Вдосконалення робочого процесу гідротурбін та систем їх регулювання

The paper provides the detail analysis of the causes of various types of the vortex motion of the turbulent flow in the inlet parts of the turbine and in the inter-blade channels of the runner. The causes of the appearance of large-scale vortex structures in the meridional sections of the spiral case of radial-axial hydraulic turbines with the heads of 400–500 m are shown. As a result of this phenomenon, in the section of the spiral case the flow is directed in the region of the walls to the runner. In the central part it is directed from the runner, i. e. the spiral case executing its functions of supplying the flow functions only with part of its section – the near-wall zone – where the vortex near-wall flow with increased velocity and energy losses enters to the channels of the runner. These conclusions in the work are argued by extensive experimental data. Energy losses in the spiral case reaches 3–5 % and a complex vortex structure, which enters to the runner, leads to a decrease of the energy characteristics. The flow inlet to the runner using nozzle devices located on the ring in front of the runner is considered in the paper. These nozzle devices increase the velocity by five or more times and provide low losses in the inlet (about 0,5 %) and almost uniform flow in front of the runner with a moment of quantity of motion, which provides an optimal operation of the hydraulic turbine. The improvement of the working flow and control systems is presented in this paper using new design solutions, for which more than ten patents of Ukraine for the invention were obtained. In particular, as a result of this study of the working processes of Francis-Deriaz hydraulic turbines, which allowed the use of blade turbines for the heads of more than 400–500 m up to 800–1000 m with high energy and cavitation characteristics with wide operating areas in terms of rates (powers) and heads, with an increase of 2–7 % average operating efficiency. The working process of a new type of diagonal-axial hydraulic turbine with a very wide operation range in terms of flow and pressure with a significantly increased average operating efficiency, increased operation reliability, which is illustrated by the predictive universal characteristic, is also considered. This characteristic allows the use of rotary-blade hydraulic turbines for heads up to 230–250 m. Therefore, the carried out improvement of the working process of hydraulic turbines and their control systems convincingly proves the advantage of the new scientific and technical solutions in comparison with previously used ones.В роботі проведено детальний аналіз причин виникнення різних видів завихреності турбулентного потоку в підвідних органах гідротурбіни і в міжлопатевих каналах робочого колеса. Показано причини виникнення великомасштабних вихрових структур в меридіональних перетинах спіральних камер радіально-осьових гідротурбін на напори 400–500 м. Внаслідок цього явища в перерізі спіральної камери потік спрямований в області стінок до робочого колеса, а в центральній частині від робочого колеса, тобто спіральна камера виконуючи свої функції підведення потоку функціонує лише частиною перетину – пристіночної зони, в якій завихрений пристінковий потік зі збільшеною швидкістю і втратами енергії надходить в канали робочого колеса. Ці висновки в роботі аргументовані чисельними експериментальними даними. Втрати енергії в спіральній камері досягають 3–5 % і складна вихрова структура, що надходить в робоче колесо приводить до зниження енергетичних показників. В роботі розглядається підвід потоку до робочого колеса за допомогою розташованих по кільцю перед робочим колесом соплових апаратів, що збільшують швидкість в п'ять і більше разів і забезпечують низькі втрати в підвідних органах (близько 0,5 %) практично рівномірний потік перед робочим колесом з моментом кількості руху, що забезпечує оптимальну роботу гідротурбіни. Удосконалення робочого процесу і систем регулювання представлено в цій роботі з використанням нових конструктивних рішень, на які отримані більш десяти патентів України на винахід. У тому числі в результаті дослідження робочих процесів радіально-діагональних гідротурбін, що дозволили застосовувати лопатеві турбіни на напори понад 400–500 м аж до 800–1000 м з високими енергокавітаційними показниками з широкими зонами експлуатації по витратам (потужностям) і напору, зі збільшеним на 2–7 % середньоексплуатаційним ККД. Розглянуто також робочий процес нового типу діагонально-осьової гідротурбіни з досить широким діапазоном експлуатації по витратам та напору з істотно підвищеним середньоексплуатаційним ККД, підвищеною надійністю експлуатації, що ілюструється прогнозною універсальною характеристикою, що дозволяє застосувати поворотно-лопатеві гідротурбіни на напори до 230–250 м. Таким чином, проведене вдосконалення робочого процесу гідротурбін і систем їх регулювання переконливо доводить перевагу нових науково-технічних рішень в порівнянні з раніше застосовуваними

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