Описание: In experiments on aprototypical combustor, Richard Steinert identifies new insights on the impactof noise on the phenomenon known as thermoacoustic instability.
Автор: Vivekanandan Jegadeesan und Raman I. Sujith Название: Noise Induced Transition In Thermoacoustic System ISBN: 3659159581 ISBN-13(EAN): 9783659159589 Издательство: LAP LAMBERT Academic Publishing Рейтинг: Цена: 9894 р. Наличие на складе: Нет в наличии.
Описание: Thermoacoustic instability is one of the major obstacle in the development and operation of high performance combustors. Extensive research has been performed to predict the onset instability, assuming that the processes that occur in the combustion chamber are deterministic in nature. But in a real practical combustion system they are noisy. We investigate the effect of random fluctuations on the stability limits of a combustion system. We add noise through an external source and observe the effect of noise on the system, when it is operating in a bistable region. We observed that noise drastically affects the stability limits of the combustion system. The phenomenon of noise induced transition is observed to play vital role in destabilizing the system
Описание: Thermoacoustic systems with no stacks or intermittent stacks represent a promising alternative to conventional stack-based systems. There is theoretical and experimental evidence that such systems can perform more efficiently and produce more acoustic power than thermoacoustic systems with an array of flat plates or regular pores. As opposed to conventional thermoacoustic systems, no-stack setups do not include porous material as a medium for storing and transferring heat. In such systems, heat is transported by gas parcels directly between heat exchangers. A simplified Lagrangian model has been developed in this work to approximately analyze no-stack standing-wave thermoacoustic configurations. More accurate simulations of favorable configurations are investigated with the help of computational fluid dynamics (CFD). Using CFD code FLUENT, more efficient setups were found with the second law efficiency up to 55%. The dependence of system performance is reported for a range of system parameters. A good agreement between the simplified model and CFD results was achieved in most cases.
Описание: The thermoacoustic engine is a device that converts heat energy into sound or acoustic power. They are used currently to recover waste heat from military vehicles and converting it to electricity, which means that such devices can play a significant role in power generation for domestic & commercial purposes. This study demonstrates an attempt to design a 1-meter-long thermoacoustic heat engine with optimum efficiency. This will be done using DeltaEC, a software which was developed especially for the modeling of low amplitude thermoacoustic devices. The optimization process includes geometrical parameters of the resonator tube and the stack, the working fluid, and the heat input to the engine. The present optimization process has shown that slab stacks made of Celcor (a Ceramic material) demonstrated much better performance than other stack shapes and materials. For a 1.1239-meter-long and 0.011 m2 square-shaped resonator tube, a 7.75 cm long slab stack made of Celcor having 0.304 mm-thick-plates, spaced by 0.648 mm, giving a porosity ratio of 0.68067, will theoretically convert heat to acoustic power at an efficiency of 30.611% which is equivalent to 47.97% of Carnot’s efficiency.
Автор: Gregory W. Swift Название: Thermoacoustics ISBN: 331966932X ISBN-13(EAN): 9783319669328 Издательство: Springer Рейтинг: Цена: 12621 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание: At the same time, it remains firmly grounded in experimental results, basing its discussions on the distillation of a body of experiments spanning several decades and countries. The book begins with detailed treatment of the fundamental physical laws that underlie thermoacoustics.
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