Hint:p(uco)?2Table 7.7 (pages 484 and 485 7th ed.; page 354 and 355 8th ed.)TABLE 7.7 Summary of convection heat transfer correlations for external flow*CorrelationGeometryConditions8 - Sx Re,12(7.19)Flat plateLaminar, T,C,-0.664 Re, a(7.20)Flat plateLaminar, local, T,Nu, = 0.332 Re Pr(7.23)Flat plateLaminar, local, T,. Prz0.68, -8 Pr¯(7.24)Flat plateLaminar, T,C, = 1.328 Re,"-12(7.29)Flat plateLaminar, average, T,Nu, = 0.664 Reļª Pr(7.30)Flat plateLaminar, average, T,. Prz 0.6Nu, -0.564 Peļ?(7.32)Flat plateLaminar, local, T. Pr s0.05, Pe, z 100C-0.0592 Re,"(7.34)Flat plateTurbulent, local, T, Re, s 10*8 -0.37x Re,(7.35)Flat plateTurbulent, T, Re, < 1ơTABLE 7.7 (Continued)CorrelationGeometryConditionsNu, = 0.0296 Re" PraTurbulent, local, T. Re, 5 10°,0.6 s Prs 60(7.36)Flat plateC = 0.074 Rej15 – 1742 Rej'(7.40)Flat plateMixed, average, T,, Re,, = 5 × 10',Res 10Nu, = (0.037 Ref – 871)PrMixed, average, T,, Re,, = 5 × 10',Res 10', 0.6 s Prs 60(7.38)Flat plate Outside air ( v =15.89 x 10-6 m²/s, p= 1.16 kg/m³, Pr=0.707, k=0.0263 W/mK) withtemperature of T-12 °C flows over a flat glass window (kglass=1.05W/mK) with L=0.5m lengtlthe air velocity is measured as U=1.25 m/s and the glass thickness is t= 50 mm, calculate:1. Reynolds number at the glass edge (i.e. point A)-Is the flow laminar or turbulent?2. Average shear stress on outer surface of the glass3. Velocity boundary layer thickness at the glass edge (point A)4. Average convective heat transfer coefficient on outer surface of the glassA

In general, there are three modes by which heat gets transferred from one place to another. The…

Outside air ( v =15.89 x 106 m2/s, p= 1.16 kg/m3, Pr=D0.707, k=0.0263 W/mK) with temperature of T=-12 °C flows over a flat glass window (kglass=1.05W/mK) with L=0.5m lengt the air velocity is measured as U=1.25 m/s and the glass thickness is t= 50 mm, calculate: 1. Reynolds number at the glass edge (i.e. point A)-Is the flow laminar or turbulent? 2. Average shear stress on outer surface of the glass 3. Velocity boundary layer thickness at the glass edge (point A) 4. Average convective heat transfer coefficient on outer surface of the glass

Outside air ( v =15.89 x 106 m2/s, p= 1.16 kg/m3, Pr=D0.707, k=0.0263 W/mK) with temperature of T=-12 °C flows over a flat glass window (kglass=1.05W/mK) with L=0.5m lengt the air velocity is measured as U=1.25 m/s and the glass thickness is t= 50 mm, calculate: 1. Reynolds number at the glass edge (i.e. point A)-Is the flow laminar or turbulent? 2. Average shear stress on outer surface of the glass 3. Velocity boundary layer thickness at the glass edge (point A) 4. Average convective heat transfer coefficient on outer surface of the glass

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.54P

See similar textbooks

Similar questions

Air at atmospheric pressure enters a heating duct with dimensions of 3 x 6 in. The air enters the 16 ft long duct with a temperature of 32 fahrenheit, and the duct surface is maintained at 150 fahrenheit. If the air exit temperature is to be 68 fahrenheit, what is the air flow, in lb/hr? (answer in whole number) For air, R = 53.342 ft-lbf/lbm-R, k = 0.173 Btu-in/ft2-hr-F, and cp = 0.24 Btu/lbm-
Topic: Heat transfer Completely solve and box the final answer. 1. A 20degC water flows to 50cmx60cm flat plate with velocity of 5.2m/s . The flat plate surface temperature is maintained at 40deg C. The air flows parallel to the 50cm side of the plate. If the kinematic viscosity of water is 78x10-8 m2/s, at what length the flow become turbulent?
Q 3(c) Consider a cylindrical copper rod in which there is a unifom volumetric heating q = 12 kW/m³. The rod is in a cross flow of air at velocity and temperature which are v. = 10 m/s and T, = 350 K respectively. The rod surface temperature is Ts = 400K. The rod outer diameter and length are D = 5 cm and L = 50 cm respectively. Assume natural convection and radiation to be negligible and you can neglect heat transfer from the tips of the cylinder. I. Estimate the drag experienced by the rod. II. Find the average convection heat transfer coefficient which characterises convection from the outer surface using the appropriate correlation. III. Find the time rate of change of temperature of the full rod at the initial time when the rod is first placed in the air flow. Air Properties: At T. = 350 K: v = 20.92 x 10-6 m2/s, p = 1 kg/m3 k = 30 x 10-3W/m. K, Pr = 0.70 At T, = 400 K: p = 0.871 kg/m3 , u = 230 x 10-7 N.s/m?, Pr, = 0.69 Copper Properties: At T, = 400 K: p = 8900 kg/m , c = 385…
Atmospheric air at 5°C enters a thin walled 12cm diameter 20m long isothermal pipe (T=constant) at a velocity of 2.5m/s and leaves at 19°C. Estimate the surface temperature T3. Ts Air 5°C 12 cm 19°C 2.5 m/s 20 m
A thin metal sheet serving the purpose of an an anemometer has a length of 2.5 cm with a width of 8 mm. Wind with a temperature T, and velocity Uz blows parallel to the longest side of the sheet. The metal sheet is heated through a solar powered system giving our heat both sides at Q Watts. The anemometer is used in air with T,= 20C, C, = 1.005KJ/Kg K, v = 1.522 X 105 m2/s, p = 1.19 Kg/m³ and Pr = 0.72. The surface temperature, T, of the metal sheet was measured at the rear end however, it can be assumed to be constant. You are required to calculate an estimate of the wind speed when T = 32 °C and Q = 0.5 W.
Topic: Heat transfer Completely solve and box the final answer. A 20degC water flows to 50cmx60cm flat plate with velocity of 6m/s . The flat plate surface temperature is maintained at 40deg C. The water flows parallel to the 50cm side of the plate. If the kinematic viscosity of water is 78x10-8 m2/s, What is the local heat flux (Q/A) at the end of the plate (k=0.72 W/m deg C, Re=3840000, and Pr=0.7)?
Water is entering a heated tube at mass ow rate of 1.2 kg/s. The temperature at the inlet is 20 C and at the outlet is 80 C. Assume the surface temperature of the tube is 100 C. The convection coe cient of the water ow is 28 W=m2 C. The speci c heat and density of water can be assumed to be 4180 J=kg C and 990 kg=m3. What is the rate of heat transfer to water during this proces
A lead pipe has 2 cm inside diameter, 3 cm outer diameter, length of 130 cm. Liquid water at 4°C flows through the pipe with a bulk velocity of 2.50 km/hr. Air is blown around the outside of the pipe at 20 deg C. The inside wvall of the said pipe has a temperature of 8 deg Celsius. Density of liquid water= 1000 kg/m' Cp water=4.210 J/kgK Viscosity of liquid water= 1.5674 x10° Pa.s thermal conductivity of lead = 35 W/mK Find: Overall heat coefficient (U) based on outside surface area b. System's heat transfer rate Prandtl (Pr), Reynolds (Re) numbers and type of flow а. с.
Required information Water at 20°C is flowing with velocity of 0.89 m/s between two parallel flat plates placed 1 cm apart. Given: The properties of water at 20°C are p= 998.0 kg/m3, µ = 1.002 x 103 kg/m-s and Pr = 7.01 Determine/the distance from the entrance at which the velocity boundary layers meet. (Round the final answer to one decimal place.) The distance from the entrance at which the velocity boundary layers meet is m.
Q2: Air at standard conditions of I atm and 27°C flows over a flat plate at 20 m/s. The plate is 60 cm square and is maintained at 97°C. Calculate the heat transfer from the plate. Answers: Q= 681 W,
Air at 10 m/s is flowing over a cylinder of D=(1) cm and L = 1 m. Air has thermalconductivity 0.027 W/mK, kinematic viscosity 1.9*10-5 m2/s, and Prandtl number 0.72.Find the Nusselt number uses charts/table also if needed
Convection H.T. Q3: In an industrial facility, air is to be preheated before entering a furnace by geothermal water at 120°C flowing through the tubes of a tube bank located in a duct. Air enters the duct at 20°C and 1 atm with a mean velocity of 4.5 m/s, and flows over the tubes in normal direction. The outer diameter of the tubes is 1.5 cm, and the tubes are arranged in-line with longitudinal and transverse pitches of SL = Sr = 5 cm. There are 6 rows in the flow direction with 10 tubes in each row. Determine the rate of heat transfer per unit length of the tubes, and the pressure drop across the tube bank. For this square in-line tube bank, if the friction coefficient is 0.16. Also, the correction factor 1 for the square arrangements. Properties: (p = 1.06 kg/m', k =0.02808 W/m °C, u = 2.008x10-5 kg/m.s, Pr = 0.7202 and Cp= 1007 J/kg.K). Take C, = 0.286, C2 = 0.95 and m = 0.608. Ans. q = 23.12 kW, AP = 21 Pa]