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Showing papers on "Volumetric flow rate published in 1981"


Journal ArticleDOI
TL;DR: The possibility of using pulsed current in electrochemical machining at low electrolyte flow rate has been investigated in this article, where theoretical aspects of predicting electrolyte heating and limiting rate of mass transport are discussed in terms of simplified models.

143 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured local hold-up and liquid recirculation rate in an air-lift reactor with two types of gas spargers using a manometric technique.
Abstract: Measurements of local hold-up and liquid recirculation rate in an air-lift reactor were performed with two types of gas spargers using a manometric technique. A simple exponential function correlated properly the liquid velocity measured to the gas flow rate. The local hold-up varied appreciably along the column and showed a maximum in most of the cases. A simple linear relationship correlated the local gas velocity with the total flow rate of the mixture.

136 citations


Journal ArticleDOI
TL;DR: In this article, the effect of the choice of shape and dimensions of the air flow passages in plate-type, air-heating solar collectors is assessed, and their effect on the overall heat transfer coefficient between the air stream and the plate is discussed.
Abstract: The effect of the choice of shape and dimensions of the air flow passages in plate-type, air-heating solar collectors is assessed. Particular examination is made of their effect on the overall heat transfer coefficient between the air stream and the plate, which has an important effect on collector efficiency. It is emphasized in this study that in comparing various designs of flow passage, they should be compared for the same pressure drop suffered by the air in passing through the collector, and for the same mass flow rate m per unit of collector area. 11 refs.

114 citations


Journal ArticleDOI
01 Jan 1981
TL;DR: In this article, a further theoretical analysis was performed on the excess enthalpy flame system proposed by Takeno and Sato to burn mixtures of low heat content, and the analysis was extended to include effects of the finite length of the porous solid inserted for internal heat recirculation, so as to predict the flammability limit.
Abstract: A further theoretical study was performed on the excess enthalpy flame system proposed by Takeno and Sato to burn mixtures of low heat content. The previous analyses were extended to include effects of the finite length of the porous solid inserted for internal heat recirculation, so as to predict the flammability limit. In the analysis the temperature of the solid is an eigenvalue of the system, while mass flow rate remains a controllable parameter. Numerical calculations have revealed the existence of a critical mass flow rate above which combustion cannot be sustained. The critical flow rate is more than ten times the burning velocity for a thin porous disk of the order of the flame thickness. Below the critical flow rate, the system has two combustion states with the distinct solid temperatures. As the flow rate is decreased asymptotically to the burning velocity, the inserted disk comes to play the role of a downstream flame holder for the state with the higher solid temperature, whereas it plays the role of an upstream flame holder for the state with the lower solid temperature.

110 citations


Journal ArticleDOI
TL;DR: In this article, the intrinsic kinetic data from the process kinetic measurements in a trickle-bed reactor was used to evaluate the effect of axial dispersion on mass transfer coefficients, which were then used to calculate the intrinsic transfer coefficients.

100 citations


Journal ArticleDOI
H. Pascal1
TL;DR: In this paper, the threshold gradient effect in nonsteady flow through a porous media is investigated and its role on the pressure and flow rate distributions in a flow system is evaluated.
Abstract: In this paper the threshold gradient effect in the nonsteady flow through a porous media is investigated and its role on the pressure and flow rate distributions in a flow system is evaluated. The system considered in this investigation is a linear oil reservoir. Two situations of practical interest, i.e. reservoir depleted at a constant pressure and at a constant flow rate, are considered. The solutions in a closed form for this flow system are obtained. A comparison between the pressure distributions obtained analytically, numerically and by the integral method is also presented. In order to illustrate the effect that threshold gradient would have on the flow behavior, several numerical examples are given. The results derived from this investigation show that the flow behavior in the presence of a threshold gradient depends strongly on two dimensionless parameters. These parameters are directly related to the threshold gradient, the physical properties of the porous medium and the flow parameters at the outface flow.

92 citations


Journal ArticleDOI
TL;DR: In this article, critical heat flux and rate of droplet entrainment due to bubble bursting are made with boiling liquid films flowing downwards on the outside surface of a uniformly heated vertical tube.

86 citations


Patent
15 Oct 1981
TL;DR: In this article, a method of determining the mass flow of a fluid comprising measuring a plurality of parameters comprising the pressure P, the temperature T and the density ρ of the fluid was proposed.
Abstract: A method of determining the mass flow of a fluid comprising measuring a plurality of parameters comprising the pressure P, the temperature T and the density ρ of the fluid, determining the specific gravity G of the fluid from the said parameters, and using the measured density ρ together with a further parameter which varies with the volumetric flow to evaluate the mass flow of the fluid only if the so-determined value of G is within a given range of values.

80 citations


Patent
Evans John L1
28 Sep 1981
TL;DR: In this article, a method for controlling the flow of drilling fluid through a subaqueous wellbore is disclosed, which comprises the steps of continuously measuring the output flow rate (A) of the drilling fluid from the well-bore, the input flow rate of the fluid to the vessel, and at least a component of the pitch and roll (P/R) signal and the roughness of the sea.
Abstract: A method for controlling the flow of drilling fluid through a subaqueous wellbore is disclosed. The method comprises the steps of continuously measuring the output flow rate (A) of the drilling fluid from the wellbore, the input flow rate (B) of the drilling fluid to the wellbore, and at least a component of the pitch and roll (P/R) of the vessel, computating a floating alarm limit (C) dependent upon the pitch and roll (P/R) signal and the roughness of the sea, filtering the periodic fluctuation of the output flow rate (A) due to the motion of the vessel, and computating the delta flow signal (D) by subtracting the input flow rate (B) from the filtered output flow rate (A). The method further comprises the step of generating a signal whenever the absolute value of the delta flow rate (D) exceeds the floating alarm limit (C) to provide a visible warning that the flow of drilling fluid is out of control and to either close off the wellbore in case of a kick or to stop the flow of fluid and stop drilling in case of lost returns. Apparatus for controlling the flow of drilling fluid through a subaqueous wellbore is disclosed while drilling from a floating vessel. The wellbore is connected to the lower end of the drill string and the lower end of an annulus by a valve through which the drilling fluid flows. The upper end of the annulus is connected to a conduit from which the drilling flows to the suction side of a pump which circulates the drilling fluid therefrom into the upper end of the drill string, through the wellbore, and back up the annulus into the conduit. The apparation comprises an output flow meter connected to the exit of the conduit, an input flow meter connected between the pump and the upper end of the drill string, means mounted on the vessel for sensing the pitch and roll of the vessel, and computer means for receiving the output flow rate (A) signal from the output flow meter, the input flow rate (B) from the input flow meter, and the pitch and roll (P/R) signal from the pitch and roll sensing means. The computer means calculates an alarm limit (C) based on the pitch and roll (P/R) signal and the roughness of the sea continuously filters the periodic fluctuation of the output flow rate (A) due to the motion of the vessel, computes the delta flow signal (D) by subtracting the input flow rate (B) from the filtered output flow rate (A), and generates a signal whenever the delta flow rate (D) exceeds the floating alarm limit (C) to provide a warning of a possible blowout or lost circulation condition and to either close off the wellbore in case of a kick or to stop the flow of fluid and stop drilling in case of lost returns.

78 citations


Patent
29 Jun 1981
TL;DR: In this paper, a method and apparatus for measuring and controlling volumetric flow rate of gases, and especially for delivering gases at a selected and measured VOLUMEUME 7, 2019 flow rate is described.
Abstract: Disclosed is a method and apparatus for measuring and controlling volumetric flow rate of gases, and especially for delivering gases at a selected and measured volumetric flow rate. The apparatus includes a measurement chamber (14) of fixed volume in a flow line (11), a controllable inlet valve (15) upstream from the chamber, and flow regulator means (12, 13) for establishing constant flow output downstream from the chamber. Also provided are measuring and control equipment including a pressure sensor (16) in the chamber, means (17) for controlling operation of the inlet valve, timing means, and means for calculating volumetric flow rate. The method involves closing the inlet valve at a chosen time for a selected interval, to interrupt flow into the measurement chamber, while maintaining constancy of flow out of the chamber. During at least part of the interval in which the inlet valve is closed, the pressure decrease is measured, and the rate of pressure decrease is calculated by dividing the measured pressure drop by the time measured by the timing means. The thus calculated rate of fall of pressure is directly related to the volumetric flow rate, which is thus determined. If the nature of the gas and the flow conditions are such that the supercompressibility of the gas should be taken into account, rate of pressure fall is determined at two time intervals. If the two rates are the same, no correction is needed. If they differ, a supercompressibility correction factor is applied to the calculation of rate of pressure fall.

60 citations


Patent
20 Jul 1981
TL;DR: In this paper, a method and an apparatus for controlling the viscosity of a mixture by controlling the volumetric flow of a fluid with respect to the volume of another fluid is disclosed.
Abstract: A method and an apparatus for controlling the viscosity of a mixture by controlling the volumetric flow of a fluid with respect to the volumetric flow of another fluid is disclosed. The apparatus includes volumetric flow detectors for detecting the flow of the two fluids. The apparatus also includes an electronic controller device which responds to electrical signals generated by the volumetric flow detectors in proportion to the respective detected volumetric flows. The output of the controller device operates a flow drive element, such as a pump, so that the volumetric flow of one of the fluids is controlled. The volumetric flow of the controlled fluid and the volumetric flow of the other fluid are mixed by a suitable mixer device to obtain the mixture having the desired viscosity.

Journal ArticleDOI
Davor Pavuna1
TL;DR: In this paper, the results of extensive studies on the production of metallic glass ribbons by a single jet chill-block melt-spinning technique in laboratory conditions are summarized with emphasis on the data of practical importance.
Abstract: The results of extensive studies on the production of metallic glass ribbons by a single jet chill-block melt-spinning technique in laboratory conditions are summarized with emphasis on the data of practical importance. A device that stabilizes quenching conditions by surrounding the melt puddle with an atmosphere of He gas is described. The conditions for high stability are defined. The dependence of ribbon width and thickness on the volumetric flow rate, injection angle and substrate velocity are experimentally determined in such stabilized conditions. The cross-sectional geometric uniformity of the ribbons, analysed by Talysurf, is shown to be comparable with those produced by commercial laboratories, and/or within specially constructed chambers.

Journal ArticleDOI
TL;DR: In this paper, an economic comparison is made between electrode configurations for flow redox battery applications: (i) the flow-through configuration (current parallel to the fluid flow) and (ii) flow-by configuration(current perpendicular to fluid flow). Steady state computer models are developed for each electrode system.

Patent
21 Dec 1981
TL;DR: In this article, an improved mass flow meter is disclosed for measuring the flow rate of a fluid through a thin walled sensor tube that has the feature of high sensitivity to the temperature of the fluid within the sensor tube.
Abstract: An improved mass flow meter is disclosed for measuring the flow rate of a fluid through a thin walled sensor tube that has the feature of high sensitivity to the temperature of the fluid within the sensor tube. The sensor tube is wound with closely coupled resistance elements of insulated wire. Measurement is accomplished with a conventional bridge connection to the sensor resistance elements. The bridge is designed to remain in balance over a wide range of ambient temperature at a zero flow rate. Fluid flow through the sensor tube upsets the uniform temperature gradient with heat loss being greater upstream so that the balance of the sensor resistance elements installed or coupled to the sensor tube (which elements are heated by a power supply) is progressively upset with increasing flow. External heat loss is reduced (thereby providing greater temperature sensing ability) by surrounding the sensor tube with a polyester fiber insulating material covered with a metallic heat shield and by connecting the flow meter into the fluid stream through thermal insulating couplings.

Patent
09 Sep 1981
TL;DR: In this article, a single-stroke syringe-type high pressure pump is used to stabilize flow rate in a single stroke, syringe type pump to a constant value after turn-on, a control system increases the pump speed until equilibrium conditions are reached and then pumps at the preset rate.
Abstract: To stabilize flow rate in a single-stroke, syringe-type high pressure pump to a constant value after turn-on, a control system increases the pump speed until equilibrium conditions are reached and then pumps at the preset rate. In one embodiment, the control system senses the maximum rate of change of pressure, detects a pressure when the rate of change is two-thirds of the maximum, increases the pump rate until the pressure is three times that at the value of the detected pressure and begins pumping at the preset constant flow rate. In other embodiments: (1) a pumping system is operated at a flow rate ten times the preset flow rate and, when the time derivative of the pressure has dropped to nine tenths of its maximum, the pump motor speed is reduced to the preset flow rate; (2) the outflow of the column is measured under no load conditions at the desired flow rate and when a column is connected, the pumping speed is increased until the same outflow results before reducing the pumping rate; and (3) the system is operated in a constant pressure mode to a point at which the pressure is estimated to provide the desired flow rate, the flow rate measured, and if the flow rate is not the preset one, a new pressure measurement is set and the procedure repeated. In a constant pressure system, the speed of a recording chart is adjusted to the pumping speed to provide a chromatogram with abscissae of flow rate units.

Journal ArticleDOI
TL;DR: In this article, a new experimental technique has been developed and used to study the mass transfer characteristics of two-phase bubble columns, and liquid side volumetric mass transfer coefficients have been calculated for both models.
Abstract: One of the most persistent obstacles in the study of oxygen mass transfer in bubble columns is the technical difficulty of using large liquid and gas flow rates economically. This experimental limitation is reflected in the present, very incomplete, understanding of the mass transfer characteristics of these two-phase systems. In this work, a new experimental technique has been developed and used. The use of computer-calculated concentration contour diagrams permitted a detailed study of the mass transfer characteristics of the zone near the distributor. No similar study has been reported in the literature until now. The ability of the axial dispersion and two-zone models to describe the experimental data is analyzed. Finally, liquid side volumetric mass transfer coefficients have been calculated for both models. The results indicate that KLa increases, often linearly, with the superficial gas velocity. Furthermore, for the liquid-phase range [0, 10] cm/s, KLa had a minimum at Vl ∼ 7.5 cm/s. For larger liquid superficial velocities, an increase in KLa was found. These observations were valid for the axial dispersion (ADM), plug flow (PFM) and two-zone (T-ZM) models.

Journal ArticleDOI
TL;DR: In this article, the authors present a method for calculating the flow rate of circulating oil in self-cooled transformers, obtained in measurements with models and also present flow rate characteristics of such transformers.
Abstract: This paper presents a method for calculating the flow rate of circulating oil in self-cooled transformers. The flow rate characteristics of such transformers, obtained in measurements with models are also presented

Journal ArticleDOI
TL;DR: In this paper, a method is proposed for experimentally determining parameters characterizing the microstructure of a liquid, based on measurement of the specific volumetric flow rates of the liquid as it is pumped through two capillary tubes of different cross-sections.
Abstract: A method is proposed for experimentally determining parameters characterizing the microstructure of a liquid. The method is based on measurement of the specific volumetric flow rates of the liquid as it is pumped through two capillary tubes of different cross section.

Journal ArticleDOI
TL;DR: In this paper, the authors measured critical heat flux and liquid film flow rate at exit end of the test tube with Freon 113 upward flow in a uniformly heated tube, and proposed a correlation for the critical condition with high heat fluxes, suggesting that liquid film separation from the heated surface by vapor generation takes an important part of the critical phenomenon.

Patent
10 Jun 1981
TL;DR: In this article, the authors present a method for measuring and determining the total energy flow, that is, BTUs per minute, of combustible gas flowing through a line such as a pipeline.
Abstract: Disclosed are methods and apparatus for measuring and determining the total energy flow, that is, BTUs per minute, of combustible gas flowing through a line such as a pipeline. One method includes taking a continuous sample of the gas flowing through the line which sample is a constant proportion of the gas flowing through the line, and burning the sample in equipment which supplies air to the sample in an amount which maximizes its burning temperature. The flow rate of air which produces the maximum burning temperature of the sample is a flow rate which is directly proportional to the rate of energy flow in the main pipeline. Alternately, the flow rate of air which produces a stoichiometric mixture is directly proportional to the rate of energy flow in the main pipeline. Still further, if an excess of air is flowed to the flame, the amount of excess unconsumed oxygen is also a function of the rate of energy flow in the main pipeline. One or another of these parameters is measured. Also disclosed is equipment capable of effectively performing the several steps of the method.

Patent
27 Aug 1981
TL;DR: In this paper, an end point detection method for plasma etching of integrated circuit wafers is presented, which is conducted in a chamber subjected to the vacuum of a pump drawing at a constant volumetric gas flow rate.
Abstract: Apparatus and methods for end point detection during the plasma etching of integrated circuit wafers. Etching is conducted in a chamber subjected to the vacuum of a pump drawing at a constant volumetric gas flow rate. The etchant gases entering the chamber are regulated by a controller responsive to a feedback loop sensing pressures within the chamber. Changes in the chamber's chemical composition, which occur in time proximity to the end point of etching, affect the pressure and are detected as variations in the gas flow rates. Empirical results confirm the distinctiveness and repeatability which characterize the flow variations at the end point of etching.

Journal ArticleDOI
TL;DR: In this article, the state of the art and ongoing research concerning the flow of wet steam in large steam turbines is reviewed, particularly from the viewpoint of the behavior of the liquid film deposited upon the stationary blading.
Abstract: The state of art and ongoing research concerning the flow of wet steam in large steam turbines is reviewed, particularly from the viewpoint of the behavior of the liquid film deposited upon the stationary blading. New experimental results concerning the non-steady behavior of the film and the resultant wavelet formation patterns under the action of high-velocity low-pressure steam flow are presented. These results are then correlated as a flow regime “map” showing various flow regions in terms of steam velocity (or relative steam-film velocity since film velocity is relatively very small) vs. film flow rate per unit transverse distance.

Patent
02 Oct 1981
TL;DR: In this article, an elongated body member with a funnel configuration attached to it is used for collecting and mixing the multiple fluid phases in a well containing a multi-phase fluid flow regime, where an aperture is provided in the body member, proximate to the apex of the funnel configuration, to allow the dicharge of the substantially homogeneous mixture of the fluid phases from the funnel through a passage in a body member.
Abstract: In a well containing a multi-phase fluid flow regime is disposed an elongated body member with a funnel configuration attached thereto for the purpose of collecting and mixing the multiple fluid phases. An aperture is provided in the body member, proximate to the apex of the funnel configuration, to allow dicharge of the substantially homogeneous mixture of the fluid phases from the funnel through a passage in the body member. A rotor is acted upon by the flow of this mixture and generates a signal representative of the mixture flow rate. A portion of the mixture then enters a chamber in the elongated body member wherein a measurement is made of the degree of penetration of the mixture achieved by gamma radiation, thereby yielding a measurement representative of the density of the mixture. The flow rates and volumetric fractions of each of the individual phases may then be determined in accordance with the mixture density and total flow rate.

Patent
15 Sep 1981
TL;DR: In this paper, a system for measuring the flow rate of electrolytic fluids includes a flow cell which has a cylindrical flow channel receptive of the fluid flow to be measured and a pair of spaced apart electrodes configured to conform to the surface of the flow channel and to be flushed therewith.
Abstract: A system for measuring the flow rate of electrolytic fluids includes a flow cell which has a cylindrical flow channel receptive of the fluid flow to be measured and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and to be flushed therewith. The electrodes are electrically conductive and inert to the fluid of the flow and a channel is configured to effect contact of the electrodes with the fluid flow for a desired range of flow measurement. A monopolar pulse train is applied across the electrodes to effect a cell impedance across the electrodes which is inversely proportional to the rate of flow. A control signal is produced in response to the potential across the electrodes for a given unit of time and this control signal is applied to a generator for producing the monopolar pulse train in order to vary the pulse train current in the given unit of time to effect an increase in the current in response to an increase in flow rate whereby the cell impedance is stabilized for every flow rate and the electrode potential is representative of the flow rate.

Patent
30 Sep 1981
TL;DR: In this article, a method of operating a plasma generating apparatus including at least one multi-bushed torch unit is described, where the ratio of inside gas flow rate to outside gas flow ratio in the channels of the torch unit are experimentally determined so as to assure the alignment of the electric arc in the unit, and the plasma generator is operated with the gases flowing at so-determined flow rates.
Abstract: Disclosed is a method of operating a plasma generating apparatus including at least one multi-bushed torch unit. The ratio of inside gas flow rate-to-outside gas flow rate in the channels of the torch unit are experimentally determined so as to assure the alignment of the electric arc in the torch unit, and the plasma generating apparatus is operated with the gases flowing at the so-determined flow rates.

Patent
11 May 1981
TL;DR: In this article, the authors simplify the constitution of a pressure fluid circuit and facilitate its remote control by providing a plurality of fluid circuits and a flow dividing circuit which preferentially supplies one of the fluid circuits with a flow fluid as well as has a function of controlling the flow rate.
Abstract: PURPOSE:To simplify the constitution of a pressure fluid circuit and facilitate its remote control by providing a plurality of fluid circuits and a flow dividing circuit which preferentially supplies one of said fluid circuits with a pressure fluid as well as has a function of controlling the flow rate. CONSTITUTION:A pressure fluid circuit comprises a main circuit 2 to which a pressure fluid source 1 is connected, the first and second fluid circuits 3 and 4 provided with supply circuits 17a and 17b and directional control valves 10a and 10b to cotrol the flow directions of the pressure fluids from said supply circuits, and a flow dividing circuit 5, which is provided with a controlled input unit 35 and supplies the pressure fluid from the main circuit 2 to the first fluid circuit 3 with a flow rate according to the input applied to the controlled input unit 35 and also supplies the surplus of said pressure fluid to the second fluid circuit 4 through a flow dividing valve 36 and a flow regulating valve 37 which is provided between the flow dividing valve 36 and the supply circuit 17a and which throttles the flow rate according to the difference between the pressure of the fluid discharged from the flow dividing valve 36 and the fluid pressure in the supply circuit 17a.

Journal ArticleDOI
TL;DR: The effect of various performance parameters on flux during the hollow fiber ultrafiltration of defatted soy flour extracts was studied in this paper, where a modified power law version of the Poiseuille equation, J= A (▵PT)n, best fit the data, where J is the flux, ▵PT is the transmembrane pressure and A and n are constants characteristic of a particular membrane-feed combination.
Abstract: The effect of various performance parameters on flux during the hollow fiber ultrafiltration of defatted soy flour extracts was studied. Flux was significantly affected by pressure up to the limits of the unit. Higher temperatures also increased flux. However, flow rate had practically no effect. Also, no hysteresis effects were observed upon lowering the pressure from the highest to lowest values. The data indicated that concentration polarization or mass transfer was not rate-controlling and flux behavior could be modelled by momentum transfer considerations. A modified power law version of the Poiseuille equation, J= A (▵PT)n, best fit the data, where J is the flux, ▵PT is the transmembrane pressure and A and n are constants characteristic of a particular membrane-feed combination. A and n decreased with increasing solids in the feed, and A increased while n decreased with increasing temperature.

Patent
21 Dec 1981
TL;DR: In this article, a partial oxidation gas generator for the production of synthesis gas, reducing gas, or fuel gas is effected by two improved control schemes which are automatically operated separately or in sequence.
Abstract: Trim control of a partial oxidation gas generator for the production of synthesis gas, reducing gas, or fuel gas is effected by two improved control schemes which are automatically operated separately or in sequence The control systems include sensors sensing the flow rate of the feedstreams and analyzers which provide signals corresponding to the wt % carbon in the effluent gas quench cooling and scrubbing water for use in controlling the particulate carbon in the effluent gas stream, and/or signals corresponding to the mole fractions of CO 2 , CH 4 , CO and H 2 (dry basis) in the cooled and cleaned effluent gas stream for use in controlling the temperature in the reaction zone The signals from the sensors and analyzers are provided to the system control unit which computes values that represent the relative difference between the actual and desired carbon-make and/or the actual temperature in the reaction zone, and the relative difference between the actual and desired temperature in the reaction zone The actual temperature is determined as a function of the methane equilibrium constant These values are automatically compared with set point values and when adjustments are necessary, signals from the system control unit are provided to a flow rate regulating means which adjusts the flow rate of the free-oxygen containing gas by a small determined amount for control of the particulate carbon and/or to a flow rate regulating means which adjusts the flow rate of the temperature moderator by a small determined amount for control of the temperature in the reaction zone

Journal ArticleDOI
TL;DR: In this paper, a gas flow-rate and pressure control unit suitable for use with cathodicsputtering cells is described, which uses semi-automatic control to allow rapid sample exchange and precise reproduction of gas flow rate and pressure.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the rates of mass transfer under the influence of a temperature gradient between the menisci of ice in a thin quartz capillary and determined the mass transfer rate by the diffusion of vapor and by the flow of a nonfrozen polymolecular adsorption film over the capillary surface.