Topic
Mass transfer coefficient
About: Mass transfer coefficient is a research topic. Over the lifetime, 7827 publications have been published within this topic receiving 168354 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: The mass transfer coefficient in covered, right-cylindrical tanks full of liquid, turbulently agitated at various speeds by turbines with six flat blades, was measured by the rate of solution suspended solids in water and in 45% sucrose solutions.
Abstract: The mass transfer coefficient in covered, right-cylindrical tanks full of liquid, turbulently agitated at various speeds by turbines with six flat blades, was measured by the rate of solution suspended solids in water and in 45% sucrose solutions.
Screened crystals in the following U. S. mesh sizes were used: boric acid: 18/20, 16/18, 16/20, 14/16, 12/14, 10/12, 8/10, 6/8; rock salt: 6/8, 4/6. Pellets were benzoic acid: 0.126 in. long by 0.218-in. diam.; salt: 0.565-in. diam. by 0.531-in. long (over rounded ends). Tanks were 6, 12, 18, and 30 in. Turbines were 2, 3, 4, 6, 9, and 12 in. in diameter, centrally located. Four full-length baffles 10% of the tank diameter wide were spaced at 90 deg. A few runs were made without baffles.
The coefficient of mass transfer was found to be independent of particle size and Schmidt member (NSc = 735 to 62,000) and could be correlated with turbine Reynolds number in each tank, with larger tanks yielding smaller coefficients at the same NRe. An empirical equation which fits all the data from the baffled tanks within about 4% (in the range 0.1 < k < 2) is
where l2=0.8235−1.544V1/3+0.115V2/3The variance of estimate for this expression i s 0.0383, in units of [ln(10 k)]2.For extrapolation outside the experimental range of vessel sizes it is recommended that l1 = 0.676 − 1.266 V1/3 be used in place of I2. NRe = T2n/v. The results indicate that power per unit volume for a given k goes through a maximum, with the following relative values for the 6-, 12-, 18- and 30-in. tanks: 1, 1.73, 1.78, 0.62.A treatment of the data according to dimensionless groups provides another correlation:kd/D=0.02NNt is shown that for the systems used 1/D is essentially proportional to N, and so the effect of diffusivity here is only apparent.
67 citations
TL;DR: An approach for estimating the mass transfer coefficient (h) of fumigant compounds across agricultural films is presented and it is shown that the method produces a sensitive and reproducible measure of film permeability.
Abstract: Plastic tarps currently used during soil fumigation to control emissions have been shown to be permeable to fumigant vapors, resulting in appreciable losses to the atmosphere. New low-permeability films are being developed to reduce fumigant emissions and increase efficacy. A rapid, reliable, and sensitive method is required to measure the permeability of various films that may be used in new management practices. This manuscript presents an approach for estimating the mass transfer coefficient (h) of fumigant compounds across agricultural films. The h is a measure of the resistance to diffusion which, unlike other measures of permeability, is a property of the film-chemical combination and independent of the concentration gradient across the film. This method uses static sealed cells; fumigant vapor is spiked to one side of the film and the concentrations on both sides of the film are monitored until equilibrium. An analytical model is fitted to the data to obtain h. This model relies on a mass balance approach and includes sorption to and diffusion across the film membrane. The method was tested using two polyethylene films and a very low-permeability film and showed that the method produces a sensitive and reproducible measure of film permeability.
67 citations
TL;DR: In this paper, the effects of viscous dissipation and second order slip on MHD boundary layer flow of an incompressible, electrically conducting water-based nanofluid over a stretching sheet were investigated.
Abstract: In this study, we investigate the effects of viscous dissipation and second order slip on MHD boundary layer flow of an incompressible, electrically conducting water-based nanofluid over a stretching sheet. The governing momentum boundary layer and thermal boundary layer equations with the boundary conditions are transformed into a system of nonlinear ordinary differential equations which are then solved numerically by using the Runge–Kutta–Fehlberg method. The effects of the flow parameters on the velocity, temperature, nanoparticle concentration, shearing stress, rate of heat transfer, and rate of mass transfer are analyzed, and illustrations are provided by the inclusion of figures and tables for various values of different parameters. We determine that the skin friction increases in magnitude, whereas the rate of heat transfer and rate of mass transfer decrease in magnitude as the strength of the magnetic field increases. In addition, the magnitudes of skin friction, rate of heat transfer, and rate of mass transfer decrease as the melting heat transfer and first-order slip parameter both increase.
67 citations
TL;DR: The theory for the rate of mass transfer through a long tube connecting two reservoirs of constant concentration with oscillatory flow in the tube is developed in this article, where the increase in transfer rate relative to that due to molecular diffusion alone is found as a function of three dimensionless groups, an oscillatory Reynolds number ωa2/v, an amplitude parameter A/a and the Schmidt number v/D.
66 citations
TL;DR: In this article, a comprehensive review of empirical correlations for the determination of mass transfer coefficient and moisture effectiveness in both adiabatic and internal cooling/heating dehumidifier/regenerators is presented.
66 citations