摘要:

AbstractAn apparatus, devised to measure the viscosities of relatively viscous liquids, is described. The device involves the motion of a sphere oscillated forcibly in the liquid with the help of an external driving mechanism. A theoretical analysis shows that the frequency and the amplitude of forced oscillation are independent of the density of the liquid and are solely determined by the viscosity for very viscons liquids. When the viscosity is sufficiently high, a completely developed laminar flow may be assumed at all stages of the motion. Under these conditions, the peak amplitude for resonance is suggested as a direct measure of viscosity.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490301

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

年代:1971

数据来源: WILEY

摘要:

AbstractTwo sizes of particles of 500μ and 100μ mean diameter were conveyed as water slurries through 1 inch and 2 inch horizontal pipelines. Pressure drops and saltation velocities were measured over a range of slurry concentrations to 14% by volume with and without concurrently flowing air. In the former case, the principal flow patterns studied were in the bubble and plug flow regimes. Although small effects on saltation point were noted due to the induced turbulence from the air bubbles, these were not significant, and a reasonable estimate of saltation velocities could be made from Durand's correlation. Pressure drops were found to be correlated reasonably well by modified Lockhart‐Martinelli parameters as used for turbulent‐turbulent horizontal gas‐liquid flow except at conditions near the saltation point. Pressure drops for slurry flow alone were predicted reasonably well by the modified Durand e

ISSN:0008-4034    

DOI:10.1002/cjce.5450490302

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe sound accompanying nucleate and film boiling on a platinum wire immersed in a water pool at atmosphere pressure is related to the rate of heat transfer from the wire surface. In particular the total sound intensity is shown to be a function of the heat transfer resulting from bubble evolution. Analysis of the acoustic spectra for saturated and sub‐cooled boiling shows how the level of selected components varies with changes in the heat flux and liquid temperature.The possibility of using an acoustic detection device to detect boiling caused by channel blockage in a liquid cooled system is discusse

ISSN:0008-4034    

DOI:10.1002/cjce.5450490303

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

年代:1971

数据来源: WILEY

摘要:

AbstractA model of a fibrous bed coalescer is presented which relates the collision frequency between particles and fibers to the overall coalescence frequency. The model will predict the ratio of outlet to inlet particle number densities (Y) and takes into account the mean inlet particle size, mean fiber size, void fraction of the bed, superficial velocity through the bed, degree of bed saturation, and bed length. The ratio of outlet to inlet particle number density, in terms of these parameters, is given by\documentclass{article}\pagestyle{empty}\begin{document} \[Y = \exp \left\{{- \frac{{3(1 - \in)S(1 + d_{10} /d_f)}} {{4d_f (1 - S)}}\eta _e L} \right\} \] \end{document}where η is defined as the coalescence efficiency and varies between 0 and 1 with the fiber Reynolds number

ISSN:0008-4034    

DOI:10.1002/cjce.5450490304

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

年代:1971

数据来源: WILEY

摘要:

AbstractA model of a fibrous bed relating the ratio of the outlet and inlet particle number densities to the various system parameters is tested experimentally. The degree of bed saturation is also determined from single phase and two phase flow data. The inlet and outlet particle number densities are determined by light scattering. It was found that the model does predict the effect of particle size, fiber size, bed length, and degree of saturation consistent with experimental observations. However, the coalescence efficiency based upon aerosol filtration theory is not amenable to the fibrous bed over the widest range of flow velocities.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490305

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

年代:1971

数据来源: WILEY

摘要:

AbstractAn analysis of the energy transport to eddies in transit from the turbulent core to the wall region coupled with the elementary surface renewal and penetration model is presented for the turbulent tube flow of liquid metals. Previous formulations of the various forms of the surface renewal and penetration model have been based on the assumption that eddies arrive at the surface with initial temperature T1equal to the bulk stream temperature Tb. However, due to the significance of molecular transport during the flight of eddies from the turbulent core to the wall region, the employment of this assumption immediately restricts the model to the analysis of the mean heat flux for fluids other than liquid metals. In contrast, the present analysis gives rise to an expression for the mean Nusselt number for turbulent tube flow which is shown to be applicable to fluids with moderate values of the Prandtl number (Pr = 0.5 ‐ 5.0) as well as to the flow of liquid metals at high values of the Reynolds numbe

ISSN:0008-4034    

DOI:10.1002/cjce.5450490306

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

年代:1971

数据来源: WILEY

摘要:

AbstractEquations are developed for predicting local heat‐transfer coefficients over the forward‐facing half of a cylinder during transverse, mist flow. At low approach velocities predicted values are found to be in good agreement with corresponding measured values. With increase in approach velocity, agreement is found to fall off owing largely to the onset of a severe splashing or bouncing action. This effect is examined, together with effects of evaporation and convection at the free surface of the liquid layer formed on the cylin

ISSN:0008-4034    

DOI:10.1002/cjce.5450490307

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

年代:1971

数据来源: WILEY

摘要:

AbstractBased on the surface renewal and penetration concept, a number of fairly general mathematical models for transport systems without chemical reaction or heat generation and transport systems with zero and first order reactions have been developed. Solutions of the governing transport equations are presented for cases in which the number of capacitors of the multiple capacitance age distribution is finite or infinite. Some of their limiting solutions are reduced to those proposed by the previous investigators.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490308

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe results of an experimental study of the influence of vessel dimensions and fluid velocity on residence time distributions (RTD's) are presented. Length to diameter ratio (L/D) exerts the major influence on the RTD for the range of sizes and velocities studied. At L/D ≤ 2.6, the RTD resembles the response of a well stirred vessel with by‐passing to a pulse signal. Both Reynolds No. (NRe) and nozzle to vessel diameter ratio (d/D) effect the RTD. At L/D ≥ 5.2, the RTD resembles the response of stirred tanks in series to a pulse. NReand d/D do not effect the RTD and can be neglected for scale‐up. The second and third moments of the RTD's and parameters of a finite stage model fitted to the RTD relate qualitatively to L/D, d/D and NRe, but neither the moments or the particular finite stage model used are satisfactory for quantitative corre

ISSN:0008-4034    

DOI:10.1002/cjce.5450490309

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

年代:1971

数据来源: WILEY

摘要:

AbstractA maximum likelihood ratio was used as a statistical criterion for discriminating among twenty‐two kinetic models posited to describe the hydrogenation of mixed pentenes (cis‐ and trans‐2‐pentenes) with a Raney nickel catalyst. Selectivity ratio, the ratio of reaction rates of two different species, was used and found to be a suitable extension of conventional techniques for identifying rate controlling steps owing in this case to its reproducibility. Selectivity ratio models were of the Langmuir‐Hinshelwood form.Hydrogenation was performed isothermally at 20°C in benzene at five constant pressures corresponding to partial pressures of hydrogen of 22.5, 42.3, 62.3, 112.3 and 122.1 psia.Discrimination was attempted at each pressure, but found acceptable only at the three intermediate pressures. At each of these pressures, a model of similar functional form was found to represent the selectivity data; however, this model appears to be empirical.The likelihood ratio approach appears to be a powerful one for discriminating among a large number of models even with only a moderate number (˜ 20) of experimental o

ISSN:0008-4034    

DOI:10.1002/cjce.5450490310

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

年代:1971

数据来源: WILEY