Aerospace Knowledge and Technology Journal

Aerospace Knowledge and Technology Journal

Improving the performance of a specific ultrasonic inlet opening, using a micro-ramp and chamfering between the two parts of the spike divergence

Document Type : Research Paper

Authors
Mahmoud Adami 1
Hamid Salar Vand 2
Ali-reza Mohammadi Kamal Abadi 3
1 Associate Professor, Faculty of Mechanical Engineering, Malek-ashtar University of Technology, Iran.
2 Ph.D. Researcher, Faculty of Mechanical Engineering, Malek-ashtar University of Technology
3 M.Sc Student, Faculty of Mechanical Engineering, Malek-ashtar University of Technology
Abstract
The present study was designed based on a ram-jet ultrasonic inlet, under conditions of 261 K, 32 kPa and Mach 2. The initially optimized inlet opening was improved using two innovative methods. Two auxiliary methods are a) curving between two parts of spike divergence b) using microramp on the first stage of spike divergence. The initial optimized geometry formed the final geometry by bending between the two divergence parts of the first spike stage and the second spike stage, that is, bending between two angles of 2.3° and 8° with a curvature radius of 10 cm. Now, the geometry with the radius of curvature of 10 cm was selected as the final geometry, and the inlet opening was simulated using a microramp with a length of 2 mm and a height of 0.08 mm on the spike. In this case, the efficiency of the inlet opening is 0.26% compared to the inlet opening with a curvature radius of 10 cm, and compared to the inlet opening with a curvature radius of 5 cm, it is 0.814%, and compared to the optimized inlet opening. It increased by 1.37 percent and 3.6 percent compared to the reference inlet opening. Also, the fluctuations of Mach number and static pressure (flow distortion) compared to the inlet opening with a radius of curvature between the two parts of the spike divergence of 10 cm by 2.15%, and compared to the inlet opening with a radius of curvature between the two parts of the spike divergence of 5 cm m by 6.65%, compared to the initial optimized inlet opening by 10.7%, and compared to the reference inlet opening by 23.55%.
Keywords
Input span
improved input span
initial optimized input span
final optimized input span.
Subjects
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Aerospace Knowledge and Technology Journal
Volume 15, Issue 1
September 2026
Pages 7-21