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EN
The paper presents the authors’ method and test rig for performing the deformation analysis of unmanned aircraft fuselages. To conduct the analysis, the DIC system was used, as well as a test rig designed and constructed by the authors, equipped with a dedicated control and load control system. The article presents a description of the research capabilities of the test rig developed for testing the deformation of unmanned aircraft fuselages. Due to the specific operating conditions of the designed fuselage,the test rig developed allows the simulation of loads corresponding to different flight conditions. In addition, it is possible to change the forces acting on the fuselage simultaneously for all servos or each of them separately. Finally, results showing the displacement of component control points for the considered fuselage versions are presented. The tests carried out using the developed test rig allowed the verification of the maximum deformations. The two versions of the composite fuselage of an aerial vehicle have been compared in the paper. The created measurement system and performed analyzes have enabled us to identify and quantitatively analyze the weaknesses of the construction. The results have enabled us to geometrically modify the constructionso the mass of the fuselage reduced by 19% and a coefficient of construction balance increased by 22%.
EN
Hydrodynamic cavitation is a phenomenon that can be used in the water treatment process. For this purpose, venturis or orifices varying in geometry are used. Studying this phenomenon under experimental conditions is challenging due to its high dynamics and difficulties in measuring and observing the phase transition of the liquid. For this reason, the CFD method was used to study the phenomenon of hydrodynamic cavitation occurring in water flow through the orifice and then analyze flow parameters for different boundary conditions. The research was performed for four different orifice geometries and two defined fluid pressure values at the inlet, based on a computational 2D model of the research object created in Ansys Fluent software. As a result of the numerical simulation, the distribution of fluid velocity and pressure and volume fraction of the gas phase were obtained. A qualitative and quantitative analysis of the phenomenon of hydrodynamic cavitation under the considered flow conditions was conducted for the defined orifice geometries. The largest cavitation zone and thus the largest volume fraction of the gas phase was obtained for the orifice diameter of 2 mm with a sharp increase in diameter. However, the geometry with a linear change in diameter provided the largest volume fraction of the gas phase per power unit.
PL
Często jedną z podstawowych obaw organizacji przed wdrożeniem systemu zarządzania energią wg normy ISO 50001:2018 jest brak odpowiednich zasobów do monitorowania energii. Firmy mają słuszne założenia, że dostęp do mierzalnych danych energetycznych sprzyja podejmowaniu decyzji, nie jest jednak prawdą, że budowa systemowego podejścia do zarządzania mediami nie może rozpocząć się od jednego licznika zainstalowanego w obiekcie.
EN
In recent years, the opposed-piston engines have become increasingly popular in the automotive and aerospace industries. Therefore, it is necessary to conduct the research on this type of drive. The paper presents the simulation research of a two-stroke opposed-piston diesel engine designed for propulsion of light aircrafts. The influence of the change of the compression ratio on the selected engine performance was investigated (indicated mean effective pressure, peak firing temperature and pressure, specific fuel consumption, power consumed by the compressor). The AVL BOOST software was used to perform the simulation tests. A zero-dimensional engine model equipped with a mechanical compressor was developed. On the basis of the created model, a series of calculations was performed for the assumed values of the compression ratio for four engine operating points: take-off power, maximum continuous power and cruising power at two different altitudes. The obtained results were subjected to a comparative analysis and the most important conclusions connected with the influence of the change in the compression ratio on the achieved performance were presented.
EN
The aerodynamics of powerboats used in inshore powerboat racing has a significant impact on their performance. The aerodynamic drag forces generated on individual elements of this type of boats were tested. The solid model of the boat developed in the CAD software was used for the calculations. The computational grid was generated, as well as the boundary conditions and the turbulence model, were determined. On the basis of such assumptions, the numerical calculations were carried out using the CFD method. The results from the numerical simulations consist of a description of the velocity and pressure distribution around the tested object and identification of the drag force on the components of the powerboat with a description of the relationship between them. Additionally, the variation of the drag force as a function of speed in the range from 0 to 60 m/s was presented. The tests were performed for 5 values of the angle of attack of the boat to the surface of water in the range from 0° to 12°. The scope of the research allowed for the development of a drag force map depending on the defined parameters. The test results can be used to optimize the shape of the boat structure in order to reduce the aerodynamic drag generated on its individual elements.
6
Content available Turbocharging the aircraft two-stroke diesel engine
EN
The power and efficiency of a two-stroke engine strongly depends on the efficiency of the scavenging process which consists in removing the rest of the exhaust gases from the cylinder and filling it with a fresh charge. The quality of the charge exchange process is significantly influenced by the construction of the intake system. The paper presents a zero-dimensional model of the aircraft two-stroke opposed-piston diesel engine with two variants of the intake system: with a mechanical compressor and a turbocharger connected in series with a mechanical compressor. Simulation studies of the developed cases were carried out in the AVL BOOST software. For the defined engine operating points, its performance was compared for different designs of the intake system. It was confirmed that the use of a turbocharger with a mechanical compressor extends the range of operating at high altitudes.
EN
This paper presents the results of experimental studies of the opposed-piston diesel engine. This engine was designed during one of the stages of the research on a new-type drive unit for gyrocopter applications. In order to conduct research, a special test stand as well as control and measurement systems were developed. As part of the work on the engine, the fuel injection system, engine temperature control system and measurement systems were designed. In addition, a computer program has been developed for the fuel injection system control (injectors, valves fuel pressure regulators). The paper presents the results of the preliminary tests for a single value of engine speed (1500 rpm) and three values of load defined by torque. The measured value of the indicated pressure made it possible to calculate the maximum pressure. The results obtained from the bench tests were analyzed.
EN
The paper presents an analysis of the possibility of using a common rail pump to supply an aircraft compression-ignition engine. It is an engine with a two-stroke cycle, three cylinders, opposing pistons and 100 kW power. Its each combustion chamber is supply by one or two injectors controlled by electromagnetic valves. In order to assess the possibility of using a common rail pump, four high-pressure pumps were tested on a bench. They are piston pumps differing in the number and geometry of their pumping sections. The analysis included the pumping output, the torque on the pump drive shaft and the power needed to drive the pump. The weight and overall dimensions of the pump were also considered, including the arrangement of the pumping sections and the way the drive is transmitted. The research allowed to optimize the engine power supply system depending on fuel demand and the way the pump is mounted on the engine.
EN
The work presents a three-dimensional modeling of air flow around the research object. The purpose of this work was to perform numerical calculations to identify the magnitude of the aerodynamic drag force generated on individual elements of a high energy efficiency vehicle body. This vehicle, specially designed for the Shell Eco-marathon competition, needs to show the lowest possible fuel consumption while maintaining the prescribed speed. Minimizing the drag force at an early designing stage plays an important role here. The calculations were performed using the ANSYS Fluent calculation solver. The result of the conducted research is a description of the velocity and pressure distributions around the tested vehicle as well as an identification of the drag force on the external surfaces of the components and a description of the relationship between them. The work also discusses the dependence of the drag force as a function of speed in the range from 0 to 12 m/s. The influence of the ground on the drag force in the case when the object was immobilized in relation to the walls at the flowing medium, as in a wind tunnel, was investigated. On the basis of the calculations performed, no impact of the ground on the generated drag force magnitude was found.
EN
The performance of the engine strongly depends on the parameters of the combustion process. In compression ignition engines, the fuel injection timing has a significant influence on this process. The moment of its occurrence and its duration should be chosen so that the maximum pressure value occurs several degrees after TDC. In order to analyze the effect of the fuel injection timing on the performance of the tested two-stroke opposed-piston diesel engine, a zero-dimensional model was developed in the AVL BOOST program. Next, a series of simulations were performed based on the defined calculation points for maximum continuous power, which resulted in power, specific fuel consumption and mean in-cylinder pressure. Finally, the engine map was made as a function of the start of combustion angle.
11
EN
The paper presents the numerical analysis of the drag force generated on the body of a sports car, based on the CFD method in the Ansys Fluent program. The three-dimensional model of the vehicle was taken from an open CAD database. Based on this, a computational grid was developed, boundary conditions and a turbulence model were defined. As a result of the calculations, the pressure distribution on the individual body parts and the velocity distribution in selected cross sections were obtained. In the next part of the research, the simulation results are used to optimize the shape of the bodywork of different passenger vehicles in order to reduce the generated drag force.
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