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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.
1

Investigação da indução de engasgamento em tubeira DeLAVAL para motor-foguete por intermédio do prolongamento da garganta / Investigation of choking induction in a DeLaval nozzle of a rocket motor by a means of extending the throat lenght

Izola, Dawson Tadeu 17 October 2013 (has links)
A condição ótima de funcionamento de uma tubeira em um motor foguete com escoamento isentrópico, implica que a velocidade na garganta (seção de menor área) seja equivalente à velocidade do som local, condição de Mach 1 e bocal engasgado. Pode-se alcançar essa condição reduzindo a área da seção do escoamento até a área crítica, velocidade sônica. Após a garganta acontece a expansão e se alcança velocidades supersônicas no divergente. Para manter a condição de Mach 1 na garganta em motores foguetes, trabalha-se com pressões superiores à necessária para se engasgar o bocal. Isto ocorre porque tenta-se compensar instabilidades ou variações de volumes produzidos na combustão ou queima. Usando uma pressão de trabalho maior, impõe-se que a condição de Mach 1 fique mantida durante toda a queima do combustível, isso implica em usar tubos mais resistentes à pressão e maior massa do tubo-motor. Observou-se experimentalmente que em algumas situações construtivas se podem modificar a pressão e temperatura necessárias para engasgar o bocal aumentando o comprimento da garganta. O comprimento do estrangulamento pode estabelecer uma condição para formação e evolução da camada limite e esta condição restringir a área nominal, modificando o regime do escoamento. Um equipamento especialmente desenvolvido para esse ensaio compara resultados de cinco modelos de motores, divididos em dois grupos, cada grupo com áreas de entrada, garganta e saída iguais, porém com comprimentos diferentes de garganta. Em análise experimental, observou-se que a pressão de trabalho e a temperatura são influenciadas pelo comprimento da garganta, interferindo na relação entre as pressões internas e de garganta e apresentando condições de engasgamento mensuráveis. Essas medidas foram conduzidas no presente estudo de doutorado. / The optimum operational condition of a rocket motor nozzle with isentropic flow implies that the velocity at the throat (the section with smallest area) is equivalent to the speed of the local sound. This speed is also called Mach 1 and it is said that at this condition the nozzle is choking. One can achieve this condition by reducing the cross-sectional area of the flow to the critical area resulting in a sonic speed. Beyond the nozzle throat, in the divergent section of the motor, flow expansion occurs and reaches supersonic speeds. To maintain the condition of Mach 1 at the throat, higher pressures than the one necessary to choke the nozzle are applied. This practice is done in order to compensate for jitter or variations of volumes produced in the combustion process. Using a higher operating pressure guarantees that a Mach 1 speed is maintained throughout the combustion process. Consequently, due to this higher operating pressure, more resistant tubes are needed to withstand this higher pressure and an increase in the motor weight is inevitable. It was observed experimentally that some constructional modifications of the motor can alter the pressure and temperature required for choking. This was noted with increasing the bottleneck length of the nozzle throat which was able to establish a condition for the formation and evolution of the boundary layer, restricting the nominal area and thus modifying the flow regime. In this study, the results of five engine models are compared using a specially designed equipment. The rockets were divided into two groups, each with equal inlet, throat, and exit areas, but having different throat lengths. In experimental analysis, it was observed that the working pressure and temperature are influenced by the length of the throat, interfering in the relationship between the internal pressures and throat presenting measurable choking conditions which were conducted in this doctorate thesis study.
2

Investigação da indução de engasgamento em tubeira DeLAVAL para motor-foguete por intermédio do prolongamento da garganta / Investigation of choking induction in a DeLaval nozzle of a rocket motor by a means of extending the throat lenght

Dawson Tadeu Izola 17 October 2013 (has links)
A condição ótima de funcionamento de uma tubeira em um motor foguete com escoamento isentrópico, implica que a velocidade na garganta (seção de menor área) seja equivalente à velocidade do som local, condição de Mach 1 e bocal engasgado. Pode-se alcançar essa condição reduzindo a área da seção do escoamento até a área crítica, velocidade sônica. Após a garganta acontece a expansão e se alcança velocidades supersônicas no divergente. Para manter a condição de Mach 1 na garganta em motores foguetes, trabalha-se com pressões superiores à necessária para se engasgar o bocal. Isto ocorre porque tenta-se compensar instabilidades ou variações de volumes produzidos na combustão ou queima. Usando uma pressão de trabalho maior, impõe-se que a condição de Mach 1 fique mantida durante toda a queima do combustível, isso implica em usar tubos mais resistentes à pressão e maior massa do tubo-motor. Observou-se experimentalmente que em algumas situações construtivas se podem modificar a pressão e temperatura necessárias para engasgar o bocal aumentando o comprimento da garganta. O comprimento do estrangulamento pode estabelecer uma condição para formação e evolução da camada limite e esta condição restringir a área nominal, modificando o regime do escoamento. Um equipamento especialmente desenvolvido para esse ensaio compara resultados de cinco modelos de motores, divididos em dois grupos, cada grupo com áreas de entrada, garganta e saída iguais, porém com comprimentos diferentes de garganta. Em análise experimental, observou-se que a pressão de trabalho e a temperatura são influenciadas pelo comprimento da garganta, interferindo na relação entre as pressões internas e de garganta e apresentando condições de engasgamento mensuráveis. Essas medidas foram conduzidas no presente estudo de doutorado. / The optimum operational condition of a rocket motor nozzle with isentropic flow implies that the velocity at the throat (the section with smallest area) is equivalent to the speed of the local sound. This speed is also called Mach 1 and it is said that at this condition the nozzle is choking. One can achieve this condition by reducing the cross-sectional area of the flow to the critical area resulting in a sonic speed. Beyond the nozzle throat, in the divergent section of the motor, flow expansion occurs and reaches supersonic speeds. To maintain the condition of Mach 1 at the throat, higher pressures than the one necessary to choke the nozzle are applied. This practice is done in order to compensate for jitter or variations of volumes produced in the combustion process. Using a higher operating pressure guarantees that a Mach 1 speed is maintained throughout the combustion process. Consequently, due to this higher operating pressure, more resistant tubes are needed to withstand this higher pressure and an increase in the motor weight is inevitable. It was observed experimentally that some constructional modifications of the motor can alter the pressure and temperature required for choking. This was noted with increasing the bottleneck length of the nozzle throat which was able to establish a condition for the formation and evolution of the boundary layer, restricting the nominal area and thus modifying the flow regime. In this study, the results of five engine models are compared using a specially designed equipment. The rockets were divided into two groups, each with equal inlet, throat, and exit areas, but having different throat lengths. In experimental analysis, it was observed that the working pressure and temperature are influenced by the length of the throat, interfering in the relationship between the internal pressures and throat presenting measurable choking conditions which were conducted in this doctorate thesis study.
3

Anordning för rengöring avkomponent i mjölkningsrobot : Framtagning av lösning för förbättrad rengöring avspentvättkopp för att motverka bakterietillväxt / Device for cleaning of component in milking robot : Design of solution for improved cleaning of teat cleaningcup to prevent bacterial growth

Lindbom, Erik January 2017 (has links)
This report describes how to make the VMS teat cleaning cup clean itself properly.The purpose is to create a sulotion that make sure the whole cup gets washedduring normal cleaning. The solution should be compatible with earlier versionsof the VMS and will be tested to see if the amount of bacteria decreases. / Denna rapport behandlar problemet med att en ny version av spentvättkopp på både dagens och framtida VMS (Volontary milking system) inte görs rent ordentligt. Syftet med projektet var att ta fram en lösning som låter hela spentvättkoppen göras rent när den inte används. Den färdiga versionen ska kunna testas ingående i en verklig miljo på olika generationer av VMS:er. Syftet med detär att kontrollera att lösningen klarar av långvarigt bruk och att göra en jämförelse för att se om mängden bakterier minskar. Ytterligare ett syfte var att göra prototypen lätt att montera utan att behöva modiera den existerande maskinen. Resultatet blev tre varianter på grund av olika designval på tidigare versioner.
4

An Interface between Packaging and Logistics systems A case study performed in DeLaval

Gunasekaran, Sri Hari January 2012 (has links)
Purpose As a result of globalization competition in every business has raised. This makes it imperative to show at most attention towards every part of the business process in a detailed manner. The ratio between the cost of the industrial equipment and the cost expended in packaging and repairing the damages incurred in the logistics of the equipment is very little. As a result, in current practice packaging design is not given substantial attention it deserves. Because of this several manufacturing industries incur expensive losses and degradation of their brand value primarily due of inferior packaging practices. Therefore this thesis focuses on importance of packaging in the industries and its relationship with logistics system. Problem This thesis have answered following research questions 1. How does the interaction happen between the packaging system and other systems in a manufacturing industry? 2. What are the steps that can be taken to establish an effective relationship between packaging and logistics? 3. What are the relevant key performance indicators (KPI) which affects the company’s logistics costs in context with packaging? Methodology Facts and data for this paper were gathered from literature reviews of various articles found in international journals and case studies. In addition semi-structured interviews were conducted with representatives at manufacturing industries. Basically systematic approach and qualitative research are the main two methodology followed. The course of this thesis project was executed during the period of five months at M/s. Delaval International AB, an attempt was made to investigate the effectiveness of different types of packaging solutions that can be adopted to improve the current packaging process. Discussions Below four sections where mainly discussed in this thesis 1. Optimizing logistics by better packaging 2. Increase of packaging logistics knowledge and importance in the entire organization 3. Influence of packaging 4. Information flow and exchange between packaging and logistics systems The basic values of the packaging logistics and the interactions between packaging and logistics where also discussed.
5

Problematika dojicích robotů DeLaval

ŠVEC, Tomáš January 2019 (has links)
The content of this thesis is focused on the performance evaluation of the DeLaval milking robot in the selected stable. For this work was chosen the family farm stable of Mr. Šítal in the village Mojné. Selected parameters of milking robotic were monitored from 19.9.2018 to 18.3.2019 and on the base of these parameters was evaluated efficiency of the equipment. In this time were followed numbers of milked cows per 24 hours, the average numbers of milking on one cow, the average milking time and daily milk utility. In the selected stable were in a half-year time milked averagely 44 cows with frequency 2,62 utilizations the milking robot per day. The milking took averagely 7 minutes and 40 seconds. Milking utilization was 30,70 liters on one cow per day and total milk herd was 1353,01 liters of milk per day.
6

Knowledge discovery and machinelearning for capacity optimizationof Automatic Milking RotarySystem

Xie, Tian January 2016 (has links)
Dairy farming as one part of agriculture has thousands of year’s history. The increasingdemands of dairy products and the rapid development of technology bring dairyfarming tremendous changes. Started by first hand milking, dairy farming goes throughvacuum bucket milking, pipeline milking, and now parlors milking. The automatic andtechnical milking system provided farmer with high-efficiency milking, effective herdmanagement and above all booming income.DeLaval Automatic Milking Rotary (AMRTM) is the world’s leading automatic milkingrotary system. It presents an ultimate combination of technology and machinerywhich brings dairy farming with significant benefits. AMRTM technical milking capacityis 90 cows per hour. However, constrained by farm management, cow’s condition andsystem configuration, the actual capacity is lower than technical value. In this thesis, anoptimization system is designed to analyze and improve AMRTM performance. The researchis focusing on cow behavior and AMRTM robot timeout. Through applying knowledgediscover from database (KDD), building machine learning cow behavior predictionsystem and developing modeling methods for system simulation, the optimizing solutionsare proposed and validated. / Mjölkproduktion är en del av vårt jordbruks tusenåriga historia. Med ökande krav påmejeriprodukter tillsammans med den snabba utvecklingen utav tekniken för det enormaförändringar i mjölkproduktionen. Mjölkproduktion började inledningsvis med handmjölkningsedan har mjölkproduktionsmetoder utvecklats genom olika tekniker och gettoss t.ex. vakuum mjölkning, rörledning mjölkning, fram till dagens mjölkningskarusell.Nu har det automatiska och tekniska mjölkningssystem försedd bönder med högeffektivmjölkning, effektiv djurhållningen och framför allt blomstrande inkomster.DeLaval Automatic Milking Rotary (AMRTM) är världens ledande automatiska roterandemjölkningssystemet. Den presenterar en ultimat kombination av teknik och maskinersom ger mjölkproduktionen betydande fördelar. DeLaval Automatic Milking Rotarytekniska mjölknings kapacitet är 90 kor per timme. Den begränsas utav jordbruksdrift,tillståndet hos kor och hantering av systemet. Det gör att den faktiska kapaciteten blirlägre än den tekniska. I denna avhandling undersöks hur ett optimeringssystem kan analyseraoch förbättra DeLaval Automatic Milking Rotary prestanda genom fokusering påkors beteenden och robot timeout. Genom att tillämpa kunskap från databas (KDD), skapamaskininlärande system som förutsäger kors beteenden samt utveckla modelleringsmetoderför systemsimulering, ges lösningsförslag av optimering samt validering.

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