Abstract: In this paper, the design of a box type solar cookeris presented first. The main components of this solar cooker are inner and outer reflectors, a double glazing, an absorber plate and a cooking box. Secondly, in order to predict the evolution of the temperatures of the main components of the solar cooker,a mathematical model was developed and implemented in a MATLAB program using finite differences method. To validate the accuracy of the calculations further numerical simulations were realized using Solidworks simulation tool. After that, simulations were developed on the solar cooker before enhancement and after enhancement with four outer reflectors. The obtained results show that the enhancement has a great influence on the maximum temperature of each component and on the availability of the solar cooker.

Key words: Design, box type solar cooker, mathematical model, numerical simulations, reflectors.

Abstract: This work presents the design of a double pass solar air heater fixed on the wall by a four legs design pivoting system. In the case of supplying a building with hot air, for heating purposes, or for industrial applications such as drying or preheating, this pivoting mechanism consists of two supports with two legs linked to the collector itself and the fixing is ensured by two clevises. To make a static simulation of the pivoting mechanism, we use the CAD software Solid Works. According to the obtained results, we can approve that our support can bear the load of the solar collector and resist to weather conditions.

Key words: Double pass solar air heater, four legs design pivoting system, static simulation, Solidworks.

Abstract: In this paper, we simulated numerically the non-premixed combustion provided by two coaxial methane-propane/air jets in a cylindrical combustion chamber. Using CFD Fluent commercial calculation software. In order to find the aero-thermo-chemical characteristics in the burner: temperature, axial velocity and mass fraction of carbon monoxide CO. To study this kind of phenomenon, we used a special treatment of the mathematical model and we chose two models of computation large eddy simulation (LES) and the probability density function (PDF). The objective of this work is to reduce the emission of carbon monoxide CO, and what is considered a gas toxic to the environment. The results obtained give the fuel of methane reduces the carbon monoxide in the products of combustion.

Key words: Models LES and PDF; Combustion Chamber; Methane; Propane; Numerical Simulation CFD.

Abstract: This paper will present an algebraic model closure of the turbulent fluxes as the sum of two contributions acting in opposite directions, one induced by turbulent motions and the other by thermal expansion. The turbulent transport is analyzed that for a sufficiently high turbulence level, the flame is unable to impose its own dynamics to the flow field, and the turbulent transport is of the gradient transport type for the reacting scalar c and when the turbulence level remains low, the thermal expansion due to heat release dominates the process of turbulent scalar transport and the turbulent transport is of a counter gradient turbulent transport. The combustion will occur in a variable equivalence ratio and as partially premixed combustion is highlighted as one of the most relevant and important modeling challenges in the field of turbulent premixed combustion, we will use the LW-P model of combustion for this situation. The resulting model is combined with the second order model of turbulence Rij, ? has evidenced the pressure drop across the flame due to counter gradient diffusion turbulent fluxes which has well predicted the jump of the axial velocity across the flame brush. A numerical simulation which corresponds to the experimental conditions of the experiment of Escudié and Haddar is presented in order to validate the model. The comparison of the results with the measurements were showing remarkable consistency and indicates that the model is a valid approach for predicting partially turbulent premixed flames stabilized in a stagnation flow.

Key words: Partially premixed combustion, Stagnating flow, Libby-Williams-Poitiers model, Numerical combustion simulation, Counter gradient diffusion turbulent fluxes

Abstract: In this work a comparative study was conducted on the longitudinal dynamics and flight control for four types of aircraft (General aircraft, business aircraft, fighter aircraft and commercial aircraft). We have established the fundamental equations of motion for a rigid aircraft using the laws of mechanical and aerodynamic models. Therefore, an analysis of stability and control is made for every case to determine different dynamic characteristics (longitudinal modes of flight, frequencies and damping coefficients). Also, two kinds of automatic control systems have been designed for four types of aircraft. At the end, some applications are carried on real aircraft models (Cessna 172, M24Learjet, F4C and Boeing 747) and simulation results are presented for each type of aircraft.

Key words: Aircraft, Flight dynamic, Flight control, Stability, Simulation, Modes, Frequency, Damping.