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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Modelling and Validation of a Truck Cooling System

Nordlander, Erik January 2008 (has links)
In the future, new challenges will occur during the product development in the vehicular industry when emission legislations getting tighter. This will also affect the truck cooling system and therefore increase needs for analysing the system at different levels of the product development. Volvo 3P wishes for these reasons to examine the possibility to use AMESim as a future 1D analysis tool. This tool can be used as a complement to existing analysis methods at Volvo 3P. It should be possible to simulate pressure, flow and heat transfer both steady state and transient. In this thesis work a cooling system of a FH31 MD13 520hp truck with an engine driven coolant pump is studied. Further a model of the cooling system is built in AMESim together with necessary auxiliary system such as oil circuits. The model is validated using experimental data that have been produced by Volvo 3P at the Gothenburg facility. The results from validation and other simulations show that the model gives a good picture of the cooling system. It also gives information about pressure, flow and heat transfer in steady state conditions. Further a design modification is done, showing how a change affects the flow in the cooling system. The conclusion is that a truck cooling system can be built and simulated in AMESim. Further, it shows that AMESim meets the requirements Volvo 3P in Gothenburg has set up for the future 1D analysis tool and thereby AMESim is a good complement to the already existing analysis method.
32

MODELLING AND OPTIMIZATION OF AN ADSORPTION COOLING SYSTEM FOR AUTOMOTIVE APPLICATIONS

Verde Trindade, María 01 September 2015 (has links)
[EN] This PhD study deals with the modelling of an adsorption system designed to provide air conditioning for vehicles, and is driven by the waste heat available from the water/glycol cooling circuit of the engine. The system is based on the sequential heating/cooling of two sorption beds containing a solid sorption material which desorbs or adsorbs water vapour. The condensation of the vapour is carried out by a cooling circuit while the subsequent evaporation of the condensed liquid is employed to produce the cooling effect, generating chilled water, which is then employed to cool down the air of the cabin. The developed model is fully dynamic and is based on zero-dimensional lumped parameter models for all the necessary components of the overall system including the engine, the beds, the heating circuit, the cooling circuit, the chilled water circuit and the vehicle cabin. The sorption bed model takes into account the non-equilibrium of the adsorption and desorption processes and is able to work with any kind of adsorbent materials, but the study has been restricted to silica gel and zeolite which are among the most appropriate materials for this application. The model is employed to simulate a standard driving cycle of a vehicle, evaluating the instantaneous available heat from the engine cooling system and the dynamic behaviour of the described sorption A/C system, resulting in the estimation of the evolution of the cabin temperature along the cycle. The model of the overall system has been developed under the MATLAB Simulink programming environment. The model of the adsorption system has been first validated against experimental results, showing its excellent capabilities to predict the dynamic behaviour of the system. The model was then used to analyse the influence of the main design parameters of the bed and the main operation parameters on the system's performance: cooling capacity and coefficient of performance (COP). This was done in order to provide rules for the optimal design and operation of this kind of systems. Finally, the model has been employed to analyse the overall system (engine, adsorption system, heating and cooling circuits, chilled water circuit and cabin) performance along a standard driving cycle, under various operation strategies with regards to the initial state of the adsorbent material in the beds, and operation conditions both for a car and a truck. The results show the difficulties of activating the system at the initial periods of the cycle, when the engine is warming up, and the difficulties to synchronise the operation of the system with the availability of waste energy. They also highlight the limitation in capacity of the designed system, showing that it would not able to fulfil the comfort requirements inside the cabin in hot days or after soaking conditions. Part of this PhD study was carried out in the frame of an R&D project called "Thermally Operated Mobile Air Conditioning Systems - TOPMACS", financially supported by the EU under the FP6 program, which was devoted to the evaluation of the feasibility and performance of potential sorption system solutions for the air conditioning of vehicles. / [ES] Esta tesis doctoral se centra en el modelado de un sistema de adsorción diseñado para proporcionar aire acondicionado de vehículos a partir del calor residual disponible en el circuito de refrigeración de agua/glicol del motor. El sistema se basa en el calentamiento/enfriamiento secuencial de dos reactores que contienen un material adsorbente sólido que desorbe o absorbe vapor de agua. La condensación del vapor se lleva a cabo mediante un circuito de refrigeración, mientras que la posterior evaporación del agua condensada se emplea para producir agua fría, que se emplea finalmente en enfriar el aire de la cabina. El modelo desarrollado es completamente dinámico y se basa en modelos cero dimensionales de parámetros concentrados, para todos y cada uno de los componentes del sistema global incluyendo el motor, los reactores, el circuito de calentamiento, el circuito de enfriamiento, el circuito de agua fría y la cabina del vehículo. El modelo del reactor contempla el no equilibrio de los procesos de adsorción o desorción y es capaz de trabajar con cualquier par de materiales adsorbentes. No obstante el estudio se ha restringido a gel de sílice y zeolita que se encuentran entre los materiales más adecuados para esta aplicación. El modelo se emplea para simular un ciclo de conducción estándar del vehículo, evaluando el calor disponible instantáneamente en el sistema de refrigeración del motor, y el comportamiento dinámico del sistema descrito adsorción-Aire Acondicionado, permitiendo como resultado principal la estimación de la evolución de la temperatura de la cabina a lo largo el ciclo. El modelo del sistema global se ha desarrollado en el marco del entorno de programación MATLAB Simulink. El modelo del sistema de adsorción se ha validado primero contra resultados experimentales demostrando las excelentes capacidades del modelo para predecir el comportamiento dinámico del sistema. A continuación, el modelo se ha aplicado para analizar la influencia de los principales parámetros de diseño del reactor, y de los principales parámetros de operación, sobre el rendimiento del sistema: la capacidad y coeficiente de operación (COP), con el fin de proporcionar directrices para el diseño y operación óptima de este tipo de sistemas. Por último, el modelo ha sido empleado para analizar el funcionamiento y prestaciones del sistema en su conjunto (motor, sistema de absorción, los circuitos de calefacción y refrigeración, circuito de agua fría, y la cabina) a lo largo de un ciclo de conducción estándar, bajo diferentes estrategias de operación en lo que se refiere al estado inicial del material adsorbente en los reactores, y las condiciones de operación, para el caso de un coche, y para el de un camión. Los resultados muestran las dificultades de la activación del sistema en los periodos iniciales del ciclo, cuando el motor se está calentando, y las dificultades para sincronizar el funcionamiento del sistema con la disponibilidad de energía térmica excedente del motor, así como la limitación en la capacidad de enfriamiento del sistema diseñado, que no resulta capaz de satisfacer los requerimientos mínimos de confort dentro de la cabina en los días calurosos o de enfriarlo con suficiente rapidez cuando el vehículo ha estado estacionado bajo el sol durante varias horas. Parte de este estudio de doctorado se ha llevado a cabo en el marco de un proyecto de I + D denominado " Thermally Operated Mobile Air Conditioning Systems - TOPMACS", financiado parcialmente por la UE en el marco del programa FP6, y que perseguía la evaluación de la viabilidad y el potencial de aplicación de soluciones de sistemas de adsorción activadas por el calor residual del motor para el aire acondicionado de vehículos. / [CAT] Aquesta tesi doctoral es centra en el model d'un sistema d'adsorció dissenyat per a proporcionar aire acondicionat a vehicles a partir de la calor residual disponible al circuit de refrigeració d'aigua / glicol del motor. El sistema es basa en l'escalfament / refredament seqüencial de dos reactors que contenen un material adsorbent sòlid que desorbeix o absorbeix vapor d'aigua. La condensació del vapor es porta a terme mitjançant un circuit de refrigeració, mentre que la posterior evaporació de l'aigua condensada s'utilitza per a produir aigua freda, que s'empra finalment en refredar l'aire de la cabina. El model desenvolupat és completament dinàmic i es basa en models zero dimensionals de paràmetres concentrats, per a tots i cada un dels components del sistema global incloent el motor, els reactors, el circuit d'escalfament, el circuit de refredament, el circuit d'aigua freda i la cabina del vehicle. El model del reactor contempla el no equilibri dels processos d'adsorció o desorció i és capaç de treballar amb qualsevol parell de materials adsorbents. No obstant això, l'estudi s'ha restringit a gel de sílice i zeolita que es troben entre els materials més adequats per a aquesta aplicació. El model s'utilitza per a simular un cicle de conducció estàndard del vehicle, avaluant la calor disponible instantàniament en el sistema de refrigeració del motor, i el comportament dinàmic del sistema descrit Adsorció-Aire Acondicionat, permetent com a resultat principal l'estimació de l'evolució de la temperatura de la cabina al llarg del cicle. El model del sistema global s'ha desenvolupat en l'entorn de programació MATLAB Simulink. El model del sistema d'adsorció s'ha validat primer amb resultats experimentals demostrant les excel¿lents capacitats del model per a predir el comportament dinàmic del sistema. A continuació, el model s'ha aplicat per analitzar la influència dels principals paràmetres de disseny del reactor, i dels principals paràmetres d'operació, sobre el rendiment del sistema: la capacitat i coeficient d'operació (COP), amb la finalitat de proporcionar directrius per al disseny i operació òptima d'aquest tipus de sistemes. Finalment, el model ha estat utilitzat per analitzar el funcionament i prestacions del sistema en el seu conjunt (motor, sistema d'absorció, els circuits de calefacció i refrigeració, circuit d'aigua freda, i la cabina) al llarg d'un cicle de conducció estàndard, sota diferents estratègies d'operació pel que fa a l'estat inicial del material adsorbent en els reactors, i les condicions d'operació, per al cas d'un cotxe, i per al d'un camió. Els resultats mostren les dificultats de l'activació del sistema en els períodes inicials del cicle, quan el motor s'està escalfant, i les dificultats per sincronitzar el funcionament del sistema amb la disponibilitat d'energia tèrmica excedent del motor, així com la limitació en la capacitat de refredament del sistema dissenyat, que no resulta capaç de satisfer els requeriments mínims de confort dins de la cabina en els dies calorosos o de refredar amb suficient rapidesa quan el vehicle ha estat estacionat sota el sol durant diverses hores. Part d'aquest estudi de doctorat s'ha dut a terme en el marc d'un projecte d'I + D denominat "Thermally Operated Mobile Air Conditioning Systems - TOPMACS", finançat parcialment per la UE en el marc del programa FP6, i que perseguia l'avaluació de la viabilitat i el potencial d'aplicació de solucions de sistemes d'adsorció activats per la calor residual del motor per a l'aire condicionat de vehicles. / Verde Trindade, M. (2015). MODELLING AND OPTIMIZATION OF AN ADSORPTION COOLING SYSTEM FOR AUTOMOTIVE APPLICATIONS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54120 / TESIS
33

Optimalizace chladicího systému letounů / Airplane Cooling System Optimization

Lajza, Ondřej January 2017 (has links)
Dissertation thesis is focused on the aircraft cooling system optimization. The knowledge of the pressure loss is necessity for design of an optimal system. In the beginning of the thesis, the different designs of piston engine cooling systems are described for both aircrafts and automobiles. Other sections outline the determination of the coolers characteristics and describe the different test sections applicable for the characteristics measurement. The test section built at the Institute of the aerospace engineering is described as well. Practical part of the thesis describes the calibration of the test section. The measurements of the specific coolers were compared with the CFD simulation of two models - the simplified cooler model and cooler element model. Additionally, the measurements were compared with results obtained at specialized coolers testing facility.
34

Nekonvenční chladicí systémy pro Formuli Student / Unconventional Cooling Systems for Formula Students

Ondrejka, Filip January 2021 (has links)
This master’s thesis deals with the design and manufacture of a heat exchanger with polymeric hollow fibers for a Formula Student vehicle. The work can be divided into three parts. The first part contains a review of heat transfer and heat exchangers, the second part deals with polymeric fiber heat exchangers design and manufacture of of polymeric hollow fibers heat exchanger with a heat exchanger for a Formula Student vehicle. The last part deals with the comparison of polymeric hollow fibers heat exchanger with the original aluminum heat exchanger and the evaluation of the measurement results.
35

Technologické, ekonomické a ekologické aspekty obrábění s vysoce výkonným chlazením / Technological, economical and ecological aspects of high efficient cooling

Hort, Martin January 2009 (has links)
The diploma thesis is aimed to the influence of the high-pressure and low-pressure coolant system according to the machining operation. The comparison was carried out with different types of materials and cutting tools using the main machining operations – turning, milling, and drilling. The study is focused on the chip and heat removal from the cutting zone, tools life and wear of the tools. A description of the basic principle of the high-pressure coolant system meant is described in this thesis. The economical analysis of the high-pressure compared to low-pressure system was determined in the last part of this work.
36

Chladicí okruh pro formulový motor / Water Cooling System for Formula Engine

Bastl, Ondřej January 2013 (has links)
Diploma thesis is focused on design engine cooling system for formula vehicle type. The aim is introduce with cooling systems of Formula Student/SAE car and competition rules. Based on the famous engine determine the initial conditions for the cooling system. In addition to design all parts of the cooling system and check affordability.
37

Kylning av yttersula med hjälp av additiv tillverkning / Cooling system for a shoe sole using additive manufacturing

Anderberg, Axel, Esping, Jonatan January 2019 (has links)
Innovation genom additiv tillverkning sker snabbt i dagens industri där snabb prototyptillverkning är något som additiv tillverkning lämpar sig bäst för. Däremot utforskas möjligheter för tillverkning av detaljer med funktionellt syfte då additiv tillverkning möjliggör mer komplicerad design än traditionella tillverkningsmetoder. Med de miljöproblem som förekommer i dagens samhälle ger det upphov till extrema väderförhållanden, exempelvis skogsbränder. Givet det så har detta projekt utforskat möjligheten av att genom additiv tillverkning konstruera en sula med ett inbyggt kylsystem i syfte att kyla foten under förlängd arbetstid i omgivning med hög temperatur. Kravet som ställdes på sulan var att i en omgivning med hög temperatur skall sulan kunna kyla mer än en traditionell sula över en period på 8 timmar. Med hjälp av CAD- och FEM-program analyserades tre primära modeller med avseende på temperaturutväxling samt belastning, varav dessa tre modeller ställdes i relation till en traditionell sula utan kylsystem. Resultaten hänvisar till att med de krav som ställdes på sulan ges en högre kylningseffekt vid två av tre av dessa modeller relativt en traditionell sula. Dessutom finns potential för fortsatt utveckling av liknande sulor med avseende på specialtillverkning. / Innovation through additive manufacturing occurs quickly in today’s industry where rapid prototyping is something that additive manufacturing excels at. However, research is being made to explore the ability for manufacturing components with functional use, where additive manufacturing makes more complex design possible in relation to traditional manufacturing methods. With the environmental problem that occurs in today’s world comes more extreme weather conditions, for example forest fires. With that as a basis, this project has explored the possibility of creating the sole of a shoe with a built-in cooling system, using additive manufacturing, for the purpose of extended work in an environment with a high temperature. The requirements put on the sole was that in an environment of high temperature the sole should be able to help reduce temperature inside the shoe itself over the course of an eight-hour workday. Three primary models were analysed in terms of transient temperature as well as load and deformation with the help of CAD and FEM programs, where these three soles were compared to a sole without any form of cooling system. The results show that with the parameters of the project, a greater cooling effect is achieved in two of the three models, compared to a regular sole. Furthermore, there is the potential for continued development of similar models of soles with respect to specific demands in fields such as hiking.
38

Novel System Design For Residential Heating And Cooling Load Shift Using PCM Filled Plate Heat Exchanger And Auxiliaries For Economic Benefit And Demand Side Management

Yaser, Hussnain A. 27 October 2014 (has links)
No description available.
39

Optimization of a paraffin cooling system for an automated tissue embedding center

Landis, Adam January 2004 (has links)
No description available.
40

Modeling, Analysis, and Experimental Validation of an Electric Linear Series Elastic Actuator for an Exoskeleton

Pang, Zhoubao 26 June 2020 (has links)
Exoskeletons and humanoid robots require high-power, low-weight, and back-driveable actuators. This paper describes the design and analysis of a high-force linear series elastic actuator for a lower body exoskeleton. The actuator is powered by two motors and utilize a liquid cooling system to increase its maximum continuous torque. The actuator is capable of outputting a maximum continuous force of 4800N and a maximum speed of 0.267 m/s with a maximum continuous motor current of 18A. The Titanium leaf spring was used in the actuator to provide compliance. The spring has a median stiffness of 587 N/mm with standard deviation of 38 N/mm, validated by experiments. Dynamic model was created to analyze the normal modes and can be used for developing model-based controllers. / Master of Science / Compliant Linear actuators with ball screw have become popular for humanoids robots and exoskeleton. The use of ball screw lead to high efficiency, high gear ratio and high back-drivability. The compliance or the ''softness'' of the actuator comes from Titanium leaf spring, which can storage energy during gait cycle and protect motor and the ball screw from impacts of walking. The custom liquid cooling system improves the force density for the actuator. Beam theory analysis, heat transfer analysis, and dynamics analysis were performed to provides insights for the actuator system.

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