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Design of aircraft power unit
Poledno, Martin ; Maňas, Pavel (referee) ; Nevrlý, Josef (advisor)
This diploma thesis deals with basic design and calculation of an aircraft power unit (APU). For desired shaft power the thermal cycle is calculated. Basic dimensions of compressor, turbine and exhaust system are calculated as well as thermodynamic parameters of air and hot gases along the motor. Corresponding compressor map, turbine map and characteristics of the exhaust system are designed. Based on these characteristics, an effective shaft power is being calculated in various off-design conditions. Dependency of the shaft power vs. altitude is also presented. All the calculations are made in MATLAB. Finally, simplified motor cross-section is created.
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Energy recovery at braking and start of vehicles
Vodák, Martin ; Fichta, Martin (referee) ; Nevrlý, Josef (advisor)
Objective of this bachelor´s thesis was to create literary background research in area of kinetic energy recovery systems during braking and subsequent start of vehicles. The first part is dedicated to splittage and suitability of using methods of kinetic energy recovery. The second part of this thesis is explains principle and using electrical, mechanical-elctric and mechanical methods for cars. The third part is about principal and using hydraulic methods for refuse truck and forklifts.
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Models and simulations of processes of emission-free wheel loader with electric drive
Cieslar, Filip ; Nevrlý, Josef (referee) ; Němec, Zdeněk (advisor)
This diploma thesis deals with the creation of models simulating the processes of an emission-free wheel loader, which was created by rebuilding the original version with a combustion engine. Part of the work is the methodical creation of models from the basic part of the machine to a simplified model of the overall machine, its functional verification and calibration based on available information’s and measurements. In this paper, selected parameters of the overall machine model are verified based on performed measurements, the suitability of selected components is verified, and the optimization and modification of the model is performed based on verification. The aim of the thesis is to present the simulation and verification procedure and its practical use in the development of an emission-free wheel loader with electric drive.
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Optimisation of Flow Rates in Lubrication Systems with Progressive Distributors by means of Genetic Algorithms
Vepřek, Jiří ; Pavlok, Bohuslav (referee) ; Bauer, František (referee) ; Habán, Vladimír (referee) ; Nevrlý, Josef (advisor)
This doctoral thesis presents the results of the development of two software programs for the design of progressive distributors and progressive lubrication systems. One of these programs implements a genetic algorithm and the other, which is used to design progressive lubrication systems, implements a parallel genetic algorithm of the island model. The program for the design of progressive distributors was implemented in Java using the NetBeans development environment and the other program was created in Matlab. The thesis further focuses on analytical and computational solutions of the flow of compressible greases seen as viscoplastic fluids. Equations for the numerical solution of the non-steady flow of compressible viscoplastic Bingham fluids were derived and solved by the Lax-Wendroff method in Matlab. As several constants had to be set in the equations, experiments were conducted with the ecological grease Plantogel 2S in the laboratory of the Kaplan Department of Hydraulic Machines, mainly to determine the sound velocity in this grease. The sound velocity was calculated based on the experimental results by applying Fourier transformation and the transition matrix method. In addition to this, the rheological measurements of greases were used. As seen from the results, the ecological greases are actually thixotropic viscoplastic fluids with a significant elastic element. Since a Newton fluid was assumed when calculating the sound velocity, the possibilities of using the transition matrix method for viscoplastic fluids were then considered. No analytical solution of the flow of viscoplastic fluids in a frequency spectrum has been published so far. Because it emerged that greases had a significant elastic stress factor, the problem of the non-steady flow of elastic-viscoplastic fluids was solved numerically between two infinite parallel plates by applying the finite difference method (FDM). The computation was done in Matlab. This doctoral thesis makes a contribution to solving problems related to the design of progressive distributors and progressive lubrication systems used to distribute compressible greases. Considering the complex approach to this field and the achieved results, the thesis also represents a significant contribution to design work.
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Accurate positioning of pneumatic drives
Volf, Marek ; Nevrlý, Josef (referee) ; Marada, Tomáš (advisor)
Thesis starts with brief overview of the present role of pneumatic actuators. Further research is carried out in modelling and control of pneumatic actuators. A basic overview of thermodynamic laws is presented. These laws are used to assemble a mathematical model of the pneumatic drive. Subsequently the identification of model parameters is shown. A controller is propřed using fuzzy PID algorithms. Results are compared with the conventional PID controller.
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Determination of efficiency of hydraulic drive with recuperation
Kobza, Michal ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
In the first part of the thesis is determined efficacy criterion for the individual operating modes of the experimental stand with energy recovery and subsequently are evaluated the records of individual measurements. Energy savings are calculated with using energy recovery. The second part describes the process of digitizing relative fuel consumption map of the engine. Results are confronted with a real application engine in the road roller Ammann AP 240 H. In addition, the master thesis describes the creation of hydrostatic converter block in the program MATLAB/Simulink 2012b. Creating block can be used in the development of simulation models.
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Equipment to vehicles energy recovery simulation
Ranuša, Matúš ; Jurík, Miroslav (referee) ; Nevrlý, Josef (advisor)
The bachelor thesis deals with design and construction of an experimental device – stand for simulation and recovery energy at utility vehicles. The first parts of the thesis describe principle and process of experiment in the University of Wisconsin Madison and thesis deals with selection of hydraulic components in cooperation with company Bosch Rexroth. The second part of the thesis deals with calculation and construction proposal of the flywheel which meets the requirements of mathematical model and other parts of model. Result of the thesis is complete 3D model of experiment stand suitable for tests energy recovery in applications. Precise determination of the effectiveness of hydrostatic recovery is one of the objectives of experiments that will be implemented at the test stand.
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Analysis and optimalization of pneumatic system of race pneumobile
Navrátil, Lukáš ; Nevrlý, Josef (referee) ; Ranuša, Matúš (advisor)
This thesis deals with the theoretical design of the new pneumatic system, which should lead to increased performance and fuel racing pneumobilu Blowfish. After the theoretical proposal deals with the analysis of both the new pneumatic circuit, and the old pneumatic circuit. The culmination of this work will be participating in the competition with the pneumobil in Hungary, Eger. The first part describes the current state pneumobilu contest and its rules. Further there are described in detail pneumatic elements that are used to pneumobilu. In the second part contains measurements that verify the effectiveness of the new pneumatic circuit.
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Test bench for analysis of energy recovery in experimental vehicle
Indruch, Jiří ; Čermák, Jan (referee) ; Nevrlý, Josef (advisor)
The diploma thesis deals with design of an experimental test bench for recovery energy simulation at machines with hydrostatic energy transmission. This work describes choice of connection and selection of hydrostatic and other components. A first part of the thesis deals with calculation and design of the flywheel whose is its rotational kinetic energy corresponds in a certain scale to translational kinetic energy of the experimental vehicle. The thesis outlines the efficiency of transformation of rotational kinetic energy to pressure energy its accumulation and subsequent conversion back to rotational kinetic energy. Precise determination of the effectiveness of hydrostatic recovery is one of the objectives of experiments that will be implemented at the test bench. The task of the measurement and physical-technical analysis to be conducted at the manufactured test bench is primarily to obtain data at for the precise control of the hydrostatic energy recovery system to maximize its efficiency.
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