Estimate the interfacial heat transfer coefficient for evaporation of a thin film ofsaturated liquid water at atmospheric pressure. The liquid film rests on a flat, solidsurface to which a constant and uniform heat flux of 150 kW/m? is applied. Theaccommodation coefficient may be taken to be 0.05. If the liquid film thickness is 0.2mm, compare the interfacial vaporization resistance with the conduction resistancethrough the liquid film.

Conduction Resistance of Interfacial Vaporization, RA = Heat FluxCoefficient Value=1500.05=3000 = 3…

Estimate the interfacial heat transfer coefficient for evaporation of a thin film of saturated liquid water at atmospheric pressure. The liquid film rests on a flat, solid surface to which a constant and uniform heat flux of 150 kW/m² is applied. The accommodation coefficient may be taken to be 0.05. If the liquid film thickness is 0.2 mm, compare the interfacial vaporization resistance with the conduction resistance through the liquid film.

Estimate the interfacial heat transfer coefficient for evaporation of a thin film of saturated liquid water at atmospheric pressure. The liquid film rests on a flat, solid surface to which a constant and uniform heat flux of 150 kW/m² is applied. The accommodation coefficient may be taken to be 0.05. If the liquid film thickness is 0.2 mm, compare the interfacial vaporization resistance with the conduction resistance through the liquid film.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A horizontal pipe of 100-mm-diamter and 1 m long with a surface temperature of 94 ℃ is used to condense saturated steam at 1 atm. Determine the heat transfer rate for the condensation process. Properties of Water, vapor (1 atm): Tsat = 100℃, ρv = 0.596 kg/m3, hfg = 2257 kJ/kg;Water, liquid (Tf = 370K): ρl = 960.6 kg/m3, Cpl = 4214 J/kg.K, μl = 289*10^-6 N.s/m2, kl = 0.679 W/m.K. Select one: a. 28567 W b. 18254 W c. 19076 W d. 22552 W
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.
A- Cylinder has a 0.1m in length and 0.1min diameter, is initially at 292 K. It is suspended in a steam environment where water vapor at 373 K condenses on all surfaces with an effective film coefficient, h, of 8500W/m2 K. Determine the time required for the center of this stubby cylinder to reach 310 K. If the cylinder were sufficiently long so that it could be considered infinite, how long would it take? (4 Marks)
You have a 2 mm thick layer of water on the floor of a room. The water vaporizes and diffuses through a stagnant film of air, estimated to be 2.5 mm thick, on the surface of the water. Under the evaporation condition, consider as an approximation that the temperature of the water is essentially equal to its dry bulb temperature, 28 ° C. Calculate the time required for the water layer to completely disappear, for thecase the floor is porous and the water also penetrates the floor at a constant rate of 0.1kg / (m2.h).Calculate the vapor pressure of water using the Antoine equation below. The diffusivity of water vapor in air is 0.2201 cm2 / s at 1 atm and 0 ° C. The vapor pressure, P ° (in bar), of the water is given by: ln (P °) = 13.8573 - 5160.2 / T, where T is the temperature in K.
Air is to be heated by passing it across the tubes of an in-line tube bundle consisting of 8 rows of 25 mm OD tubes in the direction of flow and 10 tubes in each row normal to the flow. Air approaches the tube bank in the normal direction at 30 °C and 1 atm with a mean velocity of 10 m/s. The tube spacing is 37.5 mm in both parallel and normal to the flow. Calculate the heat transfer from the bundle per m of length when the tube surface temperature is 90 °C.
Compare the capillary effect of immersion in (i) water and (ii) mercury of a glass tube of 6 mm internal diameter. The surface tension values are 0.072500 N/m and 0.60 N/m for water and mercury. The angle of contact for water is zero degree. The angle of contact for mercury is 130°
Calculate the capillary effect in mm in a glass tube of 2mm diameter, when immersed in (1)water, (2)mercury. The temperature of the liquid is 25°C and the values of surface tensions of water and mercury at 25°C in contact with air is 0.0755 and 0.52N/m respectively. The angle of contact for water is 0° and 130° for mercury. Take the density of water 1000 kg/m³, specific gravity of mercury is 13.6. (ENTER ONLY THE VALUES BY REFERRING THE UNITS GIVEN) The capillary effect of water in mm is equal to= The capillary effect of mercury in mm is equal to=
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
A 2 m wide, 3 m high, and 50 mm thick sheet of XPS insulation (M = 50 ng/Pa.s.m2), has a vapor pressure of 1500 Pa on one side, and 3500 Pa on the other. Calculate the vapor flow rate (Qv), vapor flux (qv), permeability, Rv value and the permeability (μ)
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?
A copper rod of 30 kg initially at the temperature of 300 °C needs to be immersed and fitted tightly into a ABA alloy ring with inner diameter 30.0015 mm found in tank of 100 liters water of 25 °C. (i) Determine the diameter copper when it is 300 °C. (ii) In your opinion, does the copper rod will still fit tightly into the ABA alloy ring inner diameter 30.0015 in the ambient air condition of 25 °C. Provide your answer in 4 decimal places. Assume the alloy ABA is very small with negligible effect in heat transfer. [Density for copper = 8890 kg/m3, Specific heat, Ccopper = 385 J/kg.°C;Coefficient of thermal expansion, αCopper = 18.0 × 10-6 (°C)-1]. [Density for ABA alloy = 8500 kg/m3, Specific heat, CABA = 138 J/kg.°C;Coefficient of thermal expansion, αABA = 13.3 × 10-6 (°C)-1]. [Density for water = 1000 kg/m3, Specific heat, Cwater = 4200 J/kg.°C].
Water at 25 °C is flowing at a velocity of 0.45 m/s in a tube having a mass transferarea (Black region in the figure) of 4.42.10-5 m2. The tube is 1.2 m long with the walls coatedwith formic acid. The solubility of formic acid in water is 100000 mg/L. Viscosity of water is8.71 x 10-4 Pa.s and the density of water is 996 kg/m3. Assuming that the velocity profile is fullydeveloped.a. Determine the flow type.b. Calculate the convective mass-transfer coefficient k'c.c. Calculate the flux of NA.