The thesis is focused on possibilities of asynchronous motors cooling with use of simulation at ANSYS Workbench program. It is divided into two parts. The first part deals with analyses of cooling medium circulation through ventilator and cooling medium circulation on the motor surface. As a result of the analyses is air speed distribution and air pressure representation. The second part of the thesis includes simulation of motor temperature rise both with cooling and without cooling at Ansys Workbench application together with temperature measurement of real asynchronous motor in the laboratory. For cooling purposes air circulation was used. The goal of my research is comparison of the computing results with the measured results.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-11-13T12:25:17Z No. of bitstreams: 1 Jonatan Silva da Silva_.pdf: 2236357 bytes, checksum: f3eae6a5cb0b0488ccdd0eaa3d372692 (MD5) / Made available in DSpace on 2017-11-13T12:25:17Z (GMT). No. of bitstreams: 1 Jonatan Silva da Silva_.pdf: 2236357 bytes, checksum: f3eae6a5cb0b0488ccdd0eaa3d372692 (MD5) Previous issue date: 2017-07-17 / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / Com o avanço da tecnologia, os circuitos eletrônicos são fabricados em tamanhos cada vez menores e com maior potência de processamento de dados. Atualmente os chips estão sendo produzidos em pequenas áreas, com mais de 1010 transistores encapsulados, o que causa aumento de calor gerado e assim elevação da temperatura de operação. A elevada temperatura é responsável pelo aumento de falhas e ocasiona a diminuição da eficiência dos mesmos. As falhas mais frequentes causadas pelo aquecimento dos circuitos integrados são o aumento do estresse mecânico nas juntas de solda, que podem quebrar ou romper contatos por fadiga térmica; incompatibilidade de expansão térmica dos diferentes materiais; a modificação do desempenho elétrico do dispositivo; o aumento de correntes de fuga, a aceleração do processo de corrosão e a ocorrência de eletro migração. Devido a isso, o presente trabalho apresenta uma análise experimental de um sistema de microcanais com escoamento de fluido monofásico, água, para a dissipação de calor e, portanto, a diminuição da temperatura de um sistema, que representa uma placa de circuito com componentes eletrônicos. Os microcanais foram desenvolvidos em uma fita adesiva e termocondutiva dupla face com uso de uma impressora de corte. O dispositivo mede 50 x 70 mm e possui 10 microcanais paralelos de seção retangular com 800 µm de largura e 400 µm de altura, resultando em um diâmetro hidráulico do canal de escoamento de 533 µm. Testes são realizados para diferentes fluxos de calor e vazões de líquido. Os resultados demonstraram que houve diminuição das temperaturas da parede comparando as velocidades mássicas, obtendo-se uma variação média de 10,2 °C quando modificado a velocidade mássica de 51,2 kg/m²s para 102,4 kg/m²s, onde o fluido refrigerante apresentou uma redução de 27,5 °C. / With the advancement of technology, electronic circuits are manufactured in ever smaller sizes and with greater data processing power. Currently chips are being produced in small areas, with more than 1010 encapsulated transistors, which causes increased heat generated and thus elevated operating temperature. The high temperature is responsible for the increase of faults and causes the decrease of their efficiency. The most frequent faults caused by the heating of the integrated circuits are the increase of the mechanical stress in the joints of weld, that can break or break contacts by thermal fatigue; Incompatibility of thermal expansion of different materials; Modifying the electrical performance of the device; The increase of leakage currents, the acceleration of the corrosion process and the occurrence of electro migration. Due to this, the present work presents an experimental analysis of a system of microchannels with single phase fluid flow, water, for the dissipation of heat and, therefore, the decrease of the temperature of a system, representing a circuit board with electronic transistors. The microchannels were developed in a double-sided thermo-conductive adhesive tape using a cut-off printer. The device measures 50 x 70 mm and has 10 parallel microchannels of rectangular section with 800 μm wide and 400 μm in height, resulting in a hydraulic flow channel diameter of 533 μm. Tests are performed for different heat flows and liquid flows. The results showed that there was a decrease of the wall temperatures comparing the mass velocities, obtaining a mean variation of 10.2 ° C when modified at a mass speed of 51.2 kg / m² to 102.4 kg / m², where the refrigerant showed a reduction of 27,5 °C.

An experimental and numerical investigation has been conducted to examine steady, internal, nozzle-generated, gas/liquid mist cooling in vertical channels with ultra-thin, evaporating subcooled liquid films. Interest in this research has been motivated by the need for a highly efficient cooling mechanism in high-power lasers for inertial fusion reactor applications. The aim is to quantify the effects of various operating and design parameters, viz. liquid atomization nozzle design (i.e. spray geometry, droplet size distribution, etc.), heat flux, liquid mass fraction, film thickness, carrier gas velocity, temperature, and humidity, injected liquid temperature, gas/liquid combinations, channel geometry, length, and wettability, and flow direction, on mist cooling effectiveness. A fully-instrumented experimental test facility has been designed and constructed. The facility includes three cylindrical and two rectangular electrically-heated test sections with different unheated entry lengths. Water is used as the mist liquid with air, or helium, as the carrier gas. Three types of mist generating nozzles with significantly different spray characteristics are used. Numerous experiments have been conducted; local heat transfer coefficients along the channels are obtained for a wide range of operating conditions. The data indicate that mist cooling can increase the heat transfer coefficient by more than an order of magnitude compared to forced convection using only the carrier gas. The data obtained in this investigation will allow designers of mist-cooled high heat flux engineering systems to predict their performance over a wide range of design and operating parameters. Comparison has been made between the data and predictions of a modified version of the KIVA-3V code, a mechanistic, three-dimensional computer program for internal, transient, dispersed two-phase flow applications. Good agreement has been obtained for downward mist flow at moderate heat fluxes; at high heat fluxes, the code underpredicts the local heat transfer coefficients and does not predict the onset of film rupture. For upward mist flow, the code underpredicts the local heat transfer coefficients and, contrary to experimental observations, predicts early dryout at the test section exit.