جستجوی مقالات مرتبط با کلیدواژه "انباره" در نشریات گروه "مکانیک"

Nowadays, due to environmental concerns and the hope of limiting the phenomenon of pollution in mega-cities, the development of electric vehicles is one of the priorities of the modern industrial world. Lithium batteries are the main type of batteries used in electric cars. Temperature is one of the most effective parameters on the performance of these batteries because it can change their chemical behavior. Due to the necessity of battery operation in a suitable temperature range and with uniform temperature distribution, it is necessary to adopt a suitable and optimal cooling method with efficiency and reliability at all three levels of cell, module, and battery pack. One of the passive methods for thermal management in batteries is the use of a heat pipe. The purpose of this research is to use a new arrangement for the heat pipe in a battery module and study its temperature effects with the help of 3D thermal model simulation and an electrochemical model (NTGK) to simulate this system. The results of this study indicate that this new arrangement can improve the temperature uniformity distribution of the battery module by 4.1%.

Pressure fluctuations during fuel injection are one of the factors that negative effect on performance of diesel engine. These fluctuations are caused by the rapid opening and closing of the nozzles and the creation of pressure waves in the fuel rail. One way to control these pressure fluctuations is to change the injector design and use an accumulator in the injector. This study is performed to investigate the effect of adding accumulator on the injector to control pressure waves in the common rail fuel injection system of diesel engines. As the simulation results show, at injection pressure of 1000 bar and energizing time of 0.8 milliseconds, in the case of no accumulator, the maximum pressure fluctuation in the fuel rail is 1046 bar and the minimum pressure is 891 bar. By adding an accumulator with a volume of 4 cm3, the maximum pressure continued to decrease and reached 1023 bar, and the minimum pressure of the fuel rail increased by 17 bar, 943 bar. These changes are also noticeable in other pressures and energizing times, so the best accumulator that has the most impact on reducing pressure fluctuations is the accumulator with a volume of 4 cm3.

Exhaust system is one of the most important parts of the engine، in which two major parameters including back pressure and noise are considered in the design. The goal of the present work is to simulate and validate the noise and the exhaust gas flow of a three-liter turbo-charged diesel engine with the maximum power of 98 kW by the FLUENT software. Afterwards، the pipe diameter of the exhaust system was optimized in order to maximize the engine power by the GT-POWER software. As the increase of the engine power caused the rise of the exhaust gas noise، the optimum shape of the exhaust muffler was represented. Results showed that 1% increase in the predicted engine power by optimizing the size of the exhaust pipe system. In addition، the proposed muffler with the elliptical enclosure and un-aligned inlet and outlet pipes had minimum back pressure and outlet noise.