For flow over a flat plate of length L, the local heat transfer coefficient
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Fundamentals of Heat and Mass Transfer
- An average man has abody surface area of 1.8m2 and a skin temperature of 33degrees celcius .The convection heat transfer coefficient for a clothed person walking in still air is expressed as {h,8.6V^0.53}FOR 0.5<v<2m/s,where V is the walking velocityin m/s.Assuming the average surface temperature of the clothed person to be 30degrees celcius, determine the rate of heat loss from an average man walking in still air at 10degrees celcius by convectionat a walking velocity of (a)0.5m/s (b)1.0m/s (c)1.5m/s (d)2.0m/sarrow_forwardEngine Oil at 58.95 degrees celsius Flows over a 5m long flat plate whose temperature is 20.11 degrees celsius with a velocity of 2.2m/s. Determine the rate of heat transfer (W), considering forced convection, per unit width of the entire plate. Density = 876kg/m^3 Thermal conductivity = 0.144W/m-K Pr = 2870 dynamic viscosity = 0.21kg/m-s Q = ?arrow_forwardWater 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 procesarrow_forward
- Q.1) Determine the convection heat transfer coefficient and the heat flux on the plate surface for flow of air at T = 20° C over a plate surface maintained at a constant temperature of T₁ = 160° C. if the dimensionless temperature profile within the air layer = e-ay, where a = 3200 m ¹ and y is the vertical over the plate is determined to be T(y)-Too Ts-Too distance measured from the plate surface in m.arrow_forwardWhat is the rate of heat loss through a 4-cm Fiberglass wall of the inside temperature is 22 °C and the outside temperature is 45 °C and windy (17 kph) ? the area of the wall is 100 square meters. Include surface films. Assume the k-value for 4-cm fiberglass is 0.056 W/m. °C and the surface air film coefficient for windy velocity (17 kph) is 0.053 for out film and the inner film Rs value is 0.093 as per the surface film coefficient tables ?arrow_forwardQ1: In a process water at 30°C flows over a plate maintained at 10 °C with a free stream velocity of 0.3 m/s. Determine the hydrodynamics boundary layer thickness, thermal boundary layer thickness, local and average values of heat transfer coefficient and refrigeration necessary to maintain the plate temperature. Consider a plate of 1m x 1m size. At the film temperature the property values are: Kinematic viscosity 1.006 x 106 m²/s, Thermal conductivity =0.5978 W/m.K, Prandtl number=7.02. =arrow_forward
- Oil is flowing through a 50 mm-ID and 55 mm-OD pure iron pipe at 1 m/s. It is being heated by steam outside the pipe and steam film coefficient may be taken as 11 kW/m2°C. At a particular point along the pipe, the oil is at 50°C, its density is 880 kg/m³, its viscosity is 2.1 cP, its thermal conductivity is 0.135 W/m°C and its specific heat is 2.17 J/g°C. What is the overall heat transfer coefficient at this point, based on the inside area of the pipe? If the steam temperature is 130°C, what is the heat flux at this point, based on the outside area of the pipe?arrow_forwardHeat Transferarrow_forwardWhat’s the correct answer for this please ?arrow_forward
- Water flows in a 3.5-cm-diameter pipe so that the Reynolds number based on diameter is 2000 (laminar flow is assumed). The average bulk temperature is 10°C. What would the heat transfer coefficient be in W/m2.°C for such a system if the tube wall was subjected to a constant heat flux and the velocity and temperature profiles were completely developed? Evaluate properties at bulk temperature.arrow_forwardFor a water flow over a steel surface, the temperature of water at a specific location was found to change with the vertical distance from the surface (y) up to a distance of 0.015 m as T(y) = 60 + 20y + tan(y), where temperature is in °C and y is in cm. The surface temperature and ambient temperature was measured as 60°C and 105°C, respectively. The thermal conductivity of steel and water are, respectively, 48 W/m-K and 0.6 W/m-K. What is the local convection coefficient at this location?arrow_forwardIn convection heat transfer, what happens to the heat transfer coefficient if the viscosity of the fluid decreases? Select the correct response: The heat transfer coefficient remains constant The heat transfer coefficient also increases The heat transfer coefficient partially increases then decreases The heat transfer coefficient will decreasesarrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning