Michael von SPAKOVSKY, Kehinde ALABI, David MOORHOUSE, Jose CAMBEROS, Foluso LADEINDE

The use of the 2nd law as a potential design tool for aircraft air frame subsytems

Bu çalışmada entegre uçak tasarım/sentezinin bir bileşeni olarak havayla etkileşim altsisteminin tersinmez termodinamik modellemesi sunulmaktadır. Karmaşık geometrilerde entropi hesaplama yöntemleri eğrilerden meydana gelen kordinatlarda türbülans etkilerini de içerecek şekilde anlatılmıştır.Hem viskoz olmayan hem de viskoz hesapları rapor edilmiş ve entropi denklemindeki çeşitli terimlerin katkıları araştırılmıştır.Yöntemin geçerliliği doğrulanmış ve sonra B747-200 uçağı üzerindeki akış ile ilgili entropi üretimi hesabına kadar genişletilmiştir.Sonuçlar entropi üretiminin çoğunun türbülanstan dolayı olduğunu göstermiştir.Entropi denklemindeki viskoz ısı üretimi terimi ısı transferi terimine göre daha büyüktür. Sonuçların tasarımın geliştirilmesine olan katkıları kısaca anlatılmıştır.

Uçakların havayla etkileşim altsistemi için potansiyel bir tasarım aracı olarak ikinci kanunun kullanımı

This paper presents the modeling of the irreversible thermodynamics of the Air Frame Subsystem as a component of integrated aircraft design/synthesis. Entropy calculation procedures for complicated geometries in curvilinear coordinates are described, including the effects of turbulence. Both inviscid and viscous calculations are reported and the contributions of the various terms in the entropy equation are investigated. The procedure is validated and then extended to the calculation of entropy generation associated with flow over the B747-200 aircraft. Results show that most of the entropy generation is due to turbulence. The viscous dissipation term in the entropy equation dominates compared to the heat transfer term. The implications of the results for design improvement are briefly discussed.

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