摘要:

AbstractThe vortex nozzle, employing the radial pressure differential across a vortex can be effective in limiting the discharge of fluid or slurries from pressurized systems without using small throttling orifices which could plug readily.This paper deals with an investigation of vortex discharge devices which use this principle: It features measurements of velocities using a photographic trace technique. The measured radial distribution of mean tangential velocity departed from a free vortex pattern due to friction losses at the walls of the equipment. Empirical equations were developed for the tangential velocity and the flow, the coefficients being related to parameters of the design.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractAn approximate solution to the equation of motion governing Stokes flow past a number of isolated closed bodies of revolution is obtained by the least squares fitting of a truncated series expression for the stream function to known boundary conditions. The solution yields a reasonably accurate (±5%) estimate for the Stokes resistance on body shapes, such as cylinders and cones, for which analytic solutions are exceedingly difficult. The computed drag values were applied in determining the limitations of the various empirical expressions used to predict the drag resistance of these geometrically simple bodies. A new empirical correlation is presented

ISSN:0008-4034    

DOI:10.1002/cjce.5450510103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractDispersed particles tend to migrate in a preferred direction in a pulsed liquid flow in the presence of fixed baffles of asymmetric design. Conical and inclined disc baffles were found to promote migration of dense materials (sand, hematite) up an inclined length of 5.08 cm. diameter pipe. Conical baffles were effective in increasing the gas holdup in a vertically pulsed bubble column, provided the thick end of the cone was uppermost. These effects are thought to be due to the entrainment of the dispersed phase into separation vortices. Energy dissipation measurements with conical baffles are consistent with this model.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractA formulation is developed and computed results are presented for flow maldistribution in two‐dimensional packed beds involving non‐isothermal systems. Results are shown for both, systems in cylindrical and rectangular coordinates and the examples discussed include the pasage of a two‐dimensional temperature wave through a packed bed of non‐uniform porosity and the examination of the flow maldistribution that is caused by the radial non‐uniformity of temperature.The results indicate that radial temperature profiles in packed beds may lead to flow maldistribution even under conditions where the porosity is uniform and it is suggested that this phenomenon may play an important role in the formation of

ISSN:0008-4034    

DOI:10.1002/cjce.5450510105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractVertical pneumatic conveying was studied in a 3‐inch diameter riser 30 feet in length using solids ranging in particle Reynolds number from 100 to 3500. Particle to gas mass flow ratios varied from 0 to 8 and pipeline conditions extended from dilute flow down into the choking region.Average particle hold‐up was determined by means of a series of quick‐closing valves and particle slip velocity was often found to be greater than the calculated terminal velocity. The reasons for this are examined.Frictional pressure losses in the riser were also determined and compared with literature data. The phenomenon of choking is considered br

ISSN:0008-4034    

DOI:10.1002/cjce.5450510106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractTwo models for vertical pneumatic conveying, a uniform flow model at high gas velocities and an annular flow model near the particle terminal velocity, have been examined theoretically. The uniform flow model leads to the following relationship between gas and particle velocity and line porosity:No simple analytical solution was found for the annular flow model but a numerical solution was possible.Both models indicate that slip velocity may exceed the particle terminal velocity under certain conditions. The theoretical predictions agree reasonably well with experimental observations.\documentclass[article]\pagestyle[empty]\begin[document]$$[\rm v]_[\rm F] = (1 - 2\tau _[\rm F] \\rho _[\rm p] \in [\rm gD]) \in ^[\rm n] + (1 + [\rm Cu]_[\rm T] \in ^[[\rm n] - 1] \[\rm gD])( \in \(1 - \in ))[\rm v]_[\rm p] $$\end[document]

ISSN:0008-4034    

DOI:10.1002/cjce.5450510107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractMomentum‐integral and momentum‐energy‐integral methods are used to study the laminar entrance behaviour of power‐law fluids in annuli. The momentum‐energy method, which yields a longer entry length, appears to provide a better overall description of the entry flow behaviour. The method compares favourably with the existing Newtonian solutions for annular flow and with the non‐Newtonian flow in pipes and parallel plates in the limiting cases. The linearisation technique is also extended to power law fluids utilising the geometric parameter method. The loss coefficients predicted by the linearisation technique agree well with those obtained by the integ

ISSN:0008-4034    

DOI:10.1002/cjce.5450510108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe analysis of the dynamic behavior of a continuous stirred tank reactor with a fluorescent tracer has indicated that the short‐circuit of a fraction of the liquid feed constitutes the only non‐ideality in this case. There is no dead space or piston flow in the reactor when the density difference is zero.The variation of the transfer function time constants was also studied as a first approximation, in a reactor with a density difference between the liquid feed and the reactor contents. This had led to the determination of an ideality criterion which includes the main causes of the non‐ideal mixing. The fluorescent tracer technique has permitted the isolation of the effects of physical parameters on the degree of short‐circuit from the effects on other causes of non‐ide

ISSN:0008-4034    

DOI:10.1002/cjce.5450510109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractVarious physical systems with either phase boundaries or semi‐permeable membranes can give rise to a confined chemical reaction. An analysis was performed to show the strong and potentially important effect of this confined reaction on chemical species diffusion through the region of reaction. The reaction was treated as one near equilibrium in order to obtain an analytical solution and to illustrate the strong coupling of fluxes caused by the reaction. Some generalities, e. g., facilitated diffusion of a single species transferring, were deduced using the above conditions and assumptions. These generalities are necessarily valid only for a single near equilibrium reaction with constant diffusivity of non‐diffusing species. Three examples were solved to illustrate the strong coupling of mass flu

ISSN:0008-4034    

DOI:10.1002/cjce.5450510110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe effects of chemical reactions on wall heat transfer coefficients in packed bed reactors operating at equilibrium or near equilibrium conditions are explored by means of one‐dimensional and two‐dimensional models. Both approaches suggest using Damköhler number or ratios of reacting to frozen heat capacity as parameters in heat transfer correlations. Available data for the methane‐steam reforming reactors were used to establish a suitable correlation for use in thermal design of reacting beds of solids, i. e. NNu= 0.195 NRe0.8exp. (0.21 σ)This correlation can be applied with reasonable accuracy for beds which are 3 to 5‐in. in diameter and bed to particle diameter ratios from 5 to 10. A review of available correlations for wall coefficients obtained under non‐reacting packed bed conditions is als

ISSN:0008-4034    

DOI:10.1002/cjce.5450510111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY