Design, fabrication and high velocity oxy-fuel torch tests of a Cf-ZrB2- fiber nozzle to evaluate its potential in rocket motors. (5th November 2016)

• Record Type: Journal Article
• Authors: Sciti, D.; Zoli, L.; Silvestroni, L.; Cecere, A.; Di Martino, G.D.; Savino, R.
• Is Part Of: Materials & design. Volume 109(2016)
• Page Start: 709
• Page End: 717
• Publication Date: 2016-11-05
• Subjects: ZrB2 -- Carbon fibers -- Oxidation -- Ablation -- Nozzle; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.07.090
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: The resistance to ablation of a ceramic nozzle made of a 50 vol% Carbon fiber-50 vol% ZrB2 composite was evaluated in a high velocity oxy-fuel torch (HVOF) in conditions simulating typical exhaust engine flows. The composite was prepared by hot pressing a mixture of ZrB2 powders and C chopped fibers and characterized in terms of microstructural features, strength and toughness. Then, the sintered pellet was machined by electro-discharge machining to obtain a ceramic throat. The throat was assembled to convergent and divergent graphite parts to compose a segmented nozzle and tested in HVOF torch under a heat flux of 2.5 MW/m 2 and flame temperature of 2730 K. Fluid dynamic simulations enabled to rebuild the heat field temperatures of the jet flow and of the solid nozzle. The throat well survived 30 s undergoing little oxidation of the frontal zone without dimension or shape variation. No appreciable ablation of the throat was measured. Graphical abstract: Highlights: A segmented nozzle composed of divergent and convergent graphite parts and of a ceramic throat was designed. The ceramic throat with composition 50 vol% Carbon fiber - 50 vol% ZrB2 was machined by EDM from a sintered pellet. The nozzle was tested in a high velocity oxy-fuel torch (HVOF) in conditions simulating typical exhaust engine flows. No appreciable erosion of the throat was observed after test at 2.5 Mach supersonic flow and 2730 K flame temperature.