ISSN:0001-1541    

DOI:10.1002/aic.690140302

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690140304

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractPool nucleate boiling heat transfer curves for pure nitrogen, oxygen, argon, methane, and carbon tetrafluoride have been measured on a horizontal, flat, circular, platinum plated disk for saturation pressures ranging from 1 atm. or less to the immediate vicinity of the critical pressure for each liquid. The results have been compared with various suggested nucleate boiling correlations, and the correlations of McNelly, of Kutateladze, and of Borishanskiy‐Minchenko are found to be roughly equally successful and all distinctly superior to those of Rohsenow, of Gilmour, and of Forster and his collaborators for these liquids. For oxygen, argon, methane, and carbon tetrafluoride, boiling hysteresis of a type not previously reported was observed at intermediate and high saturation pressures on this surfac

ISSN:0001-1541    

DOI:10.1002/aic.690140307

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractPeak nucleate boiling fluxes (P.N.B.F.'s) for nitrogen, oxygen, argon, methane, and carbon tetrafluoride on a flat, horizontal platinum plated copper disk were measured up toPr>0.95. The P.N.B.F. correlation in the form proposed by Chang and Snyder and various other investigators is superior, for these liquids, to those of Addoms, Noyes, Borishanskiy, and Moissis and Berenson. The P.N.B.F. on a given surface is found to be reproducible to within a few percent, but exposure of that surface to other test liquids or even to the laboratory atmosphere can produce changes of ± 15%

ISSN:0001-1541    

DOI:10.1002/aic.690140308

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractNucleate boiling curves and peak nucleate boiling fluxes (P.N.B.F.'s) have been measured for oxygen‐nitrogen mixtures of 3.25, 8.35, and 68.5 mole % oxygen and for carbon dioxide free air on a flat horizontal platinum surface from 1 atm. toPr˜ 0.95.The nucleate boiling correlations of Kutateladze and of Borishanskiy‐Minchenko, which were successful for the pure components, fail for the mixtures at elevated pressures. Of the correlations tested, that of McNelly is most nearly successful for both pure components and for their mixtures at all pressures.The Chang‐Snyder form of the Kutateladze correlation for the P.N.B.F. is successful for mixtures up to Pr= 0.75, beyond which it overpredicts the P.N.B.F. No anomalies in P.N.B.F. at 1 atm. similar to those reported for binary aqueous systems were ob

ISSN:0001-1541    

DOI:10.1002/aic.690140309

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractThe movement of solids associated with the rise of a single gas bubble in an incipiently fluidized bed has been determined. The bulk volume, measured at the porosity of incipient fluidization, of tracer solid which is transported across the original interface between undyed glass spheres in the upper region and dyed glass spheres (tracer solid) in the lower region, is approximately 30% of the bubble volume. The measurements relate to bubble volumes from 14 to 200 ml. in a glass column, 4 in. diam. Solids used were glass spheres of diameter 380 μ. The profile created when a bubble rises through a layer of fluidized tracer solids into the fluidized solids above the tracer layer has been approximately determined. The distance by which the solids were displaced upward, due to the passage of the bubble, was found to be greater than would have been the case if the behavior were that of a sphere in an inviscid liquid

ISSN:0001-1541    

DOI:10.1002/aic.690140310

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractIn gas‐metal permeation, diffusion is normally considered to be the rate‐controlling step. In addition, the diffusivity is usually taken to be independent of concentration. Under these conditions, the time lag (a characteristic of the system which depends on the time required to achieve steady state flow) is found to be (and theoretically should be) independent of the gas pressure applied to the inlet surface of the metal membrane. Furthermore, the time lag can then be directly related to the diffusivity of the system.In this paper, data on the hydrogen type 321 stainless steel system are presented which show a pronounced effect of pressure on measured values of the time lag. Taken alone, these data can be explained either by a concentration‐dependent diffusivity or by resistance to flow at the metal surface. From steady state data it is shown that surface resistance is the better explanation. A model of the permeation process is presented which is consistent with the time lag data, and an estimate is made of the diffusivity of hydrogen in type 321 stainless steel.The variables studied were hydrogen pressure at the entrance surface of the membrane (0.1 to 30.0 atm.), temperature (300° to 800°C.), and membrane wall thickness (0.0252 to 0.24

ISSN:0001-1541    

DOI:10.1002/aic.690140311

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractTemperature profiles of dispersed kerosene and water were measured in a spray column heat exchanger, 15 cm. in diameter and 160 cm. long. Dispersed packing of drops and narrow temperature ranges were used. The flow rates used were 0 to 50 liters/min. of water and 5 to 40 liters/min. of kerosene. The physical picture that emerges from the temperature profiles is that heat is transferred from fully mixed drops to fully mixed wakes while the wakes are formed, by shedding and renewal of elements of wakes in most of the column and by complete mixing of all streams at the water inlet at the top of the column. Mathematical equations were developed from the physical model. The volume of the wakes and the rate of shedding of wake elements were estimated from the temperature profiles and were used to calculate the temperature profiles for this and for other studies. The agreement of the calculated profiles with the experimental data is very good.

ISSN:0001-1541    

DOI:10.1002/aic.690140312

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractAn analysis is presented which extends the analogy between energy and momentum transport for turbulent pipe flow of purely viscous fluids to include drag reducing, non‐Newtonian fluids. The correlation by Meyer is used to predict friction factor and sublayer thickness for the drag reducing fluids. The use of the friction factor correlation with the heat transfer analogy makes it possible to predict heat transfer rates from simple measurements of pressure drop and flow rate for the drag reducing fluids. Some recent experimental data for two effective drag reducing fluids and for water are compared with the predicted heat transfer rates, and the mean deviation in Nusselt number is found to be +8.5% for all of the data. The heat transfer analysis predicts a reduction in Nusselt number accompanying a reduction in friction factor for a given Reynolds number and for Prandtl numbers greater than

ISSN:0001-1541    

DOI:10.1002/aic.690140313

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractThe profile of a growing droplet was determined with a pressure balance which was similar to that derived by Laplace for the static droplet. An additional term was added to the balance to account for the pressure on the interface due to the motion of the fluid within the droplet. The entire pressure balance was then combined with differential equations describing the geometry of the droplet. Computed profiles compared favorably with those obtained experimentally.An additional result was the definition of a parameter,f, indicating the importance of internal fluid motion on the shape of the profile. A method of estimating this parameter without solving the equations was developed.

ISSN:0001-1541    

DOI:10.1002/aic.690140314

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY