Analytical solutions for the temperature field in a 2D incompressible inviscid flow through a channel with walls of solid fuel

A gas (oxidizer) flows between two parallel walls of solid fuel. A combustion is initiated: the solid fuel is vaporized and a diffusive flame occurs. The hot combustion products are submitted both to thermal diffusion and convection. Analytical solutions can be obtained both for the velocity and temperature distributions by considering an equivalent mean temperature where the density and the thermal conductivity are evaluated. The main effects of heat transfer are due to heat convection at the flame. Because the detailed mechanism of the diffusion flame is not introduced the reference chemical reaction is the combustion of premixed fuel with oxidizer in excess. In exchange the analytical solution is used to define an ideal quasi-uniform combustion that could be realized by an n adequate control. The given analytical closed solutions prove themselves flexible enough to adjust the main data of some existing experiments and to suggest new approaches to the problem

More direct methods to evaluate general relativity effects. The influence of the age of the Universe

More direct methods are given to evaluate the general relativity effects by simplifying the solving the solution of the extremum of variational problem to one variable only. The influence of the age of the Universe is mainly related to the variation of the coefficient of gravity the age of the Universe

An Interpretation of the “Black Energy” in Universe by Using a Hydro-Dynamical Analogy with Newton Gravity

There are arguments proving that what we see now as “normal energy” (including the equivalent mass-energy) represents only 5% of the total energy of the Universe [1]. The rest is invisible meaning that no widely accepted experimental proof exits to put it in evidence. In addition, there is no accepted theory to explain the nature of this so-called “black energy”. This paper deals with an interpretation of the “black energy” also giving the possibility to follow its evolution in time by using an author hydro-dynamical model of the Newton gravity and a model of the early Universe; a connection between a part of this energy and the “black holes” is as well proposed

A detailed laminar flow field within the normal shock wave considering variable specific heats, viscosity and Prandtl numbers

The gas flow field within an 1D normal shock wave at variable specific heats, viscosity and Prandtl numbers with temperature is considered. At Pr = 0.75 and constant specific heats and viscosity, the already known analytical solution in a somehow different form is found. At some distance from the wave, the flow is isoenergetical (constant total enthalpy). In order to see if the isoenergetical character of flow within the shock wave is maintained, a method to correct the solution for variable Prandtl number is developed. The obtained solution is close to an analytical one and proves that the deviation from the constant enthalpy hypothesis is less than 0.5%. An interesting thing pointed out is the coexistence of the supersonic and subsonic regimes within the shock wave. Examples of application for air at two Mach numbers are given

An Analytic Potential Solution for Incompressible 2D Channel Inviscid Flow with Wall Injection

The present paper introduces an analytical potential solution for the incompressible flow ina 2D channel with normal wall injection. This solution is capable to support reasonable injection flowrates as compared to the general flow rate in the channel. A strategy to find solutions for longerchannels in case of increasing injection velocity with the distance from the entrance, using a smallnumber of the solution terms is pointed out. Examples of calculation are given

Special Topics on Map Meshing in Turbomachinery

The purpose of this paper is to present various kinds of options as regards the computational mesh generation that is required by the analysis of flow in axial turbomachinery (compressors and turbines). Specific cases of interest as both the rotating and fixed blade row profiles and axial stage are focused. There were highlighted the very best options of mesh generation that lead to a good level of computational accuracy. Therefore, one may consider this paper as a successful attempt to be a useful guide of the first steps in computational analysis of flow in turbomachinery

Possible Simple Structures of the Universe to Include General Relativity Effects

The general relativity describes the universe properties, the gravity playing a fundamental role. One uses a metric tensor in a Riemann space, g , which should be in agreement with a mass (or energy) tensor in order to satisfy the Einstein equation of the general relativity [1]. This equation contains the Ricci curvature as well. In general, applications are done considering that a chosen metric is valid without region limits. In fact, the density of the energy whose distribution is however unknown is variable in universe; therefore, the metrics need to be adapted to different regions. For this reason one suggests to start with a simple, average mass-energy distribution that could represent in a first step the actual universe. This suggestion is in agreement with the symmetrical distribution of equal spheres existing in a model of the early universe given by one of the authors. Two kinds of distribution are given. The possibility of black holes formation is studied and a criterion is given

A Possible Universe in Pulsation by Using a Hydro-Dynamical Model for Gravity

By using a hydro-dynamical model for gravity previously given by the author, a pulsating universe is possible to describe. This is possible because two hydro-dynamical sources are in attraction both when they are emitting and absorbing fluid. In our model, bodies (matter and energy) are interacting via an incompressible fluid made of gravitons (photon-like particles having a wave length of the order of magnitude of the radius of universe). One considers the universe uniform at large scale, the effects of general relativity type being local and negligible at global scale. An “elastic sphere” model for the universe is suggested to describe the possible inversion. The expansion of the universe stops when the “elastic energy” overcomes the kinetic one; this takes place near the point of maximal emission speed of the fluid of gravitons. The differential equation for the universe in expansion is adapted to contraction. Analytical solutions are given