by convection. Assume uniform heating at the interface.Neglect end effects and assume steady state.[a] Will the heat transfer through the two plates be the same? Explain.[b] Will the exposed surfaces be at the same temperature? Explain

Design consideration requires that the surface of a small electronic package be maintained at atemperature not to exceed 82 o C. Noise constraints rule out the use of fans. The power dissipated inthe package is 35 watts and the surface area is 520 cm2 . The ambient temperature and surroundingwalls are assumed to be at 24 o C. The heat transfer coefficient is estimated to be 9.2 W/m2- oC andsurface emissivity is 0.7. Will the package dissipate the required power without violating designconstraints?

Consider radiation from a small surface at 100 oC which is enclosed by a much larger surface at24 o C. Determine the percent increase in the radiation heat transfer if the temperature of the smallsurface is doubled.