Max Mason, Miroslaw L. Wyszyński, Owen Jordan and David Gibson
This paper outlines the methods and results of computations completed using the ANSYS Fluent code modelling the fuel injection and combustion within the K6 engine, a new form of rotary engine in which the fuel is injected in an arc across the top of the cylinder. The model uses the DPM Model in conjunction with a dynamic mesh and non-premixed combustion models to treat the injection as liquid diesel evaporating to C12H23. The outcomes of this model are presented in images displaying the distribution of temperature, and fuel and CO2 concentrations. The limitations pertaining to the maximum injection angles are also studied. The simulation is found to be effective and the results suggestive of successful, clean and complete combustion while presenting some matters, which require further investigation. The article presents temperature within the combustion chamber at various crank angle degrees, ) velocity of fluid within the combustion chamber, effects of impingement with injector offset on temperature and fuel concentration, fuel concentration demonstrating impingement, in cylinder temperature curve
The article presents selected problems in the synthesis of the database of expert diagnostic system of gas turbine blades in the field of non-destructive testing. The source of data is optical methods and computed tomography methods. Optical tests can be carried out on the blades of the turbine built in the engine and after their disassembly. Optical tests provide diagnostic information in the form of an image of the blade surface. This makes it possible to identify damage based on changes in the attributes of the image of the blade surface. Computer tomography methods are applied on disassembled blades. Assessment of the technical condition of the blade is made on the basis of individual two-dimensional X-ray scans or on the basis of a three-dimensional image of the blade generated by the computer software from the set of X-ray scans taken during the full angle rotation. The computed tomography data set includes a small number of points on the timeline of operation; hence, the correlation of results with optical methods is difficult. Integration of diagnostic data from two or more sources into one expert system requires standardization of data. One possible approach is the use of multi-valued encoding of 2D and 3D image attributes. In this way a multi-valued diagnostic model of the blade is obtained, which can be processed by information theory methods to optimize the set of attributes.
Wojciech Gliwa, Andrzej Żyluk, Norbert Grzesik and Konrad Kuźma
The article discusses the automatic control system of the Diamond DA42 aircraft anti-icing system. In the analysis of the issue of icing, four parameters were taken into account: air temperature, cloud humidity, temperature of the aircraft and precipitation. On the basis of the initial parameters, the authors determined the icing intensity, which is likely to occur on the aircraft skin. By automating the activities related to the activation of the de-icing system, it is possible to significantly relieve the pilot and increase the safety of air operations, particularly in conditions, which are conducive to the formation of icing. The authors performed a thirty-minute electronic simulation of the flight in real atmospheric conditions. The article discusses the obtained results of the simulation. Designed system uses fuzzy logic. The system inputs and output were determined and fuzzy expert inference system was developed in MATLAB software and Fuzzy Logic Toolbox. The proper system work was verified with use of MATLAB/Simulink software. Use of that kind of systems can significantly relieve the pilot and increase the safety of air operations, particularly in conditions, which are conducive to the formation of icing.
Low speeds of heavy mobile machines combined with large inertia result in the excitation of low frequency vibrations. Dissipation of vibration energy in the case of unsprung machines is performed only through tires, which slightly reduces the intensity of vibrations. Effective reduction of vibrations of mobile machines is possible only with active or semi-active methods. In unsprung mobile machines, on the way of propagation of vibrations between the source of vibrations and the protected object (machine operator), are vibroisolation systems located. These are most often controlled seat suspensions. In the case of the active suspensions, it is necessary to provide external energy, e.g. in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator and its experimental identification. In particular, it was verifying the effectiveness of the adopted solution made the identification the friction model and thermodynamic phenomena in the controlled pneumatic cylinder. The aim of this work is parametric optimization of the suspension system and searching for the optimal control strategy. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using MATLAB-Simulink Real-Time software.
Aircraft are exposed to lightning strikes. Lightning strike protection (LSP) devices involve additional weight of the aircraft. Therefore, multifunctional materials that allows the conductivity of electrical current and, simultaneously, holds the mechanical properties required to withstand the typical conditions for an aerospace material are widely researched. A typical resin used in aviation is an insulator, so main research is done to reduce its resistance. On the other hand, the type of reinforcement can have a large influence on the electrical conductivity in the plane of reinforcement. The aim of the article is to evaluate the effect of the type and the basis weight of reinforcement on the electrical conductivity. For this purpose, with the use of a hydraulic press, different four-layer composites based on epoxy resin were produced. Each differing is in combination of carbon, glass layers and their basis weight (from 48 kg/m2 to 245 kg/m2). The measuring proceedings were carried by an RMS multi meter and, more accurate, by an LCR meter with 4 selectable test frequencies. The measurements were made both along the strand fibres and at a 45-degree angle. The results made it possible to determine which reinforcement of aircraft composites should be selected at the aircraft design level to provide increased electrical conductivity along the reinforcement fibres and thus influence one of the factors affecting the protection of the aircraft against the effects of lightning.
The article analyses activities within the world, EU and Poland in aspect electromobility and hydrogenization now and in the future. Will be presented estimates cars park of global hybrid (HEV), hybrid plug-in (PHEV) and fully electric (BEV). Changes in production volumes and number of registered types of vehicles as abovementioned are presented in a breakdown into world.
The overall number of HEVs produced thus far is estimated at approx. 12.5 million and over 1.3 million in Europe. There are roughly 38 thousand HEVs registered in Poland. There were about 800.000 hybrid plug-in vehicles registered in the world in 2016. Of 3.2 million electric plug-in vehicles and BEVs used in the world in 2017 more than 1.2 million were used in China, approx. 750 thousand in the USA, 850 thousand in Europe, including c.a. 650 thousand in the EU countries.
Yet, electric plug-in vehicles (BEVs and PHEVs) globally accounted for just 0.3% of the worldwide fleet of passenger cars in 2017. The article also addresses the development of the electric vehicles market and the annual new vehicle registrations.
The existing situation in the field of hydrogenization motor transport in the world, in the EU and in Poland will also be analysed. This will be analysed in terms of the number of hydrogen vehicles and hydrogen refuelling stations.
Paweł Stężycki, Mirosław Kowalski and Antoni Jankowski
The article presents a method of piston temperature measurement on a running engine using electromagnetic induction for transferring measurement results from a moving measuring system placed in a piston to a stationary system attached to the engine crankcase and to measuring system located outside the engine. Selected test results that were carried out on a single-cylinder Diesel engine are presented. A system consisting of a thermistor and a secondary coil was mounted in the piston. The primary coil was mounted in the crankcase under the cylinder liner of the engine. Engine tests were aimed at determining the influence of the piston ring insert on the temperature distribution in the piston. Temperature measurements in the piston without the ring insert were carried out for comparison. In both cases, the pistons had the same geometrical dimensions. The tests were carried out in conditions of external characteristics (the maximum load as a function of engine speed) and load characteristics (load changes at constant engine speed). The test results in the form of the temperature difference between the temperature of piston top and the temperature under the top compression ring indicate that the ring insert is a barrier to the heat flow from the piston to the engine cooling system. In addition, the results of the piston temperature measurements during the step change of the engine speed and its load to the nominal value are presented.
Maria Skrętowicz, Radosław Włostowski and Cezary Kozłowski
The new passenger car, BMW 225 XE was tested. The results of measurements of concentration of VOCs carried out inside the car cabin depending on the temperature were presented. The investigation was carried out in a special climatic chamber isolated from external factors such as outside air pollutants and weather conditions. The following temperature values have been set: 17ºC, 20ºC, 35ºC and 50ºC. The samples were located inside and outside of the vehicle’s cabin. As expected, the concentrations of each compound increased with increasing temperature (volatility of VOCs increases with the temperature). Values of concentrations obtained in the measurements have been compared with the values of highest acceptable concentration specified in polish law. The article describes the investigation, which was provided in a special climatic chamber. The chamber was isolated from external weather conditions and pollutants. Before each sampling interior of car cabin was ventilated to remove all pollutants from inside. Concentrations of BTX measured in different temperatures were converted to temperature of 20ºC.
Research in the field of fracture mechanics and determination of material characteristics are used for practical purposes, such as the assessment of static and dynamic strength of structural components, analysis of their fatigue life or extending the life span of their operation. A structural component, considered to be safe from fatigue cracking point of view, was investigated and results were presented in this article. In particular, an analysis was made to determine the stress intensity factor for the cracked wing flap construction, based on static and fatigue tests, using the Irwin-Kies theory. The flap with a service crack was subjected to fatigue tests with a load similar to the one registered during flight measurements. The flap without a service crack was subjected to static tests, after cutting the cracks of specified lengths and shapes (similar to the service crack) in the skin of the flap. The article presents changing the length of the flap crack in subsequent load cycles, change in the maximum values of force and the crack opening displacement in subsequent load cycles, dependence of P-COD in the first and second stage of fatigue testing of the wing flap, dependence of the wing flap compliance on the length of the crack and experimentally determined dependence for wing flap. The occurrence of a flap crack up to approximately 230 mm does not cause a significant growth of the stress intensity factor.
Grzegorz Kowaleczko, Andrzej Żyluk, Mariusz Pietraszek and Mirosław Wijaszka
The article presents the results of numerical simulation of a laser-guided bomb, which is dropped in calm weather conditions. The prototype of such a bomb was developed at the Air Force Institute of Technology. It was a result of the modification process of the classical training bomb. The modification consisted of building on the bomb's board a detection system to track targets that are designated by laser and a control system to adjust bomb’s glide path to precisely strike the target. In the simulation research, geometric and mass characteristics of the classical training bomb were used. Aerodynamic characteristics of the bomb have been determined using commercial software PRODAS. Using the mathematical model of the bomb spatial motion and model of the laser detection system series of simulations were performed. The main goal was to determine the effectiveness of the adopted construction solution. Therefore, simulations were performed for various initial positions of the bomb and fixed position of the target. It allowed finding the set of control laws coefficients giving the most accuracy of the bomb. The influence of structural modifications of the detection system on the possibility of effective detection and location of the target was also investigated. In the article, exemplary results of numerical calculations performed with the author's software are also shown.