Average gas velocity

Michaelides EE. Motion of particles in gases average velocity and pressure loss. Trans ASME 109 172-178, 1987. 

Tracer Type. A discrete quantity of a foreign substance is injected momentarily into the flow stream and the time interval for this substance to reach a detection point, or pass between detection points, is measured. From this time, the average velocity can be computed. Among the tracers that have historically been used are salt, anhydrous ammonia, nitrous oxide, dyes, and radioactive isotopes. The most common appHcation area for tracer methods is in gas pipelines where tracers are used to check existing metered sections and to spot-check unmetered sections. 

Measurement by Thermal Effects. When a fine wire heated electrically is exposed to a flowing gas, it is cooled and its resistance is changed. The hot-wire anemometer makes use of this principle to measure both the average velocity and the turbulent fluctuations in the flowing stream. The fluid velocity, L, is related to the current, /, and the resistances, R, of the wire at wire, and gas, g, temperatures via... 

It is seen that equations (13) and (15) are very similar to equation (10) except that the velocity used is the outlet velocity and not the average velocity and that the diffusivity of the solute in the gas phase is taken as that measured at the outlet pressure of the column (atmospheric). It is also seen from equation (14) that the resistance to mass transfer in the stationary phase is now a function of the inlet-outlet pressure ratio (y). 

Vo = Average velocity of gas, feet/sec. u, = Terminal settling velocity of particle under action of gravity, feet/sec. gL = 32.2 feet/sec. ... 

Vj = Average velocity of gas, ft/sec tv = Terminal settling velocity of hydrocarbon... 

Figure 5.3.5 displays dynamic NMR microscopy of xenon gas phase Poiseuille flow with an average velocity of 25 mm s-1 and self-diffusion coefficient of 4.5 mm2 s-1 at 130 kPa xenon gas pressure with numerical simulation (A) and experimental flow profiles (B-D) of xenon gas. 

Where Cv -cavitation number P2-downstream pressure Pv- vapor pressure of water p- density of water at 25°C, V0-average velocity near orifice. The diameter of the orifice was calculated using Cv values which was calculated from P2 (downstream pressure), p (density of water), V0 (average velocity near orifice) and Pv (vapor pressure of water) [48]. C02 gas was passed near to Lc zone as shown in Fig. 7.9, where cavities collapse in the cavitation zone. 

The square root of the average of the square of the velocity, vrms, is not the average velocity, but a quantity called the "root mean square velocity. (b) The pressure of the gas does not matter, (c) The identity of the gas is important, because the mass of the molecule is included in the calculation. (Contrast this conclusion with that of the previous problem.)... 

Hydrogen gas and helium gas arc at the same temperature. What is the ratio of the average velocities of their molecules ... 

VL Average net gas peel off velocity into exiting vortex VG Gas outlet velocity... 

According to the Kinetic-Molecular Theory, all gas molecules have the same average kinetic energy (= M2 mu2) at the same temperature, where u is the average velocity. Hence, at the same T ... 

Simulations are then performed for gas bubbles emerging from a single nozzle with 0.4 cm I.D. at an average nozzle velocity of lOcm/s. The experimental measurements of inlet gas injection velocity in the nozzle using an FMA3306 gas flow meter reveals an inlet velocity fluctuation of 3-15% of the mean inlet velocity. A fluctuation of 10% is imposed on the gas velocity for the nozzle to represent the fluctuating nature of the inlet gas velocities. The initial velocity of the liquid is set as zero. An inflow condition and an outflow condition are assumed for the bottom wall and the top walls, respectively, with the free-slip boundary condition for the side walls. 

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