Gaz türbini kanatları kanallarında soğutma performansının araştırılması

Türbin kanatlarının soğutulması farklı bölgelerinde farklı soğutma teknikleri kullanarak yapılmaktadır. Kompresörde üretilen havanın yaklaşık %20’si soğutma sistemlerinde kullanılmaktadır. Kanat içine gönderilen bu hava önce iç kanallardan daha sonrada kanat dış profili üzerinden ve kanat uç kısmından dışarıya atılarak soğutma gerçekleştirilir. Bu soğutma tekniklerinin iç soğutma ve yüzeyde hava filmi meydana getirme ve çarpmalı jetle soğutma teknikleri uygulanmaktadır. Kanatta iç soğutma yapılması için bazen U şeklinde soğutma kanalları kullanılmaktadır. Bu kanallarda çeşitli açılarda kanatçıklar (ripler) kullanılarak soğutma performansları arttırılmaya çalışılmaktadır. Bu çalışmada U şeklindeki 180° dönüşlü düz bir kanalın ve alt ve üst yüzeylerine 90° ve 45° yerleştirilen kanatçıkların yerleştirildiği kanallardaki soğutma performansına etkisi 3 farklı Reynolds sayısı (22000, 27500 ve 33000) için deneysel olarak sıvı kristal termografisi metoduyla kanal yüzeyindeki ısı geçiş katsayısı ve Nu sayısının değişimi araştırılmıştır. Elde edilen sonuçlar jet geometrisinin etkisi, Reynolds sayısının etkisi, kanal içindeki hız dağılımı ve ısı geçiş katsayısı dağılımları gösterilmiştir.

Investigation of cooling performances at the gas turbine blade channel

The cooling of the turbine blades in different parts of the turbine is carried out using different cooling techniques. Approximately 20% of the air produced in compressors is used in cooling systems. The air is sent into the wing through the internal channels. It travels through the outer profile of the wing and is vented through the far edge of the wing. The cooling process is then completed. Among the applied cooling techniques are internal cooling, surface air film forming, and jet impingement cooling techniques. Sometimes U-shaped cooling channels are utilized for internal cooling to take place in the wing. An attempt to increase the cooling performance has been made with the utilization of wings (rips) at various angles. The change in the Nu number and the heat transfer coefficient on the channel surface as well as the impact of positioning 90° and 45° blades on a U-shaped 180° smooth (straight) channel on the cooling performance for three different Reynolds numbers (22000, 27500 and 33000) has been investigated experimentally using the method of liquid crystal thermography. The effect of the jet geometry, impact of the Reynolds number, velocity distribution within channels, and the heat transfer coefficient distributions are shown in the results.

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Havacılık ve Uzay Teknolojileri Dergisi-Cover
  • ISSN: 1304-0448
  • Yayın Aralığı: Yılda 2 Sayı
  • Başlangıç: 2003
  • Yayıncı: Dr. Öğr. Üyesi Fatma Kutlu Gündoğdu