Gas jet velocity

System temperature and pressure affect the momentum of grid jets via the gas density (see Ch. 2). The momentum of the gas jets is p AC/A. When the temperature is increased, the gas density decreases. For the same gas jet velocity this decreases the momentum of the jets and, therefore, decreases the jet penetration and the attrition at the grid. Similarly, when system pressure is increased, gas density increases, gas jet momentum increases and, therefore, the jet penetration and the attrition at the grid are increased. 

Velocity attained by a rocket at the moment at which combustion ceases. It is a function of the -> Gas Jet Velocity, the -> Mass Ratio, and the burning time. 

The function of the nozzle in rockets is to produce fast flow-through of the gas (- Gas Jet Velocity) by constricting the cross-section. The gas jet flows in the nozzle throat at the speed. 

In rocket technology, the ratio between the burning surface of the propellant and the smallest cross-section of the nozzle. It determines the resultant pressure in the combustion chamber of the rocket (other relevant keywords -> Burning Rate, - Gas Jet Velocity - Rocket, Solid Propellant Rocket, Specific Impulse, - Thrust). 

For more details on this subject, see Barrere, Jaumotte, Fraeijs de Veubeke Vandenkerckhove Raketenantriebe. Elsevier, Amsterdam, 1961. Also Dadieu, Damm, Schmidt Raketentreibstoffe Springer, Wien 1968 also -> Gas Jet Velocity and -> Thermodynamic Calculation of Decomposition Reactions. 

The particle tracking is therefore divided into two phases. In the first the acceleration within the fast gas jets that are found in and just above the erupting bubbles is simulated and in the second the accelerated particles are followed through the freeboard. In practice this means an average gas jet velocity and the time and distance the particle spends within that jet are estimated from the fluidised bed model, and then put into the particle tracking model. This gives an initial particle velocity for tracking... 

Gas jef mixing noise consisfs of a broadband frequency spectium. The frequency af which fhe spectium peaks depends on several factors such as fhe diameter of the nozzle, Mach number of fhe gas jef, fhe angle of the observer s position relative to the exit plane of the jet, and temperature ratio of the fully expanded jet to the ambient gas. In the flare and burner industry, gas jet mixing noise typically peaks somewhere between 2000 and 16,000 Hz. The characteristic shape is the same for all temperatures and angles, although there is a significant dependence on temperature and Mach number of fhe gas jef when the observer is positioned at an angle of less fhan 50° off axis from the centerline of the gas jet velocity vector [11]. 

Typically, pulse combustors oscillate with frequencies that vary from 20 to 150 Hz. Pressure oscillations in the combustion chamber of 10 kPa produce tailpipe velocity oscillations of nominally 100 m/s and the gas jet velocity at the tailpipe exit pulsates from approximately 0 to 100 m/s [27]. The input power for commercially available pulse combustors ranges from 70 to 1000 kW. 

Deciding on grid design parameters such as hole size and the gas jet velocity required to achieve a certain jetting region. 

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