Оценка теплогидравлической эффективности профилирования оребренных поверхностей судовых утилизационных котлов
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Дата
2018
Автори
Кузнецов, В. В.
Кузнецов, Г. В.
Kuznetsov, V. V.
Kuznetsov, H. V.
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Анотація
Утилизация теплоты отработавших газов главных судовых малооборотных дизельных двигателей является действенным способом повышения эффективности судовой энергетической установки в целом. Повышение тепловой эффективности главных дизельных двигателей и соответствующее снижение температуры их отработавших газов вызывают необходимость обоснования способов интенсификации процессов теплоотдачи в утилизационных котлах для снижения их массогабаритных показателей. Зассмотрен один из способов интенсификации процессов теплоотдачи путем нанесения системы лунок на ребра. Методом математического моделирования произведена оценка теплогидравлической эффективности предложенной теплообменной поверхности. Получено, что нанесение лунок на ребра может улучшить эффективность теплоотдачи до 30 %.
Diesel plants with direct power transmission to the propeller occupy a leading position as the main ship power plants. This is due to the constantly increasing efficiency of low-speed diesel engines, which today is about 50 %. This led to decrease of the exhaust gas temperature to 230 ... 260 °C and decrease in losses from 35 ... 40 to about 25 %. However, such a percentage of losses remains is highest in the structure of the heat balance of the ship’s power plant, so the leading global manufacturers of main diesel engines are constantly working to reduce it. The utilization of the main ship low-speed diesel engines exhaust gases heat is an effective way to increase the efficiency of the ship’s power plant as a whole. Improving the thermal efficiency of main diesel engines and a corresponding decrease of the temperature of their exhaust gases necessitates substantiation of ways to intensify heat transfer processes in waste heat boilers in order to reduce their weight and size indexes. The article describes one of the ways of intensify heat transfer processes by applying a system of dimples on the fins. The method of mathematical modeling has been used to estimate the thermal and hydraulic efficiency of the proposed heat exchange surface. It was found that the application of dimples on the fins can improve the heat transfer efficiency up to 30 %.
Diesel plants with direct power transmission to the propeller occupy a leading position as the main ship power plants. This is due to the constantly increasing efficiency of low-speed diesel engines, which today is about 50 %. This led to decrease of the exhaust gas temperature to 230 ... 260 °C and decrease in losses from 35 ... 40 to about 25 %. However, such a percentage of losses remains is highest in the structure of the heat balance of the ship’s power plant, so the leading global manufacturers of main diesel engines are constantly working to reduce it. The utilization of the main ship low-speed diesel engines exhaust gases heat is an effective way to increase the efficiency of the ship’s power plant as a whole. Improving the thermal efficiency of main diesel engines and a corresponding decrease of the temperature of their exhaust gases necessitates substantiation of ways to intensify heat transfer processes in waste heat boilers in order to reduce their weight and size indexes. The article describes one of the ways of intensify heat transfer processes by applying a system of dimples on the fins. The method of mathematical modeling has been used to estimate the thermal and hydraulic efficiency of the proposed heat exchange surface. It was found that the application of dimples on the fins can improve the heat transfer efficiency up to 30 %.
Опис
Кузнецов, В. В. Оценка теплогидравлической эффективности профилирования оребренных поверхностей судовых утилизационных котлов = Estimation of thermal and hydraulic efficiency profiling of fibbed marine waste heat boiler’s surfaces / В. В. Кузнецов, Г. В. Кузнецов // Shipbuilding & Marine Infrastructure. – 2018. – № 2 (10). – C. 245–251.
Ключові слова
судно, утилизационный котел, теплообменная поверхность, профилирование, лунка, vessel, waste heat boiler, heat exchange surface, profiling, dimple