<p>This thesis focuses on the use of multiple redundant control surfaces to increase performance during flight. There is no clear-cut definition of performance. It may differ between applications, but here, the amount of drag for a given flight condition is used. The work is concentrated on minimizing drag with the use of measurements instead of numerical simulations. Measured data contains noise and there are problems with repeatability and hysteresis. These difficulties are considered and a method for drag minimization during flight is presented.</p><p>In the first study the drag minimization algorithm is discussed. Focus is put on describing the implemented method and the treatment of constraints to the optimization problem. The constraints include keeping the lift constant as well as having bounds on the control surface deflections.</p><p>In the second work, a more complex wind tunnel model is used to validate the drag optimization algorithm. Drag reduction for different flight conditions is studied, as well as the impact of the number of control surfaces. Different layouts of the control surfaces are also tested. The results show that the constraints are satisfied and that the drag is reduced substantially.</p>

This thesis focuses on the use of multiple redundant control surfaces to increase performance during flight. There is no clear-cut definition of performance. It may differ between applications, but here, the amount of drag for a given flight condition is used. The work is concentrated on minimizing drag with the use of measurements instead of numerical simulations. Measured data contains noise and there are problems with repeatability and hysteresis. These difficulties are considered and a method for drag minimization during flight is presented. In the first study the drag minimization algorithm is discussed. Focus is put on describing the implemented method and the treatment of constraints to the optimization problem. The constraints include keeping the lift constant as well as having bounds on the control surface deflections. In the second work, a more complex wind tunnel model is used to validate the drag optimization algorithm. Drag reduction for different flight conditions is studied, as well as the impact of the number of control surfaces. Different layouts of the control surfaces are also tested. The results show that the constraints are satisfied and that the drag is reduced substantially. / QC 20101116

No description available.

Thermal management is a rapidly growing field in power electronics today. As power supply systems are designed with higher power density levels, keeping component temperatures within suitable ranges of their maximum operating limits becomes an increasingly challenging task. This project focuses on thermal management at the system level, using a 1.2 kW front-end power converter as a subject for case study. The establishment of a methodology for using the computer code I-deas to computationally simulate the thermal performance of component temperatures within the system was the primary goal. A series of four benchmarking studies was used to verify the computational predictions. The first test compares predictions of a real system with thermocouple measurements, and the second compares computational predictions with infrared camera and thermocouple measurements on a component mounted to a heat sink. The third experiment involves using flow visualization to verify the presence of vortices in the flow field, and the fourth is a comparison of computational temperature predictions of a DC heater in a controlled flow environment. A radiation study using the Monte Carlo ray-trace method for radiation heat transfer resulted in the reduction of some component temperature predictions of significant components. This radiation study focused on an aspect of heat transfer that is often ignored in power electronics. A component rearrangement study was performed to establish a set of guidelines for component placement in future electronic systems. This was done through the use of a test matrix in which the converter layout was varied a number of different ways in order to help determine thermal effects. Based on the options explored and the electrical constraints on the circuit, an optimum circuit layout was suggested for maximum thermal performance. This project provides a foundation for the thermal management of power electronics at the system level. The use of I-deas as a computational modeling tool was explored, and comparison of the code with experimental measurements helped to explore the accuracy of I-deas as a system level thermal modeling tool. / Master of Science

<p>Modelling combustion engines is an important tool in engine research. Development and modelling of ionization current has potential in developing virtual pressure sensors based on ionization measurements. Previous models has problem when predicting the true relationshipbetween the pressure peak location and ionization peak location, and both too early and too late predictions has been observed. An explanation for these discrepancies are provided and a model where the experimental mismatch has been reduced to less than one CAD is also presented. This is well within the measurement uncertainty.</p>

Modelling combustion engines is an important tool in engine research. Development and modelling of ionization current has potential in developing virtual pressure sensors based on ionization measurements. Previous models has problem when predicting the true relationshipbetween the pressure peak location and ionization peak location, and both too early and too late predictions has been observed. An explanation for these discrepancies are provided and a model where the experimental mismatch has been reduced to less than one CAD is also presented. This is well within the measurement uncertainty.

No description available.

Due to its unique features such as controllable power factor, controllable bi-directional power flow, and rapid dynamic response, Voltage Source Converters (VSCs) have been widely used in various industrial applications such as distributed generation systems, power distribution systems, uninterruptible power supplies (UPS), AC motor drives, etc. To optimize the performance of the VSC, many control algorithms have been proposed. This thesis investigates development of the nonlinear control for the VSC in two applications: power factor control and active power filtering. A detailed description of the dynamic model of the VSC system is presented in different reference frames. A linearization-based control scheme is introduced for power factor regulation and verified by switched simulation and real-time experiment on a test stand which has been constructed at the Applied Nonlinear Control Lab (ANCL), University of Alberta. In addition, an internal model-based control scheme is introduced to perform active power filtering. This algorithm is verified by simulation. / Controls

his thesis deals with the problems of cavitation flow in a Venturi tube. It is made for a multi-phase (water-vapour) flow calculation of two geometry tubes. Results of numerical calculations for the flow geometry (dimensions) are compared with performed experiment. Numerical flow calculation was performed in the Fluent 2.3.26.

This licentiate thesis considers the modelling, simulation and experimental investigation of a rammer compactor machine. The purpose is to develop an efficient and verified method for simulation of rammer compactor machines to be used in the product development process. The experience gained through this work is also intended to be useful for studying other types of dynamic compactor machines. Rammer compactor machines perform impact soil compaction. This is more efficient than static compaction. The machines are often used in places where a high degree of compaction is needed, and where the space for operation is limited. The complexity of this type of machine makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for predicting the dynamic behaviour of the machine. To be useful for optimisation the theoretical model and simulation procedure must be verified. By concurrently working with theoretical modelling, simulations, experimental verifications, and optimisation an efficient analysis support for product development is achieved. This co-ordination works both ways in an iterative manner: experimental investigations are used to verify theoretical models and simulations; and theoretical models and simulations are used to design good experiments. This Complete Approach concept enables better decisions to be made earlier on in the development process, resulting in a decrease in time-to-market and improved quality. In this thesis, the Complete Approach concept is applied to a rammer soil compactor machine. An introductory iteration is described. The good agreement between theoretical and experimental results indicates that the theoretical model and simulation procedure should prove useful in introductory optimisation studies. The thesis discusses reasons for the remaining discrepancy and suggests improvements in both the theoretical model and the experimental set-up for future iterations. / I arbetet studeras det dynamiska beteendet av en jordpackningsmaskin. Syftet är att bygga upp en verifierad modell som kan ligga till grund för vidare produktutveckling. Ett samordnat arbetsätt, Complete Aproach / <p>http://epubl.luth.se/1402-/02/index.html</p>