Design of Thrust-Optimized Scramjet Nozzle and Its Concise Estimation Method

Chen, Kuangshi; Xu, Jinglei; Qin, Qihao; Xiong, Wentao

doi:10.2514/1.j059846

Cited by 5 publications

(2 citation statements)

References 43 publications

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“…Subsequently, Yu [9] developed a nozzle design method based on the inverse design method, which can constrain the absolute size and position of the inlet and outlet. Chen [10] proposed a design method for the 2D thrust-optimized single expansion ramp nozzle(SERN), which increased the axial thrust by 6.38% and the lift by 180%, further revealing the relationship between aerodynamic performance and geometric design conditions.…”

Section: Introductionmentioning

confidence: 99%

Maximum thrust nozzle based on height constraint

Huang,

Xu,

2023

Preprint

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Hypersonic aircraft focuses more on the integration of aircraft and engine than ordinary aircraft owing to high performance requirements, and the nozzle design is reflected in the required large area ratio of nozzle inlet and outlet and the compactness of the overall size of the aircraft. In this study, the height constraint is directly introduced into the maximum thrust nozzle design method. A new method for designing nozzles under the height constraints that consults the maximum thrust theory is proposed. Initially, the condition that the nozzle reaches the maximum thrust under the height constraint is deduced mathematically. Then, a nozzle design method satisfying the height constraint is computed using the method of characteristics (MOC). Subsequently, the influence of the design parameters on the design method is studied parametrically. Results show that Mach number scale and asymmetrical factors can affect ramp length and flap length of the nozzle, respectively. These factors great influence the axial thrust performance and lift under a specific height constraint. Compared with the traditional truncation design method, the thrust coefficient and lift increased by 11.93% and 138.45% respectively.

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Section: Introductionmentioning

confidence: 99%

Maximum thrust nozzle based on height constraint

Huang,

Xu,

2023

Preprint

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“…Li et al (2008) studied the influence of geometric parameters such as divergence angle, total length, height ratio, fairing length and fairing angle on the performance of the scramjet nozzle. Chen et al (2021) improved the performance of the scramjet nozzle by optimizing the geometric structure parameters. Wen et al (2011) presented the study on the influence of nozzle inlet Mach number on the performance of scramjet nozzle.…”

Section: Introductionmentioning

confidence: 99%

Combined effects of inlet airflow temperature and upper expansion angle on the performance of scramjet nozzle

Sun

Duan

et al. 2022

AEAT

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Purpose The purpose of this paper is to study the combined effects of inlet airflow temperature and the expansion angle of the upper expansion surface (upper expansion angle) on the performance of the scramjet nozzle. Design/methodology/approach The Spalart-Allmaras turbulence two-dimensional model of the nozzle is established for the study. The influence of inlet airflow temperature on the performance of the nozzle is analyzed by detecting the change of the wall pressure of the nozzle. The three angles are chosen for the upper expansion angle (βb) in the model: 8°, 12° and 16°. The temperature of inlet airflow is 600–1,800 K. Findings The study results show that when the βb is 8° and 16°, the wall pressure of the nozzle has a complicated and large fluctuation with the inlet airflow temperature, while the wall pressure has little change as βb is 12°; the thrust coefficient, pitching moment coefficient and lift coefficient of the nozzle fluctuate greatly with the increase of the inlet airflow temperature when βb is 8° and 16°, while the thrust coefficient, pitching moment coefficient and lift coefficient have little fluctuation as βb is 12°. Originality/value The study of the combined effects of the inlet airflow temperature and upper expansion angle on the performance of the scramjet nozzle can provide guidance for the design of scramjet nozzles.

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Three issues on nozzle thrust performance in cold-to-hot correlation considering variable specific heat effect

Chen

Qin

et al. 2022

Physics of Fluids

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A high-temperature effect is crucial in cold-to-hot correlation for thrust nozzles to employ experimental data of cold flow to predict the real flight performance of hot gas. The high-temperature nozzle flow behaves beyond the classical gas dynamics and restricts the feasibility of cold-flow experiments, and it becomes more severe due to the species transformation from cold air to hot gas when safety and cost are considered. For an in-depth awareness, this work refines three fundamental issues regarding the high-temperature variable specific heat effect on nozzle flow characteristics. A comprehensive analysis is performed from theory to applications. First, the flow properties of calorically perfect gas (CPG) and thermally perfect gas (TPG) are distinguished and connected via the basic flow equations. One-dimensional flow theory is extended by the generalized stagnation–static gas functions for TPG. The unanticipated intersections within pressure are discovered, which could produce substantial perplexities in nozzle performance determinations. Second, the pros and cons of two homologous nozzle thrust coefficients are clarified on application objects, definition methods, and solution manners. It is proved that temperature has no influence on thrust coefficients for CPG, while the variable specific heat effect might induce three types of false-positive thrust coefficients, to make flow state unidentified, and further shake the baseline of nozzle performance. Third, for the aggravated variable specific heat effect in cold-to-hot correlation from air to hot gas, two methods are proposed with reliable verifications to solve this issue through introducing a novel concept of relative nozzle operating conditions.

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Design of Thrust-Optimized Scramjet Nozzle and Its Concise Estimation Method

Cited by 5 publications

References 43 publications

Maximum thrust nozzle based on height constraint

Maximum thrust nozzle based on height constraint

Combined effects of inlet airflow temperature and upper expansion angle on the performance of scramjet nozzle

Three issues on nozzle thrust performance in cold-to-hot correlation considering variable specific heat effect

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