摘要:

AbstractThe importance of real‐fluid behavior during the rapid decompression of dense natural gas mixtures has been investigated using existing one‐dimensional models for real‐fluid isentropic decompression (RID) and perfect‐gas isentropic decompression (PID). The results show that the assumption of perfect‐gas behavior may result in significant errors. In the case of ductile fracture propagation (DFP) analyses, the fracture‐tip pressure level may be underestimated by more than 20 percent.A real‐fluid nonisentropic decompression (RND) model has been developed in order to investigate the importance of nonisentropic effects in DFP problems. The results indicate that nonisentropic effects may be neglected for pipe sizes above approximate

ISSN:0008-4034    

DOI:10.1002/cjce.5450660101

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

年代:1988

数据来源: WILEY

摘要:

AbstractAnalytic expressions for the flow and pressure in a dead‐end duct which has loss of fluid through a porous wall are developed. The presence of an obstruction or auxiliary fan at the end of the duct is included. In either case there is a maximum permissible length of duct. As the duct length approaches this maximum, the main supply fan power and flow increase dramatically.There is no recirculation within the duct when there is an obstruction at the end of the duct. If an auxiliary fan is used, there is always recirculation. However the use of an auxiliary fan can yield major savings in total power requirement

ISSN:0008-4034    

DOI:10.1002/cjce.5450660102

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe gas holdup and gas entrainment of a plunging liquid jet with a gas entrainment guide in an air‐water system was investigated. The measurement of the gas holdup was performed using an over‐flow method. The turbulent jet velocity calculated on an inside nozzle diameter in the range from 4.4‐26.5 m/s for this system has been used in our correlations. The gas holdup has been well correlated in terms of 1/H(v02+ 2gH1),H1d0and the gas entrainment in terms of 1/Hw(v02+ 2gH1),H1,d0. The jet power requirement was also obtained from experimental

ISSN:0008-4034    

DOI:10.1002/cjce.5450660103

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

年代:1988

数据来源: WILEY

摘要:

AbstractSuspension polymerization of styrene was performed using a loop reactor. The dispersing behaviour of the droplets in the course of the reaction was observed. The mean droplet diameter was determined by the energy level at the impeller region. Moreover, the final particle size distribution and mean particle size were also determined after an elapsed time of 1‐2 hrs.An expression which correlated the final mean particle size with the operating conditions, such as the mixing conditions at the impeller region and the initial physical properties of the suspension system, was derived. The deposition of polymers on the reactor wall was found to be prevented due to the high fluid velocit

ISSN:0008-4034    

DOI:10.1002/cjce.5450660104

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

年代:1988

数据来源: WILEY

摘要:

AbstractParticulate fouling tests were carried out using kaolin‐water suspensions flowing through an annular heat exchanger with a copper inner tube. The flow rate was changed from test to test, but the fluid temperature and pH, as well as the particle concentration, were maintained constant.In the lower range of fluid velocities (<0.5 m/s), the deposition process seemed to be controlled by mass transfer. The corresponding experimental transport fluxes were compared to the predictions obtained with several models, showing that diffusion governed particle transport. The absolute values of the mass transfer fluxes and their dependences on the Reynolds number were satisfactorily predicted by some of the model

ISSN:0008-4034    

DOI:10.1002/cjce.5450660105

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe influence of flow velocity and particle size on the deposition of suspended alumina particles onto heat transfer surfaces was measured with two fouling probes, namely, a heated cylindrical rod in an annulus and a coiled wire in crossflow. Additionally, the response of the fouled probes to such changes as may occur in operating heat exchangers was investigated. The measured influence of flow velocity, wall temperature, bulk temperature, heat flux, particle concentration and particle size on the fouling behaviour as described in this paper and in a companion paper is compared to the predictions of several fouling models from the literature, and recommendations are made for further improvement of these models.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660106

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

年代:1988

数据来源: WILEY

摘要:

AbstractDeposition of 0.2 μ haematite (α – Fe2O3) particles from suspension in turbulently flowing water, Reynolds Number = 11000, onto metal tube surfaces has been studied with particular reference to the effect of pH. Measurements on stainless steel showed trivial deposition outside the pH range 5 to 8. Within this range deposition rose sharply to a peak at pH = 6.2. This is similar to the findings of Kuo and Matijevic (1980) who studied haematite particle deposition onto a packed bed of stainless steel beads under laminar flow conditions. This shows that particle/surface interactions govern deposition in this system and that hydrodynamic and geometric factors are second

ISSN:0008-4034    

DOI:10.1002/cjce.5450660107

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

年代:1988

数据来源: WILEY

摘要:

AbstractObjectives of this project were to evaluate benefits — over the short term — that might derive from control of the surface properties of materials used in energy transfer devices; and to identify preferred ranges of surface parameters that might be specified to minimize deposits of biological fouling known to deteriorate energy exchange efficiencies in seawater, brackish water, and freshwater systems. By modifying the surface chemistry and surface energy of test plates with very thin coatings (nontoxic) and examining the acquired films at various time intervals, the earliest events of biofouling caused by macromolecules and microbial organisms were defined. Overall, the results were remarkably similar for all systems tested in showing that deliberate modification of the initial material surface qualities can significantly reduce the retention of biofouling lay

ISSN:0008-4034    

DOI:10.1002/cjce.5450660108

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

年代:1988

数据来源: WILEY

摘要:

AbstractBiofilm adhesion to metals (copper, aluminium and brass) was studied at two different velocities and pH values of 7 and 9. Both bacteria and metals showed negative surface charges at those values of pH, which tends to slow down adhesion. Film densities increased with the fluid velocity and were also affected by the pH and by the growth rate of the bacteria. Long duration tests based on heat transfer measurements were run at five different fluid velocities and at pH = 7, showing in general an asymptotic behaviour and a control of deposition by adhesion and growth phenomena.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660109

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

年代:1988

数据来源: WILEY

摘要:

AbstractIn this study mixed convection heat transfer in ahomogeneous porousduct of square cross section in ahorizontalorientation is examined. Results from a generalizedForchheimermodel are compared with that from theDarcymodel. The heat transfer rate and the flow behavior depend on the following parameters: Grashof number, Gr =Q'gβKa/kv2, an axial flow pressure drop parameter, ζ =(aK/vμ)dp'/dz', an inertial parameter ξ =mK/a, appearing in theForccheimermodel and the Prandtl number, Pr =Cpμ/k.In theDarcylimit, ξ → 0, the role of the axial flow parameter, λ is reduced to a mere scale factor and the flow behavior is determined by a single parameter, λ = Gr · Pr. Both theDarcyand theForchheimermodels exhibit dual solutions and a hysteresis behavior over a certain range of Gr. Such parametric dependence can be used as an additional tool along with carefully designed experiments to determine the importance of inertial and Prandtl number effects on convective heat transfer in po

ISSN:0008-4034    

DOI:10.1002/cjce.5450660110

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

年代:1988

数据来源: WILEY