Mass transfer circular cylinder

Wiebelt J.A., Ruo S.Y. (1963) Radiant-interchange configuration factors for finite right circular cylinder to rectangular plane. International Journal of Heat Mass Transfer 6, 143-146. 

J. Schmid, Longitudinal laminar flow in an array of circular cylinders, nt. J. Heat Mass Transfer 9 925 (1966). 

Sparrow, E.M. Abraham, J.P. Tong, J.C.K. Archival correlations for average heat transfer coefficients for non-circular and circular cylinders and for spheres in cross flow. Int. J. Heat Mass Transfer 47 (2004) 5285-5296... 

Mass transfer between a circular cylinder of radius a and a simple shear flow (G 2 = 1, the other Gkm = 0) was studied in [132]. For the dimensionless total diffusion flux per unit length of the cylinder, the following expression was obtained as Pe 0 ... 

Let us consider diffusion to the surface of a circular cylinder of radius a in a flow with velocity Ui directed along the normal to the cylinder axis. This is a model problem used in chemical engineering for calculating mass transfer to prolate particles it is used even more widely in mechanics of aerosols for analyzing diffusion sedimentation of aerosols on fibrous filters [139,461]. 

The solution of the corresponding mass exchange problem for a circular cylinder and an arbitrary shear flow was obtained in [353] in the diffusion boundary layer approximation. It was shown that an increase in the absolute value of the angular velocity Cl of the shear flow results in a small decrease in the intensity of mass and heat transfer between the cylinder and the ambient... 

Freely rotating cylinder. Now let us consider convective mass transfer to the surface of a circular cylinder freely suspended in an arbitrary linear shear Stokes flow (Re -> 0). In view of the no-slip condition, the cylinder rotates at a constant angular velocity equal to the angular velocity of the flow at infinity. The fluid velocity distribution is described by formulas (2.7.11). The streamline pattern qualitatively differs from that for the case of a fixed cylinder. For 0 0, there are no stagnation points on the surface of the cylinder and there exist two qualitatively different types of flow. For 0 < Ifigl < 1, there are both closed and open streamlines in the flow, the region filled with closed streamlines is adjacent to the surface of the cylinder, and streamlines far from the cylinder are open (Figure 2.11). For Ifl l > 1, all streamlines are open. 

In the mass exchange problem for a circular cylinder freely suspended in linear shear flow, no diffusion boundary layer is formed as Pe - oo near the surface of the cylinder. The concentration distribution is sought in the form of a regular asymptotic expansion (4.8.12) in negative powers of the Peclet number. The mean Sherwood number remains finite as Pe - oo. This is due to the fact that mass and heat transfer to the cylinder is blocked by the region of closed circulation. As a result, mass and heat transfer to the surface is mainly determined by molecular diffusion in the direction orthogonal to the streamlines. In this case, the concentration is constant on each streamline (but is different on different streamlines). 

L. M. De Socio, Laminar Free Convection Around Horizontal Circular Cylinders, Int. J. Heat Mass Transfer (26) 1669-1677,1983. 

In typical applications, pure solid naphthalene is melted and poured into a mold so it will have the desired shape such as a flat plate [127], a circular cylinder [128], or a turbine blade [129]. For average mass transfer measurements on a test surface, the section coated with naphthalene can be weighed before and after exposure to air flow to determine the mass transfer rate. Local mass transfer coefficients can be determined from the sublimation depth, which is the difference in surface profiles, measured using a profilometer, before and after each test run. Once the vapor density of naphthalene is known, the local mass transfer coefficient hD can be evaluated from the following expression ... 

The calculated rate of sublimation is an instantaneous value. Mass transfer will rapidly reduce the cylinder diameter, so that Re and hence Fav will change with time. Furthermore, the surface will not remain in the form of a circular cylinder, owing to the variation of the local F about the perimeter, so that the correlation for Nu0l, and Shav will no longer apply. 

Estimate convective mass-transfer coefficients for the following situations (a) flow paralell to a flat surface, (b) flow past a single sphere, (c) flow normal to a single cylinder, (d) turbulent flow in circular pipes, (e) flow through packed and fluidized beds, and (f) flow through the shell side of a hollow-fiber membrane module. 

McDaniel, C. S., Webb, B. W, 2000. Slot jet impingement heat transfer from circular cylinders. Int.J. Heat Mass Transfer 42 1975-1985. 

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