● Problem 1 • Air at 40 oC and 1 atm flows over a 5 m long wet plate with an average velocity of 2 m/s to dry the surface. Using analogy between heat and mass transfer. Determine the mass transfer coefficient on the plate. · Extra information: at 40 oC and 1 atm, v= 1.702 *10-5 T2.072 ● DAB 1.87 x 10-5 x P

● Problem 1 • Air at 40 oC and 1 atm flows over a 5 m long wet plate with an average velocity of 2 m/s to dry the surface. Using analogy between heat and mass transfer. Determine the mass transfer coefficient on the plate. · Extra information: at 40 oC and 1 atm, v= 1.702 *10-5 T2.072 ● DAB 1.87 x 10-5 x P

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.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.34P

See similar textbooks

Similar questions

In a falling-film evaporator, Air at 40℃ and 50 kPa flows through a wetted-wall column with 100 mm diameter at a velocity of 5 m/s. What is the mass-transfer coefficient for the humidification of this stream by evaporation from the wet walls? If the air in this situation is 50 % saturated, and the saturation particle pressure of water vapour at 40℃ is 7375 Pa, what is the local evaporation flux in a unit of kg/m²s?
Air at 20°C and 1 atm flows through a cylindrical tube made of naphthalene at a velocity of 5 m/s. The diameter of the tube is 0.1 m. Using the correlations, calculate the mass transfer coefficient for this setup. Then, compare this result with the mass transfer coefficient from the Reynolds Analogy, Prandtl Analogy, Von Karman Analogy, and Chilton-Colburn Analogy. The effectivity diffusivity is 4.24 x 10-6 m2/s.
● Air at 40 oC and 1 atm flows over a 5 m long wet plate with an average velocity of 2 m/s to dry the surface. Using analogy between heat and mass transfer. Determine the mass transfer coefficient on the plate. • Extra information: at 40 oC and 1 atm, v= 1.702 *10-5 T2.072 DAB 1.87 x 10-5 x P
From an open water surface with air temperature 22°C, relative humidity is 40% and wind speed is 3 m/s, all measured at height 2 m above the water surface. Assume a roughness height of 0.03 cm. The net radiation is 200 W/m^2. Cp = 1005 J/kg-K A. Calculate the latent heat of vaporization (J/kg) B. Calculate the evaporation using Energy Balance Method (mm/day) C. Calculate the saturation deficit of the vapor pressure (Pa) D. Calculate the evaporation using Priestley-Taylor Method (mm/day)
Use the definition of the Sherwood number to calculate the mass transfer coefficient (in cm/s) for a scenario where the characteristic length is 0.034 m, the diffusivity is 0.00099 cm^2/s, and the Sherwood number is 3.5.
Wet sawdust will be dried using air on a circular tray with a diameter of 10 cm and the variation of moisture content over time will be examined. The heat transfer coefficient was calculated as 0.64 cal/min.cm2.°C and the mass transfer coefficient as 3.86 g/cm2.min during the constant speed drying interval lasting 10 minutes. Calculate the dry bulb temperature since the absolute humidity of the air used for drying is 0.018 g water/g dry matter and the wet bulb temperature is 25°C. Additional data: Enthalpy of evaporation of water: 2442.3 kj/kg at 25°C Vapor pressure of water: 23.76 mm Hg at 25°C
Q3/Condensing steam at 1 atm is used to maintain a vertical plate 20 cm high and 3.0 m wide at a constant temperature of 100°C. The plate is exposed to room air at 20°C. What flow rate of air will result from this heating process? What is the total heating supplied to the room air? Ans. 0.0034 kg/s, 278W
Humid air at constant 101 kPa pressure, 30°C temperature and 40% relative humidity undergoes an isobaric cooling process unitl its temperature reaches 22°C. Calculate how much energy by heat is transferred from the air stream in kJ per kg of dry air. Give you answer to two significant figures and enter the numerical value only (eg. 0.0123, 0.123., 123, 1230, but not 0.0123 kJ/KGDA). 3
Incident radiation at the Laguna Lake is 985 W/m2 at noon on February 14th. Water temperature is 27.5 °C. Air temperature is 28.0°C, relative humidity is 75%, and wind speed is 1.7 m/s at 2m. - Determine the open water evaporation rate in mm/d using the energy method
The sensible heat-transfer coefficient for a dry surface has been determined to be 50 W/(m2-C) at a certain Reynolds number. Estimate the total heat transfer to the surface per unit area at a location where the wall temperature is 10 C and the state of the moist air flowing over the surface is given by 24 C dry bulb and 18 C wet bulb. Assume that the Reynolds number does not change and the Lewis number is 0.82. Assume that the condensate present on the surface will increase the transfer coefficients by about 15 percent.
The defroster of an automobile functions by discharging warm air on the inner surface of the windshield. To prevent condensation of water vapor on the surface, the temperature of the air and the surface convection coefficient (T¡,¡ ) must be large enough to maintain a surface temperature T, that is at least as high as the dewpoint (Ts,i ≥ Tdp). Step 1 00,0¹ kg 8 - 0 Consider a windshield of length L = 800 mm and thickness t = 6 mm and driving conditions for which the vehicle moves at a velocity of V = 70 mph in ambient air at T%0,0 = 0°C. From laboratory experiments performed on a model of the vehicle, the average convection coefficient on the outer surface of the windshield is known to be correlated by an expression of the form 1/3 Nu₁ = 0.037 Re8 Pr¹/³, where Re₁ = VL/v. Air properties may be approximated as k = 0.023 W/m·K, v = 12.5 × 10-6 m²/s, and Pr = 0.71. If Tdp = = 10°C and Ti 50°C, what is the smallest value of the inside convection coefficient required to prevent…
Humid air at constant 101 kPa pressure, 30°C temperature and 40% relative humidity undergoes an isobaric cooling process unitl its temperature reaches 22°C. Calculate how much energy by heat is transferred from the air stream in kJ per kg of dry air. Give you answer to two significant figures and enter the numerical value only (@.g. 0.0123, 0.123, 123, 1230, but not 0.0123 kJ/kgDA).