High pressure droplet burning experiments in reduced gravity
32nd Joint Propulsion Conference and Exhibit, 1996, Florida, Amerika Birleşik Devletleri, 1 - 03 Temmuz 1996, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Florida
- Basıldığı Ülke: Amerika Birleşik Devletleri
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
High pressure droplet burning characteristics of five fuels are investigated under normal and reduced gravity conditions. The reduced gravity experiments have been conducted by using the parabolic flights of the CNES Caravelle and the NASA KC-135 aircraft. A fully automatic high pressure droplet gasification facility has been developed for these experiments. High speed camera is used to determine the time histories of burning droplets, from which average droplet burning rates are determined. For all experiments, the suspended droplet technique is used. Initial droplet diameters are about 1.5 mm. Subcritical and supercritical droplet burning regimes are explored. The experimental results for all fuels show that the droplet burning lifetime decreases strongly with increasing pressure in the subcritical regime. When the pressure is increased above the critical pressure of the pure liquid, the droplet burning lifetimes remain constant in the average. Therefore, the minimum burning time observed in the literature is not confirmed here. In order to take into account the residual gravity enhanced natural convection effects, a correction based on the Grashof number is applied. This correction allows a comparison of various experiments under different gravity and pressure conditions and an estimate of the burning time without any convection effect. In the subcritical regime, this burning time varies as p.-0.37