جستجوی مقالات مرتبط با کلیدواژه "kerosene" در نشریات گروه "مکانیک"

In the present study, the spraying behavior of diesel and kerosene fuel in a cylindrical fixed volume combustion chamber for a injector orifice has been investigated. In order to investigate the effect of injector geometry on fuel spray characteristics and atomization quality, different geometries have been used. For this purpose, the microscopic and macroscopic properties of the diesel and kerosene fuel spray for different geometries of orifice compression ignition injectors are modeled and investigated using AVL-Fire. Firstly, the liquid fuel flow inside the injector with cylindrical and converged conical nozzle holes have been modeled and then in the following diesel and kerosene fuels have been used in the grooved nozzle hole. Numerical results show that in this case, the kerosene spray has smaller penetration length and bigger cone angle than diesel fuel. Controlling the properties of the fuel spray is important to increase the combustion efficiency of the engine and also to reduce their pollution, and can be done by changing the geometry of the fuel injector nozzle.

Convergent-end and Open-end injectors are widely used in internal combustion engines. These types of pressurized swirl injectors include: tangential inputs, rotation chamber, converging section and output orifice. In this paper, simulation and comparison of fluid flow inside Open-end and Convergent-end injectors for spraying kerosene fuel under the same operating conditions has been performed using the fluid volume (VOF) method. The results of time-dependent (unsteady) simulations showed that the exit time of kerosene from the Open-end injector is 1.8 milliseconds and in the Convergent-end injector is 4 milliseconds. The results of time-independent (steady) simulations at different injection pressures showed that the Open-end injector is stable at 0.05 MPa injection pressure, while the convergent-end injector is stable at 0.3 MPa injection pressure. However, the exit rate of kerosene in the Open-end injector is far less than that of the convergence-end injector, which reduces the aerodynamic force applied to the fuel inlet layer of the injector and reduces the fuel atomization in the Open-end injector compared to the convergent-end injector.

The purpose of the present paper is to investigate the influence of different chemical mechanisms on non-premixed combustion of Kerosene liquid fuel in a gas turbine model combustor. Numerical simulations of two-phase reacting flow in this combustor is performed by Realizable k-ε turbulence model, Steady Laminar flamelet combustion model, and Discrete Ordinates radiation model in a structured finite volume mesh. An Eulerian-Lagrangian approach is applied to model droplet spray of liquid fuel. The results in the present paper are obtained using three different chemical reaction mechanisms for Kerosene and the boundary conditions in the three cases are based on the experimental conditions. Validation of the results are performed by comparing the velocity and temperature distributions with the avalible experimental data. Accordingly, the results obtained by the first chemical reaction mechanism, which consists of 17 species and 26 reactions, are more accurate and closer to the experimental data. Comparisons of the mean velocity and temperature distributions with available experimental data are one of the outputs of the present paper. Also, the quantity of scalar dissipation rate, mixture fraction, mass fraction and the rate of formation of carbon dioxide, water vapor, Kerosene and nitric oxide are compared for the three different chemical reaction mechanisms. The results show that because of differences in the decomposition rate of C12H23 and consumption rate of O2, average mixture fraction in the chemical mechanisms are different. In addition, the scalar dissipation rate of the flame is affected by the turbulent flow in the three mechanisms. Further, the concentration of produced NO and CO2 in the flame region using the three mechanisms are different due to the flame temperature differences.

Gas aerothermodynamics is the thermodynamics of a gas in high velocity associated with heat transfer. One of the devices which takes advantage of this field is a rocket system. High velocity flow filed with intensely varying pressure and temperature along the nozzle axis leads to reduction of residence time. This means the balance between chemical and flow time scales is changing in the flow stream. In this study, reacting flow composition variations in combustion chamber and nozzle of a liquid rocket engine is numerically investigated for hydrogen and kerosene fuels regarding combustion efficiency and performance of the engine. Numerical modeling has been conducted with the aid of commercial code FLUENT. k −e turbulence and EDC combustion models have been used to consider turbulence effects on the flow field. 9-step and 14-step skeletal mechanisms have been utilized to represent chemical oxidation of kerosene and hydrogen, respectively. Results show a reasonable accuracy in comparison with experimental measurements. As a result of this study, it can be concluded that in combustion chamber and convergent nozzle, the frozen and finite rate modeling have almost same results in all equivalence ratios. However, in divergent section of the nozzle some reactions proceed in finite rate regarding to fuel type. Finally, it can be noted that maximum Damkohler number occurs in the same axial position for both kerosene and hydrogen fuels.