Pressure coupling

Because any such behavior causes the motor to fail in its mission objective, these peculiar operational effects have received considerable research attention. The results of these research studies have shown that these various forms of instability result from a coupling between the transient combustion characteristics of the propellant and the transient ballistics of the combustion chamber. These instabilities are termed pressure-coupled, velocity-coupled, and bulk-coupled, and will be described below. 

The most important parameter in the analysis of pressure-coupled combustion instability is the acoustic admittance Y, which is the ratio of the amplitude of the acoustic velocity V to the amplitude of the acoustic pressure amplitude of the acoustic velocity V to the amplitude of the acoustic pressure P ... 

Church s equations, 176-177 Combustion instability, 52-57 bulk-coupled, 56-57 pressure-coupled, 52-55 velocity-coupled, 55-56 steady-state, 29-51 prediction, 30 pressure plateaus, 34 propellants, 31-50 termination, 57-64 depressurization, 58-62 fluid-injection, 63-64 L, 62-63... 

Acoustic structure functions for pressure coupling in an open-closed tube, for the fundamental and first harmonic. 

Anticipating that the functions Tr and G will be of order unity, it is immediately obvious that the growth rate in Equation 5.1.22 is greater than that of the pressure coupling mechanism Equation 5.1.17 by a factor c/Si (the inverse of the Mach number of the flame). The response function, Tr, is given by [46] ... 

The present study is to elaborate on the computational approaches to explore flame stabilization techniques in subsonic ramjets, and to control combustion both passively and actively. The primary focus is on statistical models of turbulent combustion, in particular, the Presumed Probability Density Function (PPDF) method and the Pressure-Coupled Joint Velocity-Scalar Probability Density Function (PC JVS PDF) method [23, 24]. 

Use of ethanol as a co-solvent with SC-CO2 enhances the extraction of cholesterol from dried muscle foods. High extraction pressure coupled with multiple separation vessels for gradual reduction of SC-CO2 density reduces the separation time necessary for separating cholesterol from beef tallow using less CO2 than extractions at lower pressure. Ethanol is a good co-solvent used with SC-CO2 for separating cholesterol from other lipids in beef tallow. 

Schmidt et al. (102) carried out a detailed experimental study of PET blow molding with a well-instrumented machine and compared the results with theoretical predictions using FEM and an Oldroyd B constitutive equation. They measured and calculated internal gas pressure, coupled it with the thermomechanical inflation and performed experiments and computations with free parison inflation. 

Table II contains a summary of selected potassium vaporization data for these systems. With a few noted exceptions, the oxygen partial pressures coupled stoichiometrically with potassium, in keeping with reaction [3]. Hence, K20(A) activities can be derived, to a good to excellent approximation, using the corresponding dissociation-pressure data for pure liquid KgO. That is.

The pressure coupling term has the same magnitude but the opposite sign in the continuous and the dispersed phase momentum equations, which implies a transfer of momentum between the phases. The correlation between the fluctuating hold-up and fluctuating pressure can be modeled as follows (Appendix A) ... 

A rise in blood pressure coupled with renal adverse effects has been reported. Coronary artery spasm leading to myocardial infarction was described as part of an allergic reaction with Quincke s edema (SED-11, 190) (3). 

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