L∞ SOLUTIONS FOR A MODEL OF NONISOTHERMAL POLYTROPIC GAS FLOW∗ HERMANO FRID† , HELGE HOLDEN‡ , AND KENNETH H. KARLSEN‡ Abstract. We establish the global existence of L∞ solutions for a model of polytropic gas flow with varying temperature governed by a Fourier equation in the Lagrangian coordinates. The result is obtained by showing the convergence of a class of finite difference schemes, which...

This paper provides a novel health monitoring classification algorithm to estimate the level of valve leakage in reciprocating compressors. It is expected that will change shape pressure-volume diagram. method constructs feature space using polytropic exponent during expansion and compression phases as well discharge suction loss power. These features are extracted by measuring in-cylinder pres...

Abstract Experimental regulating parameters of the non-stationary expansion air inside a bladder-type hydraulic accumulator, working with simple short pipeline, are presented in paper. The technique continuous online monitoring changes time volume and absolute pressure accumulator during discharge process has been improved. Three series experimental studies transient gas processes at different ...

The polytropic (adiabatic) index for pure hydrogen plasma is analytically calculated as function of reciprocal temperature and degree ionization. Additionally, the graphically represented a density. It concluded that partially ionized cannot be exactly polytropic. deviations from mono-atomic value 5/3 are measurable. analytical result test example how this approach can extended arbitrary gas co...

A solution to an equilibrium of irrotational binary polytropic stars in Newtonian gravity is expanded in a power of epsilon = a(0)/R, where R and a(0) are the separation of the binary system and the radius of each star for R = infinity. For the polytropic index n = 1, the solutions are given almost analytically up to order epsilon(6). We have found that in general an equilibrium solution should...

We find type I critical collapses of compact objects modeled by a polytropic equation of state (EOS) with a polytropic index Gamma=2 without the ultrarelativistic assumption. The object is formed in head-on collisions of neutron stars. Further, we show that the critical collapse can occur due to a change of the EOS, without fine-tuning of initial data. This opens the possibility that a neutron-...

We analytically study how the behaviour of accretion flows changes when the flow model is varied. We study the transonic properties of the conical flow, a flow of constant height and a flow in vertical equilibrium and show that all these models are basically identical provided the polytropic constant is suitably changed from one model to another. We show that this behaviour is extendible even w...

The compression process in a piston cylinder device in a Compressed Air Energy Storage (CAES) system is studied computationally. Twelve different cases featuring four different compression space length-to-radius aspect ratios and three different Reynolds numbers are studied computationally using the commercial CFD code ANSYS FLUENT. The solutions show that for compression with a constant veloci...