Showing papers on "Mass flow published in 1976"

The interfacial drag and the height of the wall layer in annular flows

Abstract: A method to predict the height of the wall layer and the interfacial drag in annular flow under conditions that the flow rate of the entrained liquid is known is developed from measurements on air-water flow in circular tubes. Flow conditions are found to be characterized by a generalized Martinelli flow parameter.

The Dynamic Transfer Function for a Cavitating Inducer

Abstract: Knowledge of the dynamic performance of pumps is essential for the prediction of transient behavior and instabilities in hydraulic systems; the necessary information is in the form of a transfer function which relates the instantaneous or fluctuating pressure and mass flow rate at inlet to the same quantities in the discharge from the pump. The presence of cavitation within the pump can have a major effect on this transfer function since dynamical changes in the volume of cavitation contribute to the difference in the instantaneous inlet and discharge mass flow rates. The present paper utilizes results from free streamline cascade theory to evaluate the elements in the transfer function for a cavitating inducer and shows that the numerical results are consistent with the characteristics observed in some dynamic tests on rocket engine turbopumps.

Chemical tracer method of and structure for determination of instantaneous and total mass and volume fluid flow

Abstract: The method of determination of the total mass flow of at least one component of interest in a reacted flowing main fluid in a period of time comprising the introduction of an analyzable tracer component at a known mass rate into a flowing main fluid, mixing the tracer component with the flowing main fluid, reacting the mixture of the tracer component and flowing main fluid in a reactor, analyzing the reacted mixture to determine the concentration of at least the tracer component and one component of interest in the reacted mixture, and time integrating the product of the ratio between the component of interest concentration and the tracer concentration, and the mass flow rate of the tracer over the time period. The fluid flow rate of the reacted flowing main fluid may be slowly changing and the component of interest may be a reacted fuel which may be a fossil fuel or a reaction product thereof or of the flowing main fluid.

System for determining the ratio of oil to water in a metered fluid stream

Abstract: A system for metering a fluid stream constituted by a mixture of oil and water to determine the volumetric ratio of oil-to-water in the stream. The system includes a vortex meter through which the stream is conducted to produce a meter signal whose frequency depends on the volumetric flow and whose amplitude depends on the mass flow of the stream. Derived from the meter signal is a volumetric signal that is solely a function of frequency and a mass flow signal that is solely a function of amplitude, the volumetric signal being divided by the mass flow signal to produce a density signal. The volumetric and density signals are fed to a computer to which is also applied a temperature signal that depends on the temperature of the metered stream. The computer has stored therein the relationship between water density and temperature and that between oil density and temperature, and it functions in response to the signals applied thereto to determine the respective volumes of oil and water in the mixture.

Flame-Spreading and Combustion in Packed Beds of Propellant Grains

Abstract: This paper is concerned with the prediction of the pressure history during the process of flame-spreading and combustion of solid-propellant grains as would occur, for example in a gun cartridge. Solution of the governing conservation equations for the two-phase media requires the use of empirical relations to account for the physical processes of momentum and energy interaction between the solid grains and hot propellant gas. The results indicate the extreme importance of these interaction relations on the predictions of the pressure and velocity field. and at the other is a projectile which will begin to move at a given prescribed pressure. This '"piston" then moves through a long length of channel of the same cross section as the cham- ber, in order that the flow processes following piston motion can be followed. A predescribed igniter mass flow provides gaseous products which, in turn, ignite the bed. Since solid propellants have high burning rates, the rate of gas generation within the chamber is high. Therefore, the pressure is rising rapidly during this flame-spreading process. The pressure rises enhances the pressure-dependent burning rate of the propellant, the result of which is a rapidly accelerating combustion process, with generally steep gradients along the length of the chamber. This gradient results in a high-velocity flow of the gases toward the piston end and into the unburned portion of the propellant. Hence, the flame-spreading and pressurization is rapid, and the entire burn is completed in a matter of milliseconds, if the ignition source is strong enough. Looking at flow process taking place, one may determine the effect on the particle bed. The hot igniter gases initially are driven into a quiescent bed of propellant particles. These ignite the particles nearest the igniter source. The mass generation and subsequent pressurization occur, and a flowfield develops within the chamber. The propellant par- ticles exert a drag force on the flowing gases and are ac- celerated. As shot-start pressure is approached, the entire bed usually has been set into motion.J Throughout the burn, the particles continue to decrease in size as they burn. Kuo and Summerfield2 have pioneered the analysis of packed-bed solid-propellant combustion.

Second‐order slip effects in Poiseuille flow

Abstract: Plane Poiseuille flow of a rarefied gas was studied in the presence of both a pressure and a temperature gradient under near continuum conditions. Calculations are performed for general gas–gas and gas–surface interactions of the molecules. The second‐order slip and the phenomenological coefficients of the symmetric Onsager matrix were explicitly calculated by variational techniques. The slip velocity and the contributions of the Knudsen layer to mass and heat flows are described by a second symmetric matrix.

Method and apparatus for measuring mass flow rate of individual components of two-phase gas-liquid medium

Abstract: A method for measuring the mass flow rate of individual components of a two-phase medium comprises feeding a flow of a medium to be measured through a hollow pendulum, imparting undamped oscillations to the pendulum, measuring energy required to maintain a constant oscillation velocity, the mass flow of the medium being assumed proportional to the measured energy value and the average density of the medium being assumed proportional to the measured fundamental frequency of the pendulum, and determining mass flow of each component from mathematical relationships An apparatus for carrying out the method for measuring mass the flow rate of individual components of a two-phase medium comprises a sealed housing accommodating a hollow pendulum supported therein The housing mounts an electromagnetic coil for imparting undamped oscillations to the pendulum and an electromagnetic coil for converting oscillation velocity Output frequency signals of converters are proportional to the mass flow rate of the two-phase medium and to the density of the two-phase medium being measured

Method of powder coating the interior of tubular goods

Abstract: The interior of a pipe is coated with a uniform thickness of plastic. A fluidized bed of heat-meltable plastic material in particular form is connected to the inlet end of the pipe, while the opposed end of the pipe is made attachable to a source of reduced pressure. A source of compressible fluid is also connected to the inlet end of the pipe. The pipe is preheated and then rotated axially while the compressible fluid flows therethrough. The compressible fluid flowing to the inlet is suddenly terminated while a flow from the fluidized bed is immediately established so that the vacuum at the outlet end of the pipe causes uninterrupted mass flow and pulls a finite pocket of the finely divided plastic into the pipe. The flow of particular plastic material is terminated, while the flow of compressed gas is immediately re-established, thereby pushing the pocket of plastic material into and through the pipe.

Gas turbine jet propulsion engine

Abstract: A gas turbine engine has three turbines, the intermediate and high pressure turbines running at substantially constant corrected speed. The low pressure turbine has variable nozzle guide vanes and the low pressure compressor has variable stators so as to enable its speed to be varied, while its mass flow is arranged to be large at low speeds.

Mass flow sensor system

Abstract: A mass flow sensor system for measuring the flow rate of a fluid in a sensing tube at diverse angular attitudes. Output signal distortion is minimized by neutralizing the effects of convection forces. The sensing tube is formed as a by-pass coupled to a fluid conduit and includes a loop in the shape of a single-turn helix. Circulation of the fluid through the loop cancels gravity-induced convection forces caused by temperature gradients and significantly reduces sensitivity to attitude change. A center-tapped temperature-sensitive resistor coil is wound around the outer surface of the loop. The coil is heated, and the temperature differential between the ends of the coil, corresponding to rate of mass flow, is detected as a voltage output signal generated in an associated bridge circuit.

Method of and apparatus for controlling combustion

Abstract: A liquid or gaseous (fluid) combustible is mixed with a combustion-sustaining gas and fed under pressure into a chamber where the mixture is burned. The mass flow of the combustible (fuel) is normally maintained constant for a combustion chamber of given thermal power output. The pressure in the chamber is continuously detected and the ratio of the mass flow of recirculated exhaust gas to the mass flow of the oxygen-containing gas (air or oxygen), which together constitute the combustion-sustaining gas, is increased when this pressure increases above a predetermined limit and the ratio is decreased when the pressure decreases below a predetermined limit. The ratio is varied by increasing or decreasing the proportion of exhaust gases and thereby decreasing or increasing, respectively, the partial pressure of oxygen in this combustion-sustaining gas.

Diffusion and Mass Flow of Nitrate-Nitrogen to Plant Roots1

Abstract: The transport of plant nutrient ions from the soil mass to plant root surfaces is an important phenomenon in mineralnutrition of plants. Nitrate-nitrogen, the most important source of nitrogen of non-leguminous plants, is soluble in soil water and is transported to plant roots by both mass flow and diffusion. It is, therefore, important to understand the relative importance of each of these two mechanisms of transport of NO₃-N to plant roots and the environmental conditions under which each is the dominant mechanism of transport. In order to predict from theory the simultaneous transport of NO₃-N to plant root, several soil and plant parameters must be known. These parameters include the volumetric soil water content, concentration of NO₃-N in soil solution, porous diffusion coefficient of NO₃-N in soil, average macroscopic velocity of soil water at plant root surface, radius of root, transpiration rate and plant root length. These soil and plant parameters must be measured in either the field or greenhouse. The validity and/or consequences of several assumptions of a previously reported steady-state model describing simultaneous mass flow and diffusion of NO₃-N to plant root surfaces are discussed with reference to experimental measurement of plant and soil parameters. The relative importance of diffusion to mass flow of NO₃-N is large when the ratio of transpiration rate to the constant of proportionality relating flux into the plant to concentration of NO₃-N in the soil solution is less than 0.2 but is negligible when the ratio is greater than unity. The average concentration of NO₃-N of the entire soil mass rather than the concentration of NO₃-N at the outer radius of the soil cylinder associated with each root can be used in the model with little error for most situations expected to occur in the field.

Numerical modeling of cyclic storage of hot water in aquifers

Abstract: The LBL numerical model used is called CCC which stands for Conduction, Convection, and Compaction. The model computes heat and mass flow in three-dimensional water saturated porous systems. Concurrent with the mass and energy flow, the vertical deformation of the geothermal system is simulated using the one-dimensional consolidation theory of Terzaghi. Thus the following physical effects can be included simultaneously in the same calculation: (1) flow of hot and cold water with large viscosity and density differences; (2) effects of temperature on fluid heat capacity, viscosity, and density; (3) heat convection and conduction in the aquifer; (4) heat exchange between the porous aquifer and its contained fluids as well as with the confining beds; (5) effects of regional groundwater flow; (6) combined effects of many injection and withdrawal cycles; (7) spatial variations in aquifer properties; and (8) possible compaction and the associated land subsidence due to pressure changes during the injection-withdrawal history. The paper we have concentrates on a detailed calculation of the mass and energy flow and leaves the problem of compaction and subsidence to a later study. (TFD)

Aerodynamic flow body

Abstract: Disclosed is an increased lift aircraft or similar device having an airfoil shaped forward structure. A mass flow engine, such as a jet engine, is positioned to the rear of this structure. In operation, the intake air flow for the engine flows around the forward structure, generating lift.

Study of the boundary layers in chemical laser nozzles

Abstract: Chemical laser nozzles, both axisymmetric and two-dimensional, are examined to define the effect of the nozzle geometry and boundary layers on the flow. A method of defining average flow properties, which include the boundary layer influence within a one-dimensional flow formulation, is presented. The boundary layers are found to be of the same order as the nozzle exit dimensions and have a large influence on the flow. Axisymmetric and two-dimensional nozzles with the same inlet flow, geometric area ratios, and nozzle exit dimensions are found to have essentially the same average nozzle exit flow properties; the nozzle mass distributions, however, are quite different and indicate that axisymmetric nozzles may result in faster cavity mixing. Methods of including the boundary-layer influence in the laser performance and pressure recovery analyses are discussed.

Mass flow meter

Abstract: A method and apparatus for determining the mass flow of a fluid using dielectric constant measurements to determine density and converting the velocity of flow to a related frequency. The measurement of both the dielectric constant and frequency are made using a single capacitor.

Aero-engine applications of laser anemometry

Abstract: The measurement of flow inside an aero-engine or component rig is made difficult by the hot, high-pressure environment, problem of access, and the requirement not to disturb the flow. Laser anemometry offers an almost ideal solution to several of these problems and has been used under laboratory conditions for several years. However, because it is extremely difficult to add particles evenly to the very high mass flow involved, methods based on the naturally occurring particles in the flow have been developed and are described here. The information available from the light signal scattered from particles in a flow is examined and a real fringe system with fringe counting or photon correlation is chosen as the most useful processing method for laser anemometry in this situation. Measurements obtained from engine component rigs using a counting system are presented together with measurements from several aero-engines obtained using photon correlation. All results were obtained using a 15-mW HeNe laser.

Dynamic response of cavitating turbomachines

Abstract: Stimulated by the pogo instability encountered in many liquid propellant rockets, the dynamic behavior of cavitating inducers is discussed. An experimental facility where the upstream and downstream flows of a cavitating inducer could be perturbed was constructed and tested. The upstream and downstream pressure and mass flow fluctuations were measured. Matrices representing the transfer functions across the inducer pump were calculated from these measurements and from the hydraulic system characteristics for two impellers in various states of cavitation. The transfer matrices when plotted against the perturbing frequency showed significant departure from steady state or quasi-steady predictions especially at higher frequencies.

Experimental and Theoretical Investigation of Flow Generated by an Array of Porous Tubes

Abstract: A novel scheme of introducing flow into an electric discharge laser (EDL) cavity has been developed and is described here. The flow, which is generated by a grid of parallel porous tubes, has beet studied experimentally and theoretically. Detailed measurements of the flow field structure using hot-wire anemometry have been carried out and some turbulence data obtained near the porous tubes. A theoretical model based on rotational inviscid flow near the porous tubes is developed. The vorticity distribution is chosen to satisfy both the mass flux and no slip conditions on the tube walls. The near field flow exhibits a wake downstream of the tubes. A vorticity diffusion model is introduced to render the flow uniform in the far field. Agreement is shown between experiment and theory.

Transonic Swirling Flow in Axisymmetric Nozzles

Abstract: The transonic flow in axisymmetric choked nozzles is computed in the case of a radial distribution of tangential velocity. The flow configuration is obtained by means of a time-dependent technique. The swirling flow is achieved through a particular surface located at the inlet of the nozzle. The pressure distribution and the sonic line are presented for choked flows without or with swirling.

Boundary layer bleed system study for a full-scale, mixed-compression inlet with 45 percent internal contraction

Abstract: The results of an experimental bleed development study for a full-scale, Mach 2.5, axisymmetric, mixed-compression inlet were presented. The inlet was designed to satisfy the airflow requirements of the TF30-P-3 turbofan engine. Capabilities for porous bleed on the cowl surface and ram-scoop/flush-slot bleed on the centerbody were provided. A configuration with no bleed on the cowl achieved a minimum stable, diffuser exit, total pressure recovery of 0.894 with a centerbody-bleed mass flow ratio of 0.02. Configurations with cowl bleed had minimum stable recoveries as high as 0.900 but suffered range decrement penalties from the increased bleed mass flow removal. Limited inlet stability and unstart angle-of-attack data are presented.

Experiment on MHD generator with a large-scale superconducting magnet /ETL Mark V/

Abstract: E XPERIMENTAL and theoretical investigations were made of the A1203 coated peg-wall-type generator with a large-scale superconducting magnet. In Japan's MHD National Project, the many component apparatuses required for the MHD plant had been developed individually and these apparatuses had been combined into ETL Mark V and VI MHD generators in 1971. The ETL Mark V generator had as main components, a superconductin g magnet, the cold-wall Faraday-type generating channel, and a combustor of 25-MW thermal input for the purpose of investigating the generating characteristics in a strong magnetic field. The details of the ETL Mark V generator were reported elsewhere.l'6 Since the construction of this equipment, 27 thermal and three generating experiments have been carried out and the summary of these operations resulted in about 55 hours of thermal and about five hours of generating experiments. The maximum output power of 86 kW was generated in the first one, 193 kW in the second one, and 482 kW in the last one. This note describes the results of the last generating experiment and experimental conditions are summarized in Table 1. The calculated gas temperatures were 3050K at the combustor and 2680K at the inlet of the generating section for the mass flow rate of 3 kg/sec. Though the combustion conditions were different, the measured gas temperature was 2860K at the inlet of the generating section on the other thermal experiment of 3 kg/sec. The power generating time was 3.3 hrs. The central magnetic field strength was 4.2 T. The generating channel had 50 pairs of electrodes which were made of sintered copper (30%)-tungsten (70%) as cathode and stainless steel (AISI 304) as anode. The estimated surface temperatures of cathode and anode were 600K and 900K, respectively. The electrode surface area was 18x100 mm2 and electrode pitch was 36 mm. The cross-sectional area of the generating section was 150x100 mm2 at inlet and 241 x 100 mm2 at outlet and the length was 1764 mm. The generating characteristics were measured at each step of mass flow rate. The generating channel was constructed with 50 pairs of side and electrode wall modules whose flow direction length was 108 mm.1'2 The heat losses were calculated from measuring the water flow rate and temperature difference of every wall module. The heat loss and the fraction of the thermal input at the mass flow rate of 3 kg/sec were as follows: combustor-2.26 MW, 9.1%, nozzle-3.78 MW, 15.2%, total up to the inlet of the generating section-6.04 MW, 24.3%; generating section- 1.93 MW, 7.8%; downstream up toihediffuser-2.32MW,9.3%. Figure 1 shows the heat flux distribution for the mass flow rates of 2 kg/sec and 3 kg/sec and the calculated value for 3 kg/sec. The position of the nozzle throat was x = 0.7 m; the inlet of the generating section was 0.91 m and the outlet was 2.67 m. The heat flux varied considerably in the case of short

Rigorous constructive solution to monodimensional Poiseuille and thermal creep flows

Abstract: A rigorous constructive method is discussed for solving the linear integral equations which govern either the Poiseuille flow and the thermal creep flow of a rarefied gas between parallel plates. In both cases numerical results are presented for the nondimensionalized mass flow rate, and for certain quantities which are closely related to the mass and slip velocities. Critical comparison with previous results is made wherever possible.