Total pressure

About: Total pressure is a research topic. Over the lifetime, 5199 publications have been published within this topic receiving 66658 citations.

Modeling the Pressure Generation in Aluminum‐Based Thermites

Abstract: The paper proposes a new theoretical model based on local thermodynamic equilibrium enabling the prediction of gas generation during the reaction of aluminum-based thermites. We demonstrate that the model has the capability to predict the total pressure and its partial pressure components as a function of the reaction extent and compaction. Al/CuO, Al/Bi2O3, Al/Sb2O3, Al/MoO3 and Al/WO3 thermites are modeled and their capability to generate pressure compared. Simulation results are also validatedthrough dedicated experiments and showgeneral agreement beyond the state of the art. Mechanisms underlying pressure generation are detailed. A two-stage process for the pressure increase in Al/CuO reaction,also observed experimentally,is shown to be driven by oxygen generation as produced byCuO and Cu2O vaporizationthrough different kinetics. Comparison with experiment stresses the issue of the understanding of the complex chemical processes taking place during vaporization and subsequent gas phase reactions and the need to determine their thermodynamicconstants.

A Performance Map for Ideal Air Breathing Pulse Detonation Engines

Abstract: The performance of an ideal, air breathing Pulse Detonation Engine is described in a manner that is useful for application studies (e.g., as a stand-alone, propulsion system, in combined cycles, or in hybrid turbomachinery cycles). It is shown that the Pulse Detonation Engine may be characterized by an averaged total pressure ratio, which is a unique function of the inlet temperature, the fraction of the inlet flow containing a reacting mixture, and the stoichiometry of the mixture. The inlet temperature and stoichiometry (equivalence ratio) may in turn be combined to form a nondimensional heat addition parameter. For each value of this parameter, the average total enthalpy ratio and total pressure ratio across the device are functions of only the reactant fill fraction. Performance over the entire operating envelope can thus be presented on a single plot of total pressure ratio versus total enthalpy ratio for families of the heat addition parameter. Total pressure ratios are derived from thrust calculations obtained from an experimentally validated, reactive Euler code capable of computing complete Pulse Detonation Engine limit cycles. Results are presented which demonstrate the utility of the described method for assessing performance of the Pulse Detonation Engine in several potential applications. Limitations and assumptions of the analysis are discussed. Details of the particular detonative cycle used for the computations are described.

Numerical and experimental study of a homogenizer impinging jet

Abstract: High-pressure homogenization is a key unit operation used to disrupt cells containing intracellular bioproducts. Modeling and optimization of this unit are restrained by a lack of information on the flow conditions within a homogenizer value. A numerical investigation of the impinging radial jet within a homogenizer value is presented. Results for a laminar and turbulent (k-epsilon turbulent model) jet are obtained using the PHOENICS finite-volume code. Experimental measurement of the stagnation region width and correlation of the cell disruption efficiency with jet stagnation pressure both indicate that the impinging jet in the homogenizer system examined is likely to be laminar under normal operating conditions. Correlation of disruption data with laminar stagnation pressure provides a better description of experimental variability than existing correlations using total pressure drop or the grouping 1/Y(2)h(2).