Senthil Ramalingam, Silambarasan Rajendran and Pranesh Ganesan
The objective of the present work is to find out the viable substitute fuel for diesel and control of pollutants from compression ignition engines. Therefore, in this present investigation an attempt has been made to study the effect of 20% proportion of five different biodiesel diesel blend in diesel engine. The 20% proportion of biodiesel such as Jatropha, Pongamia, Mahua, Annona and Nerium and 80% of diesel and it is denoted as J20, P20, M20, A20 and N20 are used in the present investigation. The experimental results showed that the brake thermal efficiency of the different biodiesel blend is slightly lower when compared to neat diesel fuel. However, N20 blend, have shown improvement in performance and reduction in exhaust emissions than that of other biodiesel diesel blends. From, the experimental work, it is found that biodiesel can be used up to 20% and 80% of diesel engine without any major modification.
The conducted experiments were conducted on a four cylinder four stroke DI and turbo charged diesel engine using biodiesel blends of waste oil, rapeseed oil, and corn oil with normal diesel. The peak cylinder pressure of the engine running with bio diesel was slightly higher than that of diesel. The experiments were conducted on a four cylinder four stroke diesel engine using bio diesel made from corn oil.
Wieńczysław Stalewski, Wiesław Zalewski, Katarzyna Surmacz, Maximilian Pulfer and Frieder Hirsch
In trimmed flight of a helicopter, all the forces and moments, aerodynamic, inertial, and gravitational, are in balance. Keeping the helicopter in trimmed state, needs a precise adjustment of flight controls. The methodology of simulation of a fully trimmed flight of rotorcraft has been developed and applied to simulate hover of a helicopter.
The presented approach is based on a solution of Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. In contrast to typical solutions of such problem, in the newly developed methodology, the flight controls corresponding to the trimmed-flight conditions are also determined based on the solution of URANS equations.
The methodology is based on coupling of several computational models of Computational Fluid Dynamics and Flight Dynamic. The URANS equations are solved in a three-dimensional region surrounding the flying helicopter, using the ANSYS FLUENT code. The approach is truly three-dimensional, with truly modelled geometry and kinematics of main and tail rotor blades. This applies to modelling of blade flapping and lead-lag motion, too.
The trimming procedure uses six independent parameters (i.e. collective and cyclic pitch of main rotor blades, collective pitch of tail rotor blades, pitch, and bank angles of a helicopter) that should be adjusted so as to balance all forces and moments acting on the helicopter.
The detailed description of the developed methodology as well as the results of simulation of trimmed hover of the helicopter was presented.
In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.
One of the most important parameters affecting traction properties as well as driving safety, especially with regard to vehicles with special purpose, is the distribution of wheel and axle loads on the ground. This issue should be taken into account during the process of creating new vehicles as well as during the modernization process. In the first case, it is quite simple because the mass distribution is shaped already in the design phase. In the second case, the problem is more complex, because with modernization solutions we enter an already existing structure. Modernization basically assumes improving the performance and capabilities of the vehicle with possibly small changes in its base structure. Thus, it imposes important boundary conditions. The article presents the methodology of measurement and selected results of measurements of mass distribution as well as wheel and axle loads of selected motor vehicles during their advanced modernization (STAR 266 cars to the version STAR 266M2 and Honker 2000 to the version Honker M-AX). Modernizations carried out by Autobox Innovations Ltd. Lim. Par are mainly focused on increasing the traction of vehicles, traffic safety, and driving comfort. Measurements were made at the above-mentioned company.
In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.
A. Renuka Prasad, Rakesh Bhandari and Donepudi Jagadish
Homogeneous Charged Compression Ignition technology is most favourable or suitable for Internal Combustion engines for reducing the exhaust emissions and enhances the Thermal efficiency, improve the fuel consumption, and increase the rate of combustion. This article represents the various charging methods on HCCI technology engine; it improves the engine performance and determines the emission characteristics of HCCI technology engine. The homogeneous mixture prepared with different methods. In–cylinder internal homogeneous mixture preparation method applied in this present work. It reduces the exhaust emissions released from the combustion chamber. However, oxides of nitrogen and soot emissions are significantly reduce, because combustion starts at lower temperatures and various points in combustion chamber.
The HCCI technology generates small amount of exhaust emissions and it improves the performance of the engine. In addition, performance and released emissions depends on the quality and quantity of homogeneous mixture.
This article presents results of experimental investigations of the lap blind riveted joint. The main goal of the work is determination of destructive load of the blind riveted joints. The blind rivets were originally used in the aircraft structures where access to both sides of the riveted structure is impossible. Blind rivets are now commonly used in many branches of industry because of their low cost. Moreover, the riveting process is uncomplicated. There are many publications about analysis of strength of solid rivets in the research literature. However, the strength analysis of the blind rivets was rarely undertaken. There is the research gap in the analysis of both the strength and the load capacity of blind riveted joints. The influence of selected geometrical parameters of the joint on the stress distribution and the destructive force was not widely described in literature. The first part of the work presents a review of standards and publications related to stress and strength analysis of blind riveted joints. The next part of the study describes experimental investigations of joints. The examined specimens were made out of AW 2017 aluminum alloy, cut from 1 [mm] thick sheet. Investigated blind rivets were made out of aluminum alloy. The lap joint with one rivet and the single row five-rivet joint were investigated. Moreover, the different size of hole chamfer were considered. The experimental tests were performed with the use of Zwick-Roell tension machine. The main results of experimental investigations are ultimate shear load diagrams. The influence of both the hole chamfer and the number of rivets on destructive force and shear diagrams of blind riveted joints were in detail analysed. After shear tests, the fractured rivets were magnified in order to explain the failure phenomenon of blind rivets. In the future research works the obtained results will be used in strength analysis of the blind riveted joints using the finite element method.
Adam Bilar, Paweł Boguszewicz and Witold Perkowski
During preliminary tests of locomotive windshield resistance to gravelling, according to the applicable standard PN-EN 15152:2007, carried out in the Institute of Aviation, the problem of the projectile overturning after leaving the cannon barrel was detected. Three tests recorded with a high-speed camera are presented in this article. This problem was found to be due to the incorrect projectile geometry.
In order to stabilise the trajectory of the projectile, four types of projectiles were made using military experience. All of them meet relevant test conditions from the point of view of the test piece (locomotive windshield). The best projectile modification was obtained in the tests with an average deviation of the expected impact angle of 11° compared to 75° for a projectile made exactly according to the guidelines of the standard. Each of 22 modified projectiles hit the test piece with the tip, while out of the 12 original projectiles only 4 hit the test piece with the tip. The impact test results confirm that it is possible to perform a gravelling test according to the standard concept, but it seems necessary to clarify the standard requirements and to modify the projectile shape.
The article contains a proposal for the projectile modification and highlights inaccuracies in the standard concerning the gravelling test.
Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis.
In this article, authors describe possible landing gears health monitoring methods based on authors ’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.
One of the most important subsystems of the vehicles and machines operating currently in industry and transportation are the rotating subsystems. During the subsystems operation, due to the forcing factors influence, the technical state of them is changing and the failure can occur. In order to avoid such a situation the technical state should be identified online. To do this the analysis of the subsystems vibrations is performed. The identified technical state should be considered in a context of the ability and different inability states. Therefore, the first step of the diagnostic procedure is the ability and different inability states identification. In the article, it is proposed to accomplish this goal by the vibrations analysis in time domain. The described research started with the vibration signals acquisition using the experimental stand. In this way, the vibration signals for ability and different inability states were obtained. Afterwards, the signals were divided into learning and testing data sets. For each signal from learning data set, several characteristics were calculated, and they selected the most significant among them. Using the selected characteristics, the signals from the testing data set were analysed. Thanks to it, the testing vibrations signals were counted among the signals collected on the rotating subsystem operating in ability or selected inability state. The result of the performed studies and the accuracy of the technical state of the tested system identification can be found at the end of the article.