Calculation of the temperature field in a plane channel with nonuniform heating of thermally conducting walls

A determination is made of the steady temperature of the walls of a channel with Poiseuille gas flow and with heat sources in the thermally conducting walls. The source power density has a parabolic distribution law.     

Laminar heat transfer in a two-dimensional channel with a nonuniform temperature field at the entrance

Heat transfer is investigated, on the basis of the linearized energy equation, in the initial section of a two-dimensional channel with laminar flow of an incompressible fluid and a nonuniform temperature field at the entrance. Results of calculations of the temperature field and Nusselt number Nu are given for various cross sections along the channel.     

Deposition of ultrafine aerosols in a plane channel from a laminar vapor-gas flow of nonuniform concentration

The deposition of a high-dispersity aerosol in a water-vapor concentration gradient field in a thermal diffusion chamber with a control element [1] has been experimentally investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 1, pp. 72–77, January, 1988.     

Thermodiffusiophoretic deposition of highly dispersed particles on the surface of a cylinder

A theoretical study is made of the deposition of particles on the surface of a cylinder. It is shown that the flow of particles being deposited is proportional to the flows of heat and substance passing over the cylinder surface.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 2, pp. 287–291, August, 1985.     

Flow of dilute suspensions of deformable ellipsoidal particles in a plane channel

The influence of the internal properties of deformable suspended particles on the flow of suspensions in plane channels is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No, 4, pp. 560–565, October, 1982.     

Superfluid turbulence in a nonuniform circular channel

We have measured the dissipation associated with superfluid turbulence in a nonuniform channel of circular cross section in order to further explore the discrepancies with theory discovered previously in a nonuniform rectangular channels. Our data show that the two turbulent states supported in uniform circular channels (TI andTII) are also present in our experiments for either diverging or converging flow, indicating that this two-state structure is quite robust. The transition from laminar flow to theTI state and the transition from theTI to theTII state each occur at stationary turbulent fronts in the channel. One consequence of this phenomenon is that theTI/TII transition is substantially broadened. Our data for theTI state, when analysed assuming local uniformity, are in excellent agreement with previous results from uniform channels. The broadenedTI/TII transition severely restricts our experimental access to theTII state. Nevertheless, our data are consistent with the same kind of modification to the vortex line density found for the nonuniform rectangular channels.     

Thermophoretic deposition of aerosol particles in laminar mixed-convection flow in a channel with two heated built-in square cylinders

The thermophoretic deposition of aerosol particles in laminar mixed-convection flow in a channel with two heated built-in square cylinders was studied numerically. The objective of this research was to study the effect of free convection and the distance between cylinders, on deposition of particles. Continuity, momentum and energy equations were solved to determine the velocity and temperature profiles in the channel. The particle trajectories were evaluated by solving the Lagrangian equation of motion that included the drag, Brownian diffusion and thermophoresis forces. It was found that the temperature gradient near the channel wall, in mixed flow regime, is higher than the temperature gradient in forced convection regime. Increasing the temperature gradient increased the effect of thermophoresis on deposition of particles. It was observed that the deposition was increased with the Richardson number. The distance between cylinders is a parameter that influences the deposition of particles. Temperature gradient decreases with increasing the cylinders’ distance; on the other hand, the length of the high temperature gradient zone, which is located in the region between the cylinders where the most deposition occurs, will be increased. These two opposite phenomena cause the fact that at a distance which is four times longer than the cylinders’ length, a maximum cumulative deposition fraction occurs. It was eventually concluded that the thermophoresis and the inertial impaction are dominant deposition mechanisms of particles on the channel wall.     

Forced convection in a plane channel with recesses

An approximate method is suggested for estimating the coefficient of convective heat exchange in fluid flow in a flat channel with rectangular recesses in the walls.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 5, pp. 812–819, November, 1978.     

Times of capture of moderately large nonvolatile aerosol particles by growing or evaporating drops

The time of the total clearing of particles from a given volume around growing or evaporating drops is calculated on the basis of the theory of motion of moderately large nonvolatile aerosol particles in binary gas mixtures which are nonuniform in temperature and concentration.     

Ultrafiltration in a plane channel with one permeable surface

A study is carried out to investigate unsteady-state concentration polarization in the case of laminar ultrafiltration in a plane channel with one permeable surface as a function of the selectivity properties of the membrane.     

Natural convection in a vertical channel in a nonuniform magnetic field

It is shown that a nonuniform magnetic field suppresses the natural convection and shapes the specific MHD flow.Translated from Inzhenerno-Fizicheskii Zhurnal. Vol. 21, No. 3, pp. 510–517, September, 1971.The authors express their sincere thanks to Academician A. V. Lykov for scientific guidance and for constant attention to the work.     

The thermophoretic capture of large volatile aerosol particles by growing or evaporating droplets in multicomponent gas mixtures

The motion of large two-component volatile aerosol particles in a three-component gas mixture containing droplets is considered, which is caused by optical radiation. An expression is derived for the rate of deposition of aerosol particles onto the droplet surface. Analysis is made of the conditions in which the aerosol particles either deposit on the droplet surface or scatter. Numerical estimates are given for antimony-bismuth aerosol particles.     

Condensation enlargement of aerosol particles when a gas mixes with a vapor

From the equations of material and heat balances of the process, functions are obtained for determining the amount of condensate and the diameter of the aerosol particles following the mixing of a gas with a vapor.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 1, pp. 18–22, July, 1985.     

Deposition of aerosol particles in a model vitreous chamber

The purpose of this study was to assess quantitatively the aerosol deposition in a model eye chamber to identify the mechanism(s) of deposition and delivery efficiency for application in retinal disease treated with vitrectomy. Dry aerosol particles were produced with mixtures of fluorescein and a variable concentration of cesium chloride, which ranged in aerodynamic size from 0.6 to 1.3 μm. The aerosol was injected through a small inlet tube into Teflon chambers that had a vented, spherical cavity (diameter ?"). Two filling times of 60 s and 90 s were used. Although significant loss occurred in the syringe, the mass deposited within the chambers increased with aerosol concentration and ranged from 0.5 to nearly 15 μg. Between 60 and 90% of the mass was deposited on the lower surface of the chamber. The mechanism of deposition was consistent with diffusion through a boundary layer during filling followed by sedimentation of the remaining suspended aerosol particles. Based on these results, an aerosol with a median particle size of 1.3 μm was shown to provide a therapeutically effective dose of 5-fluorouracil. The approach is general and can be applied to the aerosol delivery of other drugs to the vitreous chamber.     

Correction to the noise temperature of a waveguide thermal noise generator due to nonuniform heating of the channel

The correction to the noise temperature of waveguide thermal noise generators due to nonuniformity of the heating of the waveguide line is considered. It is shown that, for a simplified model of a thermal noise generator, the minimum values of the corrections in a copper waveguide with dimensions of 2.4×1.2 mm and a waveguide of stainless steel with dimensions of 3.6×1.8 mm amount to 0.05 K and 0.15 K respectively, for a length of the nonuniformly heated part of the waveguide line of 80 mm. Translated from Izmeritel'naya Tekhnika No. 5, pp. 46–49, May, 1998.     

Concentrational polarization in ultrafiltration in a plane channel

We investigated steady-state concentrational polarization in laminar ultrafiltration in a plane channel in relation to the selective properties of the membrane.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute of the Academy of Sciences of Belarus, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 3–4, pp. 235–239, September–October, 1994.     

Acceleration of solid particles in a channel

On the basis of an anlaysis of the distribution of the parameter of a two-phase flow emerging from a channel we obtain a criterial relation for the velocity disequilibrium of the phases.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 8, No. 1, pp. 16–20, January, 1990.     

Thermal polarization of a viscous gas flow accompanied by slip in a channel with a nonuniform surface

A theoretical model of heat transfer is proposed and measurements are made of the temperature field in a gas flow in an isothermal channel with a nonuniform surface.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 4, pp. 566–571, October, 1988.     

Development of liquid flow in a plane channel with moving permeable walls

We determined the laws that govern the change in hydraulic resistance in viscous incompressible liquid flow between parallel permeable and moving walls. The laws are of great practical interest. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No.2, pp. 200–204, March–April, 1997.