R ehabilitation of hydraulic turbines of existing po- wer plants is an important topic because of... more R ehabilitation of hydraulic turbines of existing po- wer plants is an important topic because of the low performance, poor reliability, frequent maintenance intervals and undesirable cavitation properties of old turbines at the plants. Rehabilitation projects increased worldwide to improve turbine designs and to reach the desired performance characteristics, especially with the improvements in computational power and Computational Fluid Dynamics (CFD) technology. However, rehabilitation of old power plants is often more difficult than the design of the turbines for new power plants since most of the existing parts cannot be altered because some of the parts are buried and the space is limited with the size of the old turbine. Both experimental and numerical methods are common in the design [1] and rehabilitation of Francis turbines. Performing numerical simulations is an efficient approach as an alternative to model tests. Steady state and transient Francis turbine simulation results are presented in the study of Beatove et al. [2]. Interactions
Francis type hydraulic turbine runners have complex blade shapes. Runner blades have three dimens... more Francis type hydraulic turbine runners have complex blade shapes. Runner blades have three dimensional profiles that direct the incoming flow. In this study, a reverse engineering methodology is developed for the redesign of turbines. Traditional reverse engineering steps are combined with the basics and flow dynamics of hydraulic turbines and applied to two different turbine runners (which have different specific speeds) of two different hydroelectric power plants in operation. The methodology is first verified by application on the first runner and utilized for the redesign of the runner of another power plant. The reasons for the reduced performance of the second runner are examined with the help of the new inverse engineering design methodology and a rehabilitation study is performed. Thus, the runner which only provides 70% of its installed capacity, is redesigned and can now utilize its full capacity. Francis tipi su türbinlerine ait çark kanatlarının yapısı oldukça karmaşıktır. Üç boyutlu profilleri ile gelen akışı yönlendirirler. Bu çalışmada, türbinlerin yeniden tasarımı için bir tersine mühendislik yöntemi geliştirilmiştir. Geleneksel tersine mühendislik yöntemi, hidrolik türbin temel çalışma prensipleri ve akışkanlar mekaniği temelleri ile birleştirilerek iki farklı kullanımda olan santralin türbin çarkına (iki farklı özgül hızı olan) uygulanmıştır. Yöntem, öncelikle bir santrale uygulanarak doğrulanmış, ardından diğer santralin türbin çarkının yeniden tasarımında kullanılmıştır. İkinci santralin türbin çarkının çalışmasındaki sorunların sebepleri yeni geliştirilen yöntem ile araştırılmış ve çarkın rehabilitasyonu gerçekleştirilmiştir. Kapasitesinin %70'i verimle çalışan çark, tam kapasite çalışır hale gelmiştir.
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