Abstract
In this study, spoilers were installed on the lobed nozzle principal model. Keeping axial position unchanged, the different widths of spoilers were mounted along the circumferential direction of a mixer tube. The effects of spoilers on the jet mixing of lobed nozzle were investigated by numerical method, and the results showed that, before or after the installation, the flow ratio did not change significantly. The value of thermal mixing efficiency and total pressure recovery coefficient had a corresponding improvement. The spoilers increased the borderline area of the primary and secondary streams, thus the mixing was accelerated. Spoilers can avoid high-temperature primary stream impinging the wall of the tube, and the temperature of mixing tube wall decreased significantly.
Highlights
Because of the especial shape, lobed nozzles can mix the primary and secondary streams with high effectiveness and induce lower pressure loss (Shumpert 1980)
Investigations concluded that the increase in the interfacial area between the primary and secondary streams (Elliott et al 1992) — at the same time forming inviscid streamwise vortices at the wake (Povinelli and Anderson 1984) — and the streamwise vortices interacting with the normal vortices ring which are formed at the interface of the streams for the gradient of the axial velocity (McCormick and Bennett 1994), are the dominating factors for high mixing effectiveness
Spoilers with different widths were mounted on the lobed nozzle
Summary
Because of the especial shape, lobed nozzles can mix the primary and secondary streams with high effectiveness and induce lower pressure loss (Shumpert 1980). 460 Dawei L, Jun H, Zhiqiang S, Jinzu J induce new streamwise vortices, transform the distribution of the primary stream, accelerate the mixing in the region off the lobe peaks which can be effectively utilized to lower the temperature of the mixing stream near the duct This has a dual effect on the suppression of the infrared radiation of the plume and wall (Sheng et al 2015b). In order to simulate the downwash, the secondary flow was set to velocity inlet, which is 25 m∙s–1. The same numerical simulation of jet mixing of lobed nozzle with the Fluent software packages has been used and validated in previous studies (Sheng et al 2014; Sheng et al 2015a; Sheng et al 2015b; Liu et al 2015). Manag., São José dos Camp2os, Vol., No 4, pp.4592-466, Oct.-Dec., 2016
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