摘要:

AbstractThis paper presents an analytical method for calculating the flow and pressure in A dead‐end duct which has a perforated, porous barrier and an auxiliary fan or an obstacle at the end of the duct. The solutions involve two infinite series which can be applied to a general class of differential equations. It is shown that the duct length may be bounded if the barrier is porous only. No such bound exists if there are holes in the barrier. There is a minimum in the flowrate through the duct when there is a fan at the dead end. No such minimum exists when there is an obstac

ISSN:0008-4034    

DOI:10.1002/cjce.5450660401

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

年代:1988

数据来源: WILEY

摘要:

AbstractA simple method has been developed for modelling the recovery of bitumen from packed beds of oil sand by water or caustic solution displacement. Batches of reconstituted oil sand were prepared by intimately mixing predetermined amounts of sand, water, and bitumen, thereby permitting the composition of the oil sand to be controlled and varied within a wide range. Dilution of the bitumen with hexadecane facilitated the mixing process and allowed experiments to be performed at low temperatures while maintaining oil‐water viscosity ratios comparable to those prevailing at the higher temperatures encountered during hot water or steam displacements in the field. The effects of a wide range of compositional and operational variables were studied using a two‐level fractional factorial design technique and the findings are discussed. Of particular interest are the observations that the density and initial connate water saturation of the oil sand exert significantly more effect on bitumen recovery efficiency for the case of water displacement than for caustic solution displacem

ISSN:0008-4034    

DOI:10.1002/cjce.5450660402

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

年代:1988

数据来源: WILEY

摘要:

AbstractAn alternative correlation for the flow of purely viscous non‐Newtonian fluids in ducts of arbitrary cross‐section is proposed. It involves two dimensionless groups which are\documentclass{article}\pagestyle{empty}\begin{document}$$\phi = \frac{{\tau \,_w \rho D^2 }}{{\eta _w^2 }}$$\end{document}Unique relationships exist between ϕ and Re*Gfor both laminar and turbulent flows which enable direct predictions of pressure drop from flow rate results or vice‐versa. Excellent agreement between the new correlations and available experimental data for purely viscous non‐Newtonian fluids flowing in circular tubes and square ducts is demo

ISSN:0008-4034    

DOI:10.1002/cjce.5450660403

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

年代:1988

数据来源: WILEY

摘要:

AbstractLaminar friction loss and heat transfer characteristics for a non‐Newtonian fluid described by a general viscosity function of the structural type have been computed for tube and slit geometries. The model includes most other models for fluids without a yield stress as special cases. The Graetz problem for constant wall temperature and temperature independent properties has been solved, including viscous dissipation, for the transverse and axial temperature distribution. Both momentum and energy transport characteristics are shown to be strongly dependent upon a dimensionless fluid time constant, which characterizes the transition from Newtonian to non‐Newtonian shear thinning behavior. A direct and exact analogy between the momentum and energy transport mechanisms is demonstrated for hydrodynamically and thermally fully developed flow, provided the heat transfer rate is represented by a suitably defined Nusselt num

ISSN:0008-4034    

DOI:10.1002/cjce.5450660404

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe design of heat exchangers which resist fouling is examined. It is shown that for asymptotic reaction fouling in a uniform wall temperature exchanger with outlet fluid temperature kept constant, it is possible to obtain an optimum combination of exchanger size and tube‐side temperature. This optimum minimises the amount of fouling in the system. An equation which gives a good approximation to the optimum is derived, and its limitations discusse

ISSN:0008-4034    

DOI:10.1002/cjce.5450660405

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

年代:1988

数据来源: WILEY

摘要:

AbstractEnd wall effects on thermal stratification and heat transfer in a vertical enclosure with offset partitions has been studied by numerically solving the governing differential equations. Two limiting end wall conditions are investigated — adiabatic end walls and perfectly conducting end walls. Two offset partition positions and three partition heights are considered. It is observed that with adiabatic end walls, the heat transfer from the vertical hot and cold walls is always greater. The effect of end wall conditions is most significant when the top partition is offset toward the cold wall and the bottom partition toward the hot wall. In this position strong thermal stratification in the core is observed. When the direction of offset is reversed, i.e., top partition is moved closer to the hot wall and the bottom partition closer to the cold wall, strong stratification effects are noted in the partition‐near side wall region. Adiabatic end wall conditions promote these stratification effe

ISSN:0008-4034    

DOI:10.1002/cjce.5450660406

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

年代:1988

数据来源: WILEY

摘要:

AbstractParticle‐liquid mass transfer in a three phase sparged reactor has been studied over a wide range of particle sizes, for the chum‐turbulent regime. The particle‐liquid Sherwood number has been correlated in the usual form with the Reynolds and Schmidt numbers. Use of the hindered particle settling velocity in the Reynolds number yields good agreement (±20%) with the present as well as most of the literature data. The proposed correlation also holds for power law non‐Newtonian liquids when the effective viscosity

ISSN:0008-4034    

DOI:10.1002/cjce.5450660407

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

年代:1988

数据来源: WILEY

摘要:

AbstractA simple method has been developed to optimally design a distillation sequence with a fixed degree of flexibility in feed composition and flowrate, and accounts for uncertainty in stage efficiency,K‐value and beat transfer coefficient calculations. The method minimizes a weighted cost function and ensures both optimal and feasible operation in the range of flexibility/uncertainty by using an approach termed “practical feasibility”. The method was tested on a 4 column distillation sequence separating a 5 component light alkane feed mixture. Results are presented to illustrate the effect of uncertainty on sequence cost and column overd

ISSN:0008-4034    

DOI:10.1002/cjce.5450660408

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

年代:1988

数据来源: WILEY

摘要:

AbstractGeneral strategies for solving the problem of computing the equilibrium composition of a multiphase, multispecies, chemically reacting system are discussed. An efficient new algorithm is presented based on these strategies, together with a microcomputer‐based implementation. Numerical examples show the algorithm's utility, and its advantages over other recently proposed methods in terns of a number of criteria, including speed and certainty of convergence. The range of problem types within the capability of the new algorithm, and its limitations are discusse

ISSN:0008-4034    

DOI:10.1002/cjce.5450660409

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

年代:1988

数据来源: WILEY

摘要:

AbstractA problem of gas absorption with a fast nonisothermal bimolecular reaction in a thin liquid film has been analysed. Approximate analytical solutions for the interfacial temperature rise and enhancement factor have been derived incorporating the influence of depletion of liquid reactant concentration at the interface. The effects of heat generation, heat dissipation and reaction rate parameters on enhancement factor and interfacial temperature rise have been discussed. For a certain range of parameters, multiple steady state solutions of enhancement factor and interfacial temperature rise are observed. Another interesting observation is that as the value of a dimensionless parameter ϕ increases, the enhancement factor approaches its instantaneous asymptote which is the same as that for the isothermal case in an instantaneous regime. The analysis presented here is simple and avoids complex numerical computations and it is likely to be useful in design applications

ISSN:0008-4034    

DOI:10.1002/cjce.5450660410

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

年代:1988

数据来源: WILEY