Showing papers on "Volumetric flow rate published in 1983"

Apparatus and methods for measuring fluid flow parameters

Abstract: An apparatus and method for measuring fluid flow parameters operate under conditions wherein the composition of the fluid flow can change rapidly thereby changing the speed of sound within the fluid and wherein the actual flow rate can change rapidly thereby further changing the transit time of acoustic energy traversing an interrogation path within the fluid. The apparatus determines the speed of sound in the fluid and the fluid flow velocity by measuring an upstream and a downstream transit time of acoustic energy within the fluid. The fluid is typically flowing within a conduit, and the transducers for transmitting and receiving the acoustic energy are precisely and carefully installed in the conduit. The measurements also allow an estimate to be made of the average molecular weight of gases passing through the conduit and hence of the mass flow rate of a gas. The measurements are taken at a frequency sufficient to satisfy the Nyquist criterion with regard to the maximum frequencies of interest for the fluid flow parameters being measured. Special techniques are developed for enabling transducer placement in preexisting conduit arrangements wherein access to the conduit is limited.

Modeling and Analysis of Low Pressure CVD Reactors

Abstract: A detailed mathematical model for the hot wall multiple‐disk‐in‐tube LPCVD reactor is developed by using reaction engineering concepts. This model includes the convective and diffusive mass transport in the annular flow region formed by the reactor wall and the edges of the wafers as well as the surface reactions on the reactor wall. In addition, the model describes the coupling of diffusion between and reaction on the wafers. Variations in gas velocities and diffusion fluxes due to net changes in the number of mols in the deposition are also taken into account as are nonisothermal operating conditions. The combined reactor equations are solved by orthogonal collocation. The deposition of polycrystalline Si from is considered as a specific example, and the model is employed in estimation of kinetic rate constants from published reactor measurements. The effects on the growth rates and film thickness uniformity (within each wafer and from wafer to wafer) of variations in flow rates, reactor temperature profiles, and concentration in the feed stream are analyzed. The model predictions show good quantitative agreement with published experimental data from different sources. Finally, recycle of reactor effluent is considered a typical commercial operating conditions, and it is demonstrated that this modification produces higher growth rates and better film uniformity than can be achieved in conventional LPCVD processing.

Evaluation of API RP 14E Erosional Velocity Limitations for Offshore Gas Wells

Abstract: The production of hydrocarbons from underground reservoirs is associated with the flow of a liquid, gas, and/or solid. This flow situation is essentially one of a liquid-gas, 2-phase flow with entrained solid particles. When the fluid flow in a pipe is disturbed due to a local change in direction, a velocity component normal to the pipe wall will be introduced, resulting in repeated impacts on the pipe wall. Erosion damage of the pipe is caused by the repeated bombardment of liquid and solid particles. The erosion damage is enhanced by increasing the production capacity of a given flow system. To avoid potential erosion problems, most oil companies have limited their production rate by reducing the flow velocity to a level below which erosion does not occur. A method for calculating erosion damage as a function of fluid and flow characteristics is proposed. This approach can be used to calculate a limiting flow velocity for any specified allowable erosion rate.

Jet scrubber and method of operation

Abstract: A process for operating a jet scrubber includes inducing gas to flow through a venturi by spraying coarse liquid droplets into the venturi inlet. The liquid is sprayed at the minimum rate needed to pump the gas. Additional liquid is atomized into fine droplets and introduced into the venturi throat. The ratio of combined liquid flow rates to the gas flow rate is substantially greater than the ratio of the minimum liquid flow rate to the gas flow rate. Hydrogen sulfide gas can be cleaned from a gas stream using a Stretford liquid according to the process.

Controller for uniform fluid dispensing

Abstract: A controller for uniformly dispensing fluid onto a substrate in response to movement between the dispensing unit and the substrate has a sensor which senses the rate of relative movement and supplies a signal reflective of the movement to an operation device which in turn generates and supplies a control signal to a regulator. The regulator is positioned in the fluid dispensing system and regulates the flow rate of the fluid to the dispensing unit so that the substrate receives a substantially uniform fluid coating per unit length. The operation device receives the signal from the sensing means and computes the rate of relative movement. The rate of relative movement is then compared to a preselected flow rate signal; and a signal is generated and supplied to the regulator reflective of the comparison between the computed rate of movement and the preselected flow rate signal, so that the flow rate of the fluid varies substantially proportionally to the rate of relative movement between the dispensing unit and the substrate so that the amount of dispensed fluid per unit length of substrate is substantially constant.

Fluid Flow and Mixing Characteristics in a Gas-stirred Molten Metal Bath

Abstract: Fluid flow and mixing characteristics in a molten metal bath are analyzed for inert gas injection through a nozzle at the center of the vessel bottom. It is postulated that the bath consists of two zones: bubble plume zone where gas-liquid mixtures flow upward and annular zone where liquid flows downward. The analysis is made by setting up a steady-state energy balance for the liquid phase. The liquid velocity in the plume zone, the liquid circulating flow rate and the mixing time are calculated for various injecting conditions and correlated as simple functions of gas flow rate, liquid depth and cross-sectional areas of both the plume zone and the vessel. It is found that the cross-sectional area of the plume zone has a significant influence on the circulating flow. Large cross-sectional area of the plume zone is favorable for mixing in the bath. The calculated results of circulating flow rate and mixing time agree with the experimental results obtained previously.

Methods and apparatus for determining flow characteristics of a fluid in a well from temperature measurements

Abstract: The invention relates to method and apparatus for determining the flow rate of fluid in a well over an interval including zones where fluid is exchanged between the well and the formations through which it is bored. A logging sonde is used to measure the temperature of the fluid along said interval, and the flow rate is measured at least at the ends of the interval. Then for each depth, a flow rate value is determined from the measured temperatures and flow rates, and the set of values obtained in this way are recorded.

Apparatus and method for regulating sheath fluid flow in a hydrodynamically focused fluid flow system

Abstract: An apparatus for analyzing particles, adapted to operate continuously even in the absence of particles contained in a sample medium, includes a sensing region and a particle analyzer associated therewith. A fluid flow path, preferably air flow, causes a sample medium with particles therein to flow through the sensing region. Another fluid flow path ensheathes the sample medium with a flowing sheath fluid for hydrodynamically focusing the particles as they pass through the sensing region. The sheath fluid is adapted to flow at a first flow rate compatible with the flow rate of flowing particles. When the apparatus is operating in the absence of a sample medium, the sheath fluid is controlled to flow at a second flow rate, slower than the first flow rate, for collection thereof.

A method of aligning particles in a moving fluid sample

Abstract: A method is provided for aligning particles in a fluid sample 26 which are moving in a direction through a flow cell 10. A sheath fluid 22 also flows through the flow cell 10 parallel to the direction of flow of the sample fluid 26. The flow rate of the sheath fluid 22 or the sample fluid 26 can be adjusted such that the particles are aligned substantially with their minimum cross-sectional area extended transverse to the direction of flow and with their maximum cross- sectional area extended substantially parallel to the width of flow cell 10 and with the centers of mass A, B, C of the particles of fluid sample lying substantially in one plane 120. With the centers of mass A, B, C of the particles of the fluid sample substantially in one plane 120, a microscope 30 can be focused on the one plane to view the particles. In addition, the microscope 30 can be focused on a plane 122 different from the one plane 120 in order to achieve optical separation of the particles.

Flow modifying device

Abstract: A swirler for a gas turbine engine combustor is disclosed for simultaneously controlling combustor flow rate, swirl angle, residence time and fuel-air ratio to provide three regimes of operation. A first regime is provided in which fuel-air ratio is less than stoichiometric, NOx is produced at one level, and combustor flow rate is high. In a second regime, fuel-air ratio is nearly stoichiometric, NOx production is less than that of the first regime, and combustor flow rate is low. In a third regime, used for example at lightoff, fuel-air ratio is greater than stoichiometric and the combustor flow rate is less than in either of the other regimes.

Isokinetic extractive sampling probe

Abstract: A flow-rate proportional (isokinetic) sampling probe provided with two identical axial-flow thermal flow sensors whose outputs are used in a differential manner together with a sampling nozzle flow controller to extract a flow-rate proportioned sample of fluid passing thereby, wherein one flow sensor is used to sense the velocity of the fluid and the second flow sensor is used to sense the velocity of the fluid captured by the sampling nozzle, the area of which is the same as that for the flowing fluid such that the differences between the flow sensor outputs is directly used to control the sample flow rate and maintain an isokinetic condition under a wide range of fluid conditions. Two identical temperature sensors used respectively for the flow sensors to automatically adjust the operating temperature of the thermal sensors as the ambient temperature changes.

The characteristic equation for superplastic flow

Abstract: The characteristic-area concept of steady-state flow is applied to superplasticity. It is shown that the parametric dependence of flow rate upon stress and grain size is satisfied if it is assumed that an interface reaction controls the diffusion fluxes which lead to strain development. The characteristic area is shown to be equal to the product of the grain diameter and the interfacial line-defect spacing.

Flow rate control system

Abstract: A flow rate regulating valve is mounted on a pipe for passing therethrough the fluid to be controlled.The fluid pressure is detected at the primary side and the secondary side of an orifice provided within the pipe. The fluid temperature is also measured in the vicinity of the pressure measuring location. The flow rate is calculated based on the primary and secondary pressures and temperature detected. The degree of opening of the valve is controlled in a direction to decrease the deviation of the calculated flow rate from the flow rate setting in accordance with the deviation and the polarity thereof.

A hot model study on the effect of gas injection upon the melting rate of solid sphere in a liquid bath.

Abstract: A study was carried out on the effect of gas injection upon the melting rate of an ice sphere in a water bath.Heat transfer coefficient was obtained from the experiment in which the melting rate of an ice sphere was measured. The ice sphere was placed in the upward flow generated by the gas injection through an orifice at the bath bottom.The heat transfer coefficient increased with an increase in the gas flow rate, while it was not influenced much by the orifice diameter and vessel shape.An attempt was also made to estimate the heat transfer coefficient and it was found that Whitaker's heat transfer equation was applicable when the average velocity of the upward flow was known. A tracer method and a method based on the energy balance consideration were employed for obtaining the velocity. The latter method involved mainly calculation.

Optical detector cell

Abstract: An optical detector cell (10) for determining the presence of a solute in a sample fluid includes a sample tube (12), inlet and outlet means (30,32) for the sample fluid, and first and second optical waveguides (16,20) for passing a beam of light axially through the sample tube. The detector cell finds particular use in miniature chromatographic and microspec- troscopic applications where a very low volumetric flow of sample fluid is to be analyzed. By providing an optical flow path which is parallel to the fluid flow path, the thickness of the sample examined is maximized corresponding to a fixed sample volume, resulting in the ability to detect low threshold concentrations of solute.

Performance characteristics of a transverse‐flow, oxygen‐iodine chemical laser in a low gas‐flow velocity

Abstract: Performance characteristics are reported for a transverse‐flow, oxygen‐iodine chemical laser which operates at a low level (8 m/s) of linear flow gas velocity using a small size vacuum pump. This is the first time that dependences of laser output power have experimentally been found on Cl2 and I2 flow rates. Output powers in excess of 10 W have been efficiently extracted from a 50×0.5‐cm rectangular flow duct. A total energy of 11 kJ from one gram of iodine has been obtained. The reaction mechanisms associated with the power decrease in high concentrations of I2 are carefully discussed.

Method and apparatus for leak test

Abstract: To measure the leak rate in a transmission partially filled with a transmission fluid but having an air space of unknown volume, air is supplied to the transmission to pressurize the cavity to a preset value. The flow rate of air to the transmission is measured and that rate is integrated in a computer to determine the mass air flow which is proportional to the volume of the air space in the transmission. The decline of pressure in the air space as a result of fluid leakage from the transmission is monitored by the computer and the leak rate is determined on the basis of that rate and the derived volume of the air space.

Solid Composition and Growth Rate of Ga1-xAlxAs Grown Epitaxially by MOCVD

Abstract: The effects of the growth temperature and the total hydrogen flow rate on the solid composition and the growth rate in the MOCVD growth of Ga1-xAlxAs were investigated in detail. It was found that (1) the rate of incorporation of Ga atoms decreased with increasing growth temperature, while that of Al atoms increased up to 780°C and decreased beyond 780°C; (2) an increase in the total gas flow rate had the effect of reducing the boundary layer thickness and lowering the surface temperature of the wafer; and (3) there was no interaction between Ga and Al atoms in the growth of Ga1-xAlxAs. The detailed experimental results are described in this paper.

Dual frequency acoustic fluid flow method and apparatus

Abstract: An acoustic fluid flow meter determines the flow velocity or volumetric flow from a measurement of the phase shift of acoustic signals propagated upstream and downstream along an acoustical path in the fluid. High resolution measurements of the phase difference of transmitted and received signals represent the fractional wavelength which exceeds the integral number of waves along the acoustic path. The low resolution determination of the integral and fractional number of waves for each direction is made by measuring the fractional phase shift at one frequency of the acoustic signal and again at a slightly different frequency of the acoustic signal. The difference of those phase shift measurements is proportional to the number of waves along the path for a given direction of propagation. That value is combined with high resolution fractional phase shift measurement to obtain a high resolution total wave number value for each direction of propagation. The difference of those two values then is proportional to the fluid flow.