Water Volumetric Flow Rate Research Articles

The structure of two-phase grid turbulence in a rectangular channel: an experimental study

Measurements in two-phase, water–air bubble, grid turbulence have been conducted in a vertical water channel of square cross section. The water flow was directed upwards. A 30 mm mesh grid located at the entrance of the test section generated, in the absence of the dispersed phase, a nearly isotropic turbulent flow field occupying the central part of the channel. Air bubbles were injected in the flow from the grid. Velocity measurements of the liquid phase were obtained using Laser Doppler Velocimetry. The measured flow characteristics included mean velocity and statistical quantities such as turbulence intensity, probability distribution function, skewness and flatness factors, autocorrelation, macroscale and power spectra, for both the longitudinal and transverse velocity components. Local void fraction was measured with an optical probe as well as with hot film anemometry. Bubble velocity and size were estimated with photographic techniques. Presented measurements illustrate the upwards development of void fraction distribution at successive cross sections of the channel. The observed distributions indicate the presence of a mechanism responsible for capturing and redistributing the bubbles. Accordingly, physical mechanisms possibly responsible for the observed phenomenon such as a Segre–Silberberg effect, modified for deformable bubbles in the presence of buoyancy, or the action of large eddies present in the flow are discussed. The velocity field has been obtained on a cross-section at a distance of 30 mesh from the grid at a constant water volumetric flow rate. Based on the obtained experimental results, the influence of the dispersed phase on the initially isotropic turbulence field is identified and the physical processes responsible for the observed changes are discussed. The presence of the second phase appears to introduce inhomogeneities in the void fraction and flow property distributions leading to the emergence of two spatial regions controlled by different physical processes. Also, two distinct regimes in the measured quantities are observed, corresponding to low and high values of gas flow rate ratio. The described changes result in a significant departure from initial isotropy, followed by a tendency towards returning to a state characterised by nearly normal probability distributions and scales close to that of grid turbulence as the gas flow rate increases. Finally, the measured autocorrelation and power spectra offer information regarding the nature of the energy exchanging mechanism occurring between the liquid and dispersed phase.

Flow rate measurement by kinematic wave detection in vertically upward, bubbly two-phase flows

This paper describes a technique for measuring the flow rates of both phases in one-dimensional, vertically upward, bubbly oil–water flows. Measurements of the speed of naturally occurring kinematic waves, obtained using an impedance cross-correlation flow meter, were combined with measurements of the disperse phase volume fraction and an appropriate kinematic wave model to yield predictions of the flux density of both the oil and the water. A systematic error of −3.16%, and an additional random error with a standard deviation of 2.58%, was observed in the predicted oil flux density (and the predicted oil volumetric flow rate). A systematic error of +4.41%, and an additional random error with a standard deviation of 4.83%, was observed in the predicted water flux density (and the predicted water volumetric flow rate). The impedance cross-correlation flow meter has no moving parts and is of robust construction, making the technique described here suitable for implementation in vertical oil wells.

An Analytical Solution for Contaminant Transport in nonuniform Flow

We obtain an analytical solution for two-dimensional steady state mass transport in a trapezoidal embankment in a spatially varying velocity field through its replacement with a hydro- logically equivalent rectangular embankment. Application of the Dupuit approximation and conform transformation allow for computation of the concentration field in the resulting rectangle in the com- plex potential plane. The latter allows deriving expression for the mass flow rate of contaminants, which is analogous to the Dupuit-Forchheimer discharge formula for volumetric water flow rate. Numerical simulation of advection-dispersion in the actual domain compares favorably with these analytical results, and provides limits of the ratio between transverse and longitudinal dispersivities within which the Dupuit approximation is applicable to mass transport problems.

Slow-flow measurements and fluid dynamics analysis using the Fresnel drag effect

We have employed a Sagnac interferometer to measure small optical phase shifts induced by the Fresnel drag effect on moving media. The system detects volumetric flow rates of water as slow as 43 µL/min while maintaining a small pressure drop across the measuring pipe. Velocity profiles and turbulence measurements of flowing water are also demonstrated and discussed.

Volumetric Flow Rate Comparisons for Water and Product on Pasteurization Systems

A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20°C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.

A comparison of oil-water slip velocity models used for production log interpretation

The accuracies of five slip velocity models that can be used to interpret production logs in oil-water flow have been examined using the flow loop data of Davarzani and Miller. Optimal values of the constants used in the models were determined for each model; the abilities of each model to predict oil and water volumetric flow rates from measured values of water holdup and mixture velocity were then tested. The empirical model of Nicolas and Witterholt performed the best of the models tested.

Abwasserreinigung bis zur Rezyklierungsfähigkeit des Wassers

AbstractWaste water treatment for recycling quality. Treatment of industrial waste water is the most effective measure to be taken for the protection of surface waters. This ecological aim must be combined with the economic constraints of industry by designing the industrial process in such a way that production of harmful substances is reduced to an absolute minimum, that transfer of these substances into the carrier fluid, i.e. water, is limited, and that the volumetric flow rate of water required for the overall process is also reduced to the minimum. However, even when all these possibilities which modern process technology offers are successfully applied, a certain amount of harmful substances will still remain in the effluent, causing damage to the environment. This can in the long run only be prevented by developing closed loops for the process water, which include a waste water treatment process, in which mechanical, biological, and physico‐chemical stages are integrated.

Air Voids at Downshaft‐tunnel Bends

In closed conduit water flows containing a small amount of free air, an air void can form at a bend which connects a vertical shaft to a horizontal tunnel. A sudden reduction in the water flow rate can cause this void to vent back up the shaft. Tests were conducted on eight perspex pipe bends whose center‐line radius varied from 0.5 times–1.5 times the pipe diam, and over a range of pipe diameters from 2.8 in.–7.5 in. (0.072 m–0.190 m). The air volumetric flow rate was up to 2% of the water volumetric flow rate. A combined theoretical and analytical approach yielded equations which can be used to predict void formation and venting at a downshaft‐tunnel bend. Extrapolation of the results shows that these voids will not occur in large diameter bends with moderate air flows.

The effect of temperature on the measurement of water volumetric flowrate using a rotameter

The authors describe how a quadratic function in scale reading and a linear function in temperature, over the range 20-90 degrees , adequately represents the flowrate of water measured with a rotameter.

A recycle flow flotation machine model

Residence time measurements were made on a Denver laboratory flotation machine with and without the DR ring assembly. Soluble and insoluble tracers were used (a dye and fine quartz, respectively), and the variables studied were tank liquid volume, V , water and air volumetric flow rates, Q and Q A respectively, and some geometric and design variables. By analogy with nominal residence time, t N (= V Q ) , a term “effective residence time” t E is defined by: f(t)= exp[− t t E where f( t) is the fraction of tracer remaining in the tank at time t. Perfect mixing is indicated if and only if: (i) data satisfies the exponential relationship; and (ii) t E t N = 1 . Using the soluble tracer the machine behaved substantially as a perfect mixer under all operating conditions, except with the DR ring at values of Q A nearly double the natural aeration capacity of the machine; condition (i) above was satisfied, but t E t N ∼ 1.1 . With the insoluble tracer the machine behaved as a perfect mixer only without air. As Q A increased, t E t N increased from unity to about 1.2, and the effect was emphasized by the DR ring. In all cases condition (i) above was satisfied. A model in which the flow pattern in the tank includes a large component of pulp recirculation through the impeller region is developed. This model can account for the experimental findings but the details remain to be elucidated.

Experimental study of effect of gas injection on rate of mass transfer from solid to liquid

diameter of pellet, ft ; volumetric flow rate of gas, ft3/h fta; mass transfer factor based on liquid flow in two phase flow, dimensionless ; mass transfer factor in single phase flow, dimensionless; mass transfer coefficients based on water flow in two phase flow, lb/ft8 h; mass transfer coefficients of single phase flow, lb/ft2 h; mass velocity of water, lb/h ft2; volumetric flow rate of water, ft3/h ft2; Sherwood number, dimensionless ; G,/L,, dimensionless; temperature, “F; void fraction, dimensionless; viscosity of liquid.