Isothermal modeling of aerodynamic structure of the swirling flow in a two-stage burner

The work deals with the experimental study of the aerodynamic structure of a swirling flow in the isothermal model of two-stage vortex combustion chamber. The main attention is focused on the process of flow mixing of two successively connected tangential swirlers of the first and second stages of the working section. Data on flow visualization are presented for two patterns of flow swirling. Time-averaged profiles of the axial and tangential velocity components are obtained with the help of laser-Doppler anemometer. In the case of flow co-swirling between two stages of the working section, instability of a secondary flow in the form of precessing vortex was distinguished. For the regime with counter flow swirling, effective mixing of the swirl flows was found; this was reflected by formation of the flow with uniform distribution of axial velocity over the cross-section

Isothermal modeling of aerodynamic structure of the swirling flow in a two-stage burner

The work deals with the experimental study of the aerodynamic structure of a swirling flow in the isothermal model of two-stage vortex combustion chamber. The main attention is focused on the process of flow mixing of two successively connected tangential swirlers of the first and second stages of the working section. Data on flow visualization are presented for two patterns of flow swirling. Time-averaged profiles of the axial and tangential velocity components are obtained with the help of laser-Doppler anemometer. In the case of flow co-swirling between two stages of the working section, instability of a secondary flow in the form of precessing vortex was distinguished. For the regime with counter flow swirling, effective mixing of the swirl flows was found; this was reflected by formation of the flow with uniform distribution of axial velocity over the cross-section

Isothermal modeling of aerodynamic structure of the swirling flow in a two-stage burner

The work deals with the experimental study of the aerodynamic structure of a swirling flow in the isothermal model of two-stage vortex combustion chamber. The main attention is focused on the process of flow mixing of two successively connected tangential swirlers of the first and second stages of the working section. Data on flow visualization are presented for two patterns of flow swirling. Time-averaged profiles of the axial and tangential velocity components are obtained with the help of laser-Doppler anemometer. In the case of flow co-swirling between two stages of the working section, instability of a secondary flow in the form of precessing vortex was distinguished. For the regime with counter flow swirling, effective mixing of the swirl flows was found; this was reflected by formation of the flow with uniform distribution of axial velocity over the cross-section

Isothermal modeling of swirling flow aerodynamic structure in a two-stage burner

The work motivation is determined by the extensive use of interacting swirling flows in counter vortex quenchers and vortex combustion chambers. To optimize the design of such devices, it is necessary to understand the structure of the flow and the mechanisms of interaction of c

Isothermal modeling of swirling flow aerodynamic structure in a two-stage burner

Актуальность работы обусловлена широким использованием взаимодействующих закрученных потоков в устройствах для гашения энергии и в вихревых камерах сгорания. Чтобы оптимизировать конструкцию таких устройств, необходимо понимание структуры течения и механизмов взаимодействия соосных закрученных потоков. Применительно к горелочным устройствам данные исследования необходимы для наиболее эффективного сжигания топлива, уменьшения загрязняющих выбросов продуктов сгорания и увеличения эксплуатационного срока службы камер сгорания. Цель работы: экспериментальное исследование аэродинамической структуры закрученного течения в изотермической модели двухступенчатой вихревой камеры сгорания. Основное внимание уделено процессу смешения потоков двух последовательно соединённых тангенциальных завихрителей первой и второй ступеней рабочего участка. Методы исследования: визуализация течения с использованием цифровой высокоскоростной камеры для исследования различных режимов работы вихревого горелочного устройства и лазерно-доплеровская анемометрия для получения профилей осреднённых по времени осевой и тангенциальной компонент скорости, а также их пульсационных составляющих (среднеквадратичные отклонения). Результаты. В случае режима с созакруткой потоков между двумя ступенями рабочего участка было выявлено образование вторичной неустойчивости течения в виде прецессирующего вихря. При режиме с противокруткой обнаружено эффективное смешение закрученных потоков. Исходя из результатов проведенных изотермических опытов можно заключить, что вариант с противокруткой является более предпочтительным для использования в двухступенчатой горелке в плане возможности более быстрого смешения горелочных струй первой и второй ступеней. Результирующее течение характеризуется более равномерным заполнением внутреннего объема устройства в сочетании с устойчивой выраженной закруткой потока, которая должна увеличивать время пребывания частиц топлива в зоне активного горения и, соответственно, полноту его выгорания. Последний фактор достигается без развития сильной гидродинамической неустойчивости течения, характерной для аппаратов с сильной закруткой потока.The work motivation is determined by the extensive use of interacting swirling flows in counter vortex quenchers and vortex combustion chambers. To optimize the design of such devices, it is necessary to understand the structure of the flow and the mechanisms of interaction of co<axial swirling flows. With regard to burner devices, these studies are important for the most efficient combustion of fuel, reducing the polluting emissions of combustion products and increasing the durability of combustion chambers. The main aim of the study is the experimental investigation of aerodynamic structure of the swirling flow in isothermal model of two-stage vortex burner device. The main attention is paid to the mixing process of swirling streams formed in two consecutively connected tangential swirlers representing first and second stages of the burner device. The methods used in the study. Flow visualization for various swirl flow configurations were obtained using a digital high-speed camera. Profiles of the time-averaged axial and tangential velocity components as well as their pulsating parts (root mean square deviation) were obtained using a laser-Doppler anemometer. The results. The formation of a secondary instability of the flow in the form of a precessing vortex was revealed in the case of regime with co-swirl of flows between two stages of the working section. Effective mixing of swirl flows was detected in the counter-swirl mode. Based on the results of conducted isothermal experiments it can be concluded that the counter-swirl mode is more preferable for application in a two-stage burner in terms of the possibility of faster mixing of the burner flows of the first and second stages. The resulting flow is characterized by a more uniform flow distribution inside the device in combination with a stable flow swirling, which shouldincrease the residence time of the fuel particles in the active combustion zone and, accordingly, ensures their complete burn-out. The latter factor is achieved without the development of a strong hydrodynamic instability of the flow, which is characteristic of apparatuswith a strong flow swirling