Aerospace Science and Technology
Mohammad Hossein Moghimi EsfandAbadi; Adnan Mohammadi; Mohammad Hassan Djavareshkian
Abstract
This research delves into the intricate realm of supersonic inlet design for ramjet engines, honing in on the critical aerodynamic considerations and optimization of performance factors. At Mach 2.5, the study meticulously scrutinizes pivotal design parameters, including the placement and number of inclined ...
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This research delves into the intricate realm of supersonic inlet design for ramjet engines, honing in on the critical aerodynamic considerations and optimization of performance factors. At Mach 2.5, the study meticulously scrutinizes pivotal design parameters, including the placement and number of inclined shocks, cowl-lip positioning, throat area, spike location, and diffuser length. Computational fluid dynamics simulations are harnessed to unravel the intricate flow dynamics and assess the proposed inlet geometry's performance.The findings reveal a nuanced relationship between back pressure and shock wave positioning, where increasing back pressure initiates a shift in the shock wave, impacting the flow state. The paper delineates this transition, emphasizing the pivotal back pressure range of 300,000 to 350,000 pascals, where optimal shock wave alignment corresponds with design parameters, achieving a supercritical state.However, elevating back pressure beyond this range triggers a sub-critical state and mass flow overflow as the shock exits the throat.the study explores various performance metrics, encompassing drag coefficient, distortion coefficient, mass flow ratio and total pressure recovery under varying back pressure conditions. The outcomes underscore the merits of higher back pressures, which mitigate drag coefficient and distortion while amplifying TPR.In the sub-critical state, MFR diminishes due to shock wave displacement beyond the intake opening.This research illuminates the intricate dance of aerodynamics within ramjet engine inlets and underscores the paramount significance of optimizing inlet geometry to unlock heightened performance. It effectively encapsulates the essence of the full article, enticing readers to embark on a deeper exploration of this crucial area of aerospace engineering.
Aerospace Science and Technology
Omid Habibi; Reza Ebrahimi; Hassan Karimi Mazraeh Shahi
Volume 14, Issue 2 , October 2021, , Pages 141-151
Abstract
The nozzle, an end-element of the propulsive process Cycle, represents a critical part of any aerospace vehicle. The task of accelerating and efficiently exhausting combusted and reactive gases according to the delivered thrust represents the main objective of the propulsion system design. Flow separation ...
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The nozzle, an end-element of the propulsive process Cycle, represents a critical part of any aerospace vehicle. The task of accelerating and efficiently exhausting combusted and reactive gases according to the delivered thrust represents the main objective of the propulsion system design. Flow separation in supersonic convergent–divergent nozzles has been the subject of several experimental and numerical studies in the past. Now, with the renewed interest in supersonic flights and space vehicles, the subject has become increasingly important, especially for aerospace applications (rockets, missiles, supersonic aircrafts, etc). Flow separation in supersonic nozzles is a basic fluid dynamics phenomenon that occurs at a certain pressure ratio of chamber to ambient pressure, resulting in shock formation and shock/turbulent-boundary layer interaction inside the nozzle. From purely gas-dynamics point of view, this problem involves basic structure of shock interactions with separation shock, which consists of incident shock, Mach reflections, reflected shock, triple point and slip lines. In this article A Review on Flow Separation Phenomenon for Supersonic Convergent–Divergent Nozzles has been investigated.
