Showing papers on "Volumetric flow rate published in 1975"

A Theoretical Model for the Cavity Filling Process in Injection Molding

Abstract: The flow analysis network (FAN) method previously developed for die design is adapted to the problem of the cavity filling process in injection molding. The method is applicable to relatively narrow gap cavities of any shape. It permits the computation of the advancing front of melt at any time, as well as prediction of weld‐line location. The method was extended to nonisothermal flow in which solidification and “skin” formation during filling time was approximately accounted for. The nonisothermal analysis allows prediction of the possibility of a “short shot” situation. The analysis is applicable to any prescribed pressure or flow rate at the gate. Both can be arbitrary functions of time.

Apparatus for measuring the flow rate and/or viscous characteristics of fluids

Abstract: An apparatus for measuring the flow rate and/or viscous characteristics of a fluid comprising a casing having a fluid passage, a fluid inlet cavity and a fluid outlet cavity, fluid pressure detecting means preferably at spaced positions along the passage, and fluid pressure indicating means for indicating the or each characteristic to be measured in terms of the fluid pressure differential between the detecting means positions. The fluid inlet cavity provides a substantially unobstructed flow path to the fluid passage and the fluid outlet cavity provides a substantially unobstructed flow path therefrom. The fluid passage cross-sectional area decreases in the fluid flow direction in order to maintain laminar flow of the fluid therealong and wall boundary induced viscous shear therealong, over an extended range of Reynolds number within the fluid passage and formulae are given, using substantially pure water as a standard fluid, from which the limits of fluid passage geometry can be defined. In one embodiment the fluid passage is annular in shape and the fluid flow radially inward. The fluid passage may be divided into a plurality of substantially identical fluid passages to increase the flow rate capacity of the apparatus.

Diffusion controlled combustion of polymers

Abstract: A theoretical and experimental study of polymer combustion in an opposed flow diffusion flame (OFDF) is presented. An algebraic formula is derived, expressing the burning rate as a function of the fluid mechanic and thermodynamic variables. A polymer sample feed system has been developed which continuously positions the burning polymer surface within ±0.01 mm of a given set point, allowing accurate regression rate and detailed solid and gas phase flame structure measurements. Regression rate measurements of twelve commercial polymers as a function of oxygen concentration and oxidizer flowrate are reported. From these measurements and the theory, values of the Spalding transfer number, B , are derived and can serve as a useful flammability index for these materials. The OFDF technique also provides a quantitative method for evaluating the effectiveness of flame retardants. Solid and gas phase temperature profiles for charring and non-charring polymers under various oxygen concentrations and oxidizer flow conditions indicate markedly different chemical reaction mechanisms for charring and non-charring polymers.

Laminar flow of non-newtonian fluids in an eccentric annulus

Abstract: Esso Production Research Co. developed a technique for predicting the volumetric flow rate and velocity distribution for laminar flow of power-law and Bingham-plastic fluids in an eccentric annulus. This flow situation occurs during drilling of cementing of oil or gas wells. The volumetric flow rate is presented as a series of dimensionless plots of fluid properties, pipe diameters, eccentricity, and pressure drop, which are obtained by numerically integrating the velocity profile from a finite difference solution of the equations of continuity and motion after transformation into bipolar coordinates. The numerical procedure was verified by comparing the calculations with previously published results for the special cases of Newtonian flow in an eccentric annulus and non-Newtonian flow in a concentric annulus and with limited experimental data for Bingham-plastic flow in an eccentric annulus. The results indicate that the technique is accurate in predicting the volumetric flow rate and velocity distribution within the range of variables specified and on the degree of conformity of the fluid to the rheological model used.

Drip irrigation valve with helical flow path

Abstract: A drip irrigation valve comprising an outer member having a passageway and an inner member mounted in the passageway for axial movement. An axially and circumferentially extending rib is provided on a first of the members and cooperates with a confronting surface of a second of the members to provide a helical flow path. Dams are provided in the flow path to increase the resistance to fluid flow. To increase the flow rate, the members are moved axially to take one or more of the restrictions out of the flow passage. To make the valve pressure compensating, one of the member is resilient and can be resiliently deformed by the fluid at inlet pressure to increase the resistance to flow provided by the restrictions.

Magnetic transit-time flowmeter

Abstract: The flow rate of a conducting fluid in a stream is determined by disposing two permanent-magnet flowmeters in the stream, one downstream of the other. Flow of the conducting fluid causes the generation of both d-c and a-c electrical signals, the a-c comprising flow noise. Measurement of the time delay between similarities in the a-c signals by cross-correlation methods provides a measure of the rate of flow of the fluid.

Induction mixing nozzle

Abstract: An apparatus for mixing two fluids of the same phase. The apparatus includes a mixing nozzle, an adjustable flow rate injector for introducing an annular flow of primary fluid into the mixing nozzle at a selected primary fluid flow rate, and a nozzle port adjacent to the injector for introducing an induced annular flow of secondary fluid into the mixing nozzle, wherein the secondary fluid is of the same phase as the primary fluid. In this arrangement, the ratio of the secondary fluid flow rate to the primary fluid flow rate varies inversely with the primary fluid flow rate.

Flow Kinetics of β-Galactosidase Chemically Attached to Nylon Tubing

Abstract: β-Galactosidase (EC 3.2.1.23) has been attached covalently to the inner surface of nylon tubing. An experimental study has been made of the flow kinetics for the hydrolysis of o-nitrophenylgalactose, the substrate concentration and flow rate being varied. The results were analyzed in the light of the theoretical treatment of Kobayashi and Laidler, three different methods of analysis being employed. It is concluded that at the lower substrate concentrations and flow rates employed, the reactions are largely diffusion controlled; with increase in flow rate and substrate concentration the width of the Nernst diffusion layer decreases, and there is found to be less diffusion control. The values of Km(app) vary with flow rate VF, being linear in VF−1/3, and the value extrapolated to very high flow rate agrees well with the Km value for β-galactosidase in free solution. The theory and results are shown to provide guidelines for the design of open tubular heterogeneous enzyme reactors for industrial, biomedical,...

Maximum discharge rate of liquid-vapor mixtures from vessels

Abstract: A discrepancy exists in theoretical predictions of the two-phase equilibrium discharge rate from pipes attached to vessels. Theory which predicts critical flow data in terms of pipe exit pressure and quality severely overpredicts flow rates in terms of vessel fluid properties. This study shows that the discrepancy is explained by the flow pattern. Due to decompression and flashing as fluid accelerates into the pipe entrance, the maximum discharge rate from a vessel is limited by choking of a homogeneous bubbly mixture. The mixture tends toward a slip flow pattern as it travels through the pipe, finally reaching a different choked condition at the pipe exit.

Measurement and control of fluid flow

Abstract: An improved method and apparatus for measuring fluid flow and controlling fluid flow systems. The invention uses a magnetically responsive float normally resting in contact with a stop element positioned in the flow conduit, with magnetic means positioned upstream. The requisite increase of magnetic force to pull said float element from the stop element against the direction of fluid flow is related to the flow rate, thus serving to indicate same for metering or control purposes. Normally, the current to an electromagnet required to overcome the force of fluid flow is used as a measure of flow rate. This system can also be employed to determine fluid viscosity.

Electromagnetic flowmeter usable in less-than full fluid lines

Abstract: An electromagnetic flowmeter having a flow tube which is interposable in a normally less-than-full fluid line. A pair of arcuate electrodes are mounted in the flow tube at opposed positions therein to span a substantial portion of the total tube circumference, whereby they are operative with respect to fluid in the tube in a range extending from a level close to empty to a level close to full. Associated with the flow tube is an electromagnet that is excited by a periodically-interrupted direct current to establish a magnetic field in the tube which is intercepted by the fluid passing therethrough to induce a signal in the electrodes. This signal is sampled during the steady state intervals of the magnetic flux to provide an output free of zero-shift error and of interference voltages. The flux distribution is such as to progressively decrease in intensity as one goes from the top to the bottom of the tube to provide an output signal which is indicative of flow rate and is independent of the liquid level so that an accurate reading of flow rate is obtained regardless of the level of fluid in the flow tube.

Electronic control for constant and variable volume central heating and air-conditioning systems

Abstract: A control system for use in central heating and air-conditioning installations to control the volumetric flow rate of conditioned air through a supply duct to an enclosed space to be serviced. The system is adapted to maintain a desired ambiant temperature in the enclosed space by regulating the circulation of conditioned air in accordance with the demand generated by prevailing conditions. An adjustable restrictor valve defining an orifice is located in the supply duct and sensors are provided to continuously measure the orifice diameter and the pressure drop across the orifice. Electronic circuitry is provided to generate a flow rate voltage signal representative of the product of the orifice diameter and the pressure drop across the orifice and to compare the flow rate voltage level with a fixed or temperature controlled reference voltage to obtain either an "increase" or "decrease" control voltage signal. An "increase" control signal is used to enlarge the orifice diameter and increase the volumetric flow rate while a "decrease" control signal is used to decrease the flow rate and reduce the orifice diameter.

Behind casing water flow detection using continuous oxygen activation

Abstract: Measurement of the volume flow rate and linear flow velocity of undesired behind casing water flow is provided. A well tool having a 14 MEV neutron source is used to continuously irradiate earth formations behind well casing. The continuous neutron irradiation activates elemental oxygen nuclei comprising the molecular structure of any undesired water flow to be detected. Dual spaced gamma ray detectors located above or below the neutron source detect the decay of unstable isotope nitrogen 16 and from these indications the linear flow velocity of the undesired water flow is deduced. By then estimating the distance R to the undesired flow region the volume flow rate V may be deduced.

Ultrasonic flow meter

Abstract: In an ultrasonic flow meter for measuring the flow rate of a fluid flowing through a pipe by determining the frequency difference between ultrasonic waves traveling within the fluid in the direction of flow of the fluid and in a direction opposite thereto, respectively Each of the ultrasonic transmitters and receivers is connected to the pipe through an individual guide rod having disposed on its outer surface ridges which are adapted to cause ultrasonic waves reflected from the ridged surface to conceal one another out, and a thin gold sheet interposed between the guide rod and the pipe

Device for measuring the mass flow or flow rate of a gas

Abstract: A device for measuring the mass flow or flow rate of a gas which entrains ions produced by an electrode positioned in the path of the gas flow, this electrode being brought to a certain potential with respect to at least one other electrode also arranged in the flow path.

Dynamic Response of Settling Basins

Abstract: The flow rate and sediment concentration of inflow into settling basins usually vary with respect to time; thus the sediment concentration of effluent also varies following these variations. This sediment concentration variation of settling basin effluents was analyzed theoretically by a lumped-parameter model. The resuspension of deposits from the bottom of the basin by scouring was taken into account in the computation of effluent concentration. Some numerical calculations are carried out and the results prove that the flow rate of settling basins should be carefully controlled because if the volume of water in the basin decreases greatly the sediment concentration in effluent increases sharply.

Device for bypassing flow rate pulsations around a flow rate transducer

Abstract: A device for bypassing flow rate pulsations resulting in reverse flow and abrupt flow rate surges around a volumetric flow rate transducer includes a housing defining a chamber. One end of the chamber is coupled in fluid communication with the inlet or upstream side of the transducer while the other end of the chamber is coupled in fluid communication with the outlet or downstream side of the transducer. A flexible, fluid impervious diaphragm is mounted in the housing so as to divide the chamber into two compartments. The diaphragm is affixed to the walls of the chamber so as to maintain a fluid seal between the two compartments of the chamber. When a forward flow rate pulsation occurs the resultant rise in the fluid pressure differential between the upstream and downstream compartments of the chamber will shift the diaphragm toward the downstream compartment. As the diaphragm moves, fluid is forced out of the downstream compartment and into the fluid stream on the downstream side of the transducer. After the pulse reaches its maximum and the flow begins to reverse, the reverse flowing fluid will drive the diaphragm back toward the compartment coupled to the upstream side of the transducer. As this occurs, the volume of the fluid that was driven into this chamber during the flow rate increase is exhausted from the upstream side of the chamber and is driven into the fluid stream upstream of the transducer. The net effect of the operation of the pulsation bypass device is to allow flow rate pulsations resulting in reverse flow to pass through the diaphragm, isolating the flow transducer from the pulsations by allowing the diaphragm to flex against the biasing spring and time averaging the flow through the transducer. Thus, the transducer is not exposed to sudden increases or decreases in flow rate.

Experimental Study of Steady-State Boiling of Sodium Flowing in a Single-Pin Annular Channel

Abstract: An experimental study was carried out on steady-state boiling of sodium flowing in the annular channel formed around an electrically heated simulation of a fuel pin. In the present experiment, the inlet temperature and flow rate were held constant, and the heat flux was gradually increased up to the inception of boiling. Thereafter, the heat flux was further increased step by step until the surface temperature of the heater pin marked a sharp rise, indicating the occurrence of dry-out. Records were obtained of the changes brought by the increasing heat flux to boiling phenomena, with particular reference to the behavior of the two-phase flow pattern and to the characteristics of boiling noise, as well as of the frequency of bubble formation. It was made clear that there exists a region in which steady-state boiling will be established, and under these conditions the two-phase flow pattern changes sequentially from bubbly flow to slug flow and then to annular flow. This behavior of sodium boiling in a narr...

Flow of a newtonian fluid between parallel flat permeable plates—the application to a flat-plate hemodialyzer

Abstract: The problem of the creeping flow of a Newtonian fluid between parallel flat permeable plates is considered. It is assumed that the transboundary seepage takes place in accordance with a relationship proposed by Darcy for flow through a permeable medium and that both plates are associated with filtration coefficients of equal magnitude. Exact closed-form solutions for the pressure and velocity fields are presented, and equations describing the axial variation of the mean cross-sectional pressure, the axial volumetric flow and the transmural flux are derived. Approximate solutions valid for small seepage rates are given. The solutions are applied in a discussion of the rate of ultrafiltration in flat-plate hemodialyzers.

Fluid flow between rotating cylinders

Abstract: Fluid flow between a pair of rotating cylinders with non-equal sized rolls and/or non-equal speeds of the rolls is considered for aNewtonian fluid at constant temperature. The lubrication approximation is applied as usual in the theory of calendering. A theoretical analysis of the velocity-, pressure- and shear stress distributions in the flow field is given. Processing parameters as volumetric flow rate, total power required to drive both rolls, and roll-separating forces are calculated and described in terms of the geometrical and kinematical parameters of the system.

Well fluid production profiling using an oxygen activation flow meter

Abstract: Measurement of undesired water cut volume flow rate in a producing well is provided. A well tool having a 14 MEV neutron source and dual spaced gamma ray detectors is used to activate elemental oxygen comprising the molecular structure of the undesired water cut. The tool is moved through the perforated zone with detectors located first above and then below the neutron source. The linear flow rate of water from casing perforations in an upward or downward direction in the casing is detected and by combining this with a prior knowledge of the casing cross sectional area, a volume flow profile of production of water flow from each set of casing perforations is constructed.

Behind casing fluid flow detection in producing wells using gas lift

Abstract: Methods are provided for locating and measuring the linear flow velocity and volume flow rate of undesired water production behind casing in a producing well operating on gas lift while the well remains in a producing configuration. A well logging tool sized and adapted for passing through production tubing is lowered through the tubing string into the producing zone. The tool contains a source of 14 MEV neutrons and two longitudinally spaced gamma ray detectors. The detector may be placed alternately above or below the neutron source on the tool while maintaining the same source to detector spacing. With the well on production under gas lift the earth formations behind the casing are irradiated with 14 MEV neutrons, either continuously or in bursts, to activate elemental oxygen nuclei comprising the molecular structure of the undesired water flow. The decay of unstable isotope nitrogen 16 produced thereby is detected by the detection of its characteristic gamma rays at the dual spaced detectors. These measurements may then be interpreted in terms of the linear flow rate and volume flow rate of the undesired water flow.

Apparatus for monitoring two-phase flow

Abstract: A method and apparatus for monitoring two-phase flow is provided that is particularly related to the monitoring of transient two-phase (liquid-vapor) flow rates such as may occur during a pressurized water reactor core blow-down. The present invention essentially comprises the use of flanged wire screens or similar devices, such as perforated plates, to produce certain desirable effects in the flow regime for monitoring purposes. One desirable effect is a measurable and reproducible pressure drop across the screen. The pressure drop can be characterized for various known flow rates and then used to monitor nonhomogeneous flow regimes. Another useful effect of the use of screens or plates in nonhomogeneous flow is that such apparatus tends to create a uniformly dispersed flow regime in the immediate downstream vicinity. This is a desirable effect because it usually increases the accuracy of flow rate measurements determined by conventional methods.

Fluid flow measuring apparatus

Abstract: Apparatus for measuring the rate of fluid flow through a conduit including a flow rate sensor assembly connected to suitable electrical circuitry and indicating instrumentation. The sensor assembly includes a heated wound resistive element which senses fluid flow rate and a fluid temperature compensating wound resistive element, both elements being mounted on a common spherically shaped surface which is exposed to the flow media.

Volume Flow Measurements

Abstract: The experimental approaches applied in volume flow measurements (the theoretical implications of these are described in section 4.2.) are summarized in the following scheme: 13.1. Volume flow between cell and its surroundings 13.1.1. Determination of volume flow from cell weight changes 13.1.2. Estimation of cell volume a) direct measurement of cell diameter or thickness b) measurement of the volume of cells packed by centrifugation c) optical methods 13.2. Transcellular volume flow and flow across cell layers 13.2.1. Determination based on the change of concentration of an impermeant substance 13.2.2. Determination based on weighing 13.2.3. Determination based on direct volume measurement a) apparatuses with calibrated vessels and capillaries b) automatic maintenance of volume in one compartment