A computational study of two-dimensional serpentine nozzle performance with different annular mixer configurations

Abdelmotalib, Hamada; Lee, Chang-Wook; Seo, Yechan; Lee, Jeekeun

doi:10.1016/j.ijmecsci.2021.106690

Cited by 7 publications

(3 citation statements)

References 32 publications

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“…Firstly, there is no consensus on the evaluation criteria for casing ejectors, which requires further exploration and discussion. Secondly, existing studies on ejector performance mainly focus on the infrared suppressor [29][30][31] at the outlet of the power device, with relatively limited research on the optimization of ejectors coupled with casing structures. Therefore, in future research, it is necessary to address these issues to promote the development of the engine casing field.…”

Section: Introductionmentioning

confidence: 99%

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

Shi,

Wang,

Xiao

et al. 2024

Brodogradnja

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To attain high-performance ejector configurations, an ejection characteristic testing system was established initially to validate the reliability of the Realizable k-ε turbulent model. Subsequently, optimization investigations were conducted on lobed nozzle ejectors with various structural parameters. The effects of four key structural parameters, including lobed nozzle expansion angle α, lobed nozzle width d, number of lobes in the nozzle n, and height of the square-to-circle section h, were systematically studied. Furthermore, the CRITIC method was employed for multi-objective evaluation to identify the optimal design configuration for the casing ejector. The research findings revealed that among the structural parameters, the lobed nozzle expansion angle α exerted the greatest influence on the ejection coefficient and pressure loss coefficient. The weights of the evaluation criteria were determined by the CRITIC method as follows: ejection coefficient (49.38%) < pressure loss coefficient (50.62%). The optimal design configuration determined by the CRITIC method included α = 45°, d = 150 mm, n = 14, and h = 600 mm. The resulting enclosure design ensures smooth airflow within the system, preventing the backflow of high-temperature mainstream fluid and heating the enclosure. It also maintains a temperature distribution in the typical cross-section that meets specified requirements. Additionally, it facilitates improved mixing of mainstream and secondary fluid and reduces exhaust gas temperature.

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Section: Introductionmentioning

confidence: 99%

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

Shi,

Wang,

Xiao

et al. 2024

Brodogradnja

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“…Complex pressure gradients appear in serpentine nozzles that bring different film cooling effects from other structures [15,16]. Abdelmotalib et al [17], Shan et al [18], and He et al [19] studied the mechanism of flow through a serpentine nozzle. The results showed that there were transverse pressure gradients, as well as complex vortex structures.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation of Film Cooling under the Effects of Different Adverse Pressure Gradients

Shi,

Hui,

Zhou

et al. 2024

Aerospace

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Film cooling needs to be applied to serpentine nozzles due to an increase in thermal load. Adverse pressure gradients (APGs) near the upper wall of such nozzles hinder the forward flow of the coolant, and they may even induce a recirculation zone that complicates the cooling of the film in serpentine nozzles under different APGs. In this study, the film cooling characteristics of a serpentine nozzle under various APGs are investigated through numerical simulations. The studied pressure gradients include strong, moderate, and weak APGs. The results show that the APG weakened the adhesion of the coolant to the surface, thereby reducing the film cooling effectiveness (FCE) and the convective heat transfer coefficient (CHTC). The stronger the APG, the greater its obstructive effect. However, the recirculation zone induced by the strong APG was composed of the coolant, and it adhered tightly to the wall, thereby significantly strengthening the FCE and CHTC. The CHTC under the moderate APG significantly increased due to the convergence of two jets ejected from different holes. For the four blowing ratios, the area-averaged FCE under the strong APG was 29.8% and 24.5% higher than that under the moderate and weak APGs, while the area-averaged ratios of the CHTC under the moderate APG were 1.6% and 16.7% higher than those under the strong and weak APGs. Therefore, more holes should be arranged on the film in the zones of moderate and weak APGs.

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“…There is an interaction relationship among the design parameters such as the aspect ratio, inlet and outlet area ratio and offset length ratio of the first S-bend nozzle (Shi et al, 2016). The nozzle outlet area is an important parameter, which has a great influence with the change of the vorticity of flow field (Abdelmotalib et al, 2021;Cheng et al, 2019Cheng et al, , 2017, while changing the center offset and the outlet area ratio has little effect on the aerodynamic performance of the nozzle (He et al, 2020).The static pressure on the upper and lower walls of the S-bend nozzle is very different from the axisymmetric nozzle. The flow near the wall will affects the static pressure, and the curved structure of the S-bend nozzle has a great influence on the state of the jet (Hui et al,2021).…”

Section: Introductionmentioning

confidence: 99%

Research on jet noise characteristics of aeroengine double S-bend nozzles with different cross sections

Shao

Zheng

et al. 2022

HFF

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Purpose This study aims to improve the survivability and maneuverability of the fighter,and study the stealth performance of fighter in the jet noise of aeroengine, it is of great significance to study the jet noise characteristics of double S-bend nozzles. Design/methodology/approach The multiparameter coupling and super-ellipse design methods are used to design the cross section of double S-bend nozzle. Taking unsteady flow information as the equivalent sound source, the noise signal at the far-field monitoring points were calculated with Ffowcs Williams–Hawkings (FW–H) method, and then, the sound source characteristics of the double S-bend nozzle are analyzed. Findings The results show that the internal flow of the S-bend nozzle with rectangular section is smoothed and the aerodynamic performance is better than super-ellipse section, the shear layer length of rectangular section is longer, the thickness is smaller and the mixing ability is stronger. The sound pressure level of the two S-bend nozzles decreases with the increase of the monitoring angle, and the sound pressure on the horizontal plane is greater than the vertical plane. In the direction of 40°–120°, the jet noise of rectangular nozzle is smaller, and the multiparameter coupled rectangular cross section structure is more applicable. Practical implications It is beneficial to reduce the jet noise of the engine tail nozzle and improve the stealth performance of the aircraft. Originality/value There is very little research on the jet noise characteristics of the double S-bend nozzle. The multiparameter coupling and the super-ellipse method are used to design the nozzle flow section to study the aerodynamic performance and jet noise characteristics of the double S-bend nozzle and to improve the acoustic stealth characteristics of the aircraft.

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A computational study of two-dimensional serpentine nozzle performance with different annular mixer configurations

Cited by 7 publications

References 32 publications

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

A Numerical Investigation of Film Cooling under the Effects of Different Adverse Pressure Gradients

Research on jet noise characteristics of aeroengine double S-bend nozzles with different cross sections

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