摘要:

AbstractResults of visual observations and measurements of holdup and pressure drop are reported over a range of air‐water ratios for the upwards vertical flow of air‐water mixtures in four tubes with diameters ranging from 0.630 in. to 2.50 in. Tests were conducted under conditions of constant air density corresponding with an average pressure of 36 psia and at 10 constant superficial water velocities ranging from 0.0695 to 7.35 ft./sec.The data are analyzed by the method previously suggested by Govier, Radford and Dunn involving the separation of the unit pressure drop curves into four regimes to aid in flow pattern description and the separation of the unit pressure drop itself into two components to facilitate correlation.Tubing diameter is found to have little or no effect on the border between Regimes I and II or on the transition from the bubble to the slug flow pattern. The borders between Regimes II and III and between Regimes III and IV are markedly affected by tubing diameter as by consequence are the transitions from slug to froth and from froth to ripple flow.Tubing diameter is found to have an important effect on the superficial friction factor and the holdup. The pressure drop data for each of the diameters have been successfully brought together in a single friction factor‐Reynolds number correlation. The holdup data are separately correlated for pressure drop Regimes I and II and for Regime III and Regi

ISSN:0008-4034    

DOI:10.1002/cjce.5450360501

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

年代:1958

数据来源: WILEY

摘要:

AbstractThe volume of heavy water required for a power reactor plant using this moderator has an important influence on investment. Likewise, the cost of leakage justifies extraordinary containment measures. A heat exchanger design is described which satisfies these requirements, as well as those imposed by the radiation field in which the equipment must operate.

ISSN:0008-4034    

DOI:10.1002/cjce.5450360502

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

年代:1958

数据来源: WILEY

摘要:

AbstractBy employing recently secured data for the axial dispersion of mass flowing through fixed beds, it is shown that for first order isothermal processes conducted in fixed beds of practical aspect ratios (L/Dp), the effect of mixing upon kinetics is insignificant. It follows that in shallow bed systems usually employed in kinetic research efforts, the influence of axial mixing cannot be ignored, particularly in the case of a liquid reactant. The dispersion data and the analyses support the contention of Ergun(14)and the recent treatment of the problem by Epstein(16).

ISSN:0008-4034    

DOI:10.1002/cjce.5450360503

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

年代:1958

数据来源: WILEY

摘要:

AbstractBased on the model of a fixed bed as a series of perfect mixers, a factor is derived for correcting the logarithmic mean driving potentials in the conventional plug‐flow equations for fluid‐particle heat and mass transfer in packed beds. This factor, which accounts for axial mixing and is a measure of the transfer efficiency of the bed relative to the idealized case where axial mixing is absent, increases towards unity with bed height but decreases with ratio of terminal driving potenti

ISSN:0008-4034    

DOI:10.1002/cjce.5450360504

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

年代:1958

数据来源: WILEY

摘要:

AbstractIn a power reactor the fuel will be operating under very severe conditions. Consequently before a fuel element can be designed it must be tested under conditions which are similar to those in the reactor, and the effect of a large number of variables on the behavior of the fuel must be investigated.This paper discusses the fuel development program at Chalk River with special reference to the testing of uranium oxide reactor fuels in loops inserted in the NRX reactor. In these loops water may be recirculated over the test elements at temperatures up to 550°F. and pressures up to 2000 psi. The characteristics of a loop are described and the results of various tests are briefly discussed.The testing of sheathing materials such as Zircaloy‐2 and aluminum‐nickel alloys is also descr

ISSN:0008-4034    

DOI:10.1002/cjce.5450360505

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

年代:1958

数据来源: WILEY

摘要:

AbstractThis report indicates the problems associated with the maintenance of the purity of the D2O in a pressurized heavy water power reactor and how these problems are handled.In a pressurized water power reactor, impurities will be introduced into the coolant and moderator from the corrosion of the steel system. These impurities are mainly particulate and colloidal in nature. They must be kept to a minimum since when circulated through the reactor they become activated by the neutron flux and when deposited throughout the system they make accessibility for maintenance difficult. Impurities may also be introduced into the water from fuel element ruptures. These also create maintenance problems since they are intensely radioactive.Heavy water systems require a constant guard against the introduction of light water which would degrade the D2O and make the operation of the reactor inefficient or perhaps impossible. The isotopic content of the heavy water must be checked constantly. Upgrading may be required periodically or continuously.The general purity of the water in the reactor is maintained by passing a fraction of the main circulating volume through a by‐pass containing a filter and a mixed bed ion exchange resin column. This column serves to remove ionic impurities as well as acting as an efficient filter itself. It is also used to maintain the pH of the water at the desired level whether neutral or alkaline. In the case of heavy water systems the resin must be deuterized before use to prevent degrading the D2

ISSN:0008-4034    

DOI:10.1002/cjce.5450360506

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

年代:1958

数据来源: WILEY

摘要:

AbstractRecently, considerable effort has been made to investigate mechanisms of heat and mass transfer to drops or bubbles passing through a continuous liquid medium. Many of these studies have been hampered by the unavailability of accurate methods for determining end effects.This paper outlines methods of plotting efficiency measurements for the overall transfer process so that both the magnitude of the end effects and the mechanism of the steady fall or rise period may be investigated. The examples are drawn from mass transfer with resistance inside the dispersed phase and from heat transfer with resistance in both phases. For resistance in one phase the methods are straight line extrapolations.Various mechanisms of transfer inside drops have been studied to test the methods of determining end effects.

ISSN:0008-4034    

DOI:10.1002/cjce.5450360507

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

年代:1958

数据来源: WILEY

摘要:

AbstractRE: Viscous Flow in Multiparticle SystemsThis abstract reviews a series of theoretical studies which has resulted in achieving a better understanding of such phenomena as resistance to flow of fluids through beds, sedimentation of small particles and viscosity of suspensions. There are many systems both in nature and technology involving these types of motion. Examples of commercial applications include the separation of particles by centrifuging and sedimentation, filtration, flow of gases through vessels containing packed solids (kilns, gas producers and blast furnaces), and motion of particles and gases in catalyst contracting vessels.

ISSN:0008-4034    

DOI:10.1002/cjce.5450360508

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

年代:1958

数据来源: WILEY