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Abstract
This paper aims at developing a performance analysis tool to evaluate the performance and design constraints of a turbine based combined cycle engine concept with the tandem layout for a hypersonic cruise vehicle. To meet the conflict requirements in the long range from take-off to Mach 5, the combine cycle engine applies a variable cycle engine concept via the modulation of five variable geometries and fuel flow. This tool uses one-dimensional aerodynamic thermodynamic analysis techniques, considering the test proved components characteristics and the property of calorically perfect gas etc. The objects oriented software design method is adopted in the tool which can afford a platform suitable for parametric cycle analysis, performance cycle analysis and control law study of the turbofan mode, the ramjet mode and turbo/ram mode transition. Assisted by this tool, parametric cycle analysis of the turbofan mode and the ramjet mode was investigated. It shows recirculation margin is a key factor to be considered in the cycle parameters selection of the turbofan mode; high ramjet afterburner discharge temperature is favorable to the ramjet cycle performance.
... The algorithms used in this method have been demonstrated to have good convergence [12,26,38,39]. Without a specific prototype, this method can still calculate and analyze the steady-state performance by using the general characteristics of the components [12][13][14][15][39][40][41][42][43]. Therefore, the zero-dimensional model numeric simulation method is considered to have strong practicability and flexibility in the preliminary R&D stage of gas turbine engine [23,26,27,[39][40][41][42][43]. ...
... Without a specific prototype, this method can still calculate and analyze the steady-state performance by using the general characteristics of the components [12][13][14][15][39][40][41][42][43]. Therefore, the zero-dimensional model numeric simulation method is considered to have strong practicability and flexibility in the preliminary R&D stage of gas turbine engine [23,26,27,[39][40][41][42][43]. ...
In the process of studying the steady-state performance and component matching of adaptive cycle engines with convertible fan system, it was found that the front fan and aft fan stage have a unique matching problem when the mode select valve is closed and engine is operating at higher Mach number conditions. The cause of this matching problem was studied with numeric simulation in this paper. Based on the features of adaptive cycle engines with convertible fan system, the possible methods and their feasibilities of solving this matching problem were also discussed. According to the results, the flow rate adjustment capacity of the aft fan stage directly determines the occurrence and severity of this matching problem. The matching problem can be ameliorated in some extent by either reducing the design second bypass ratio or adjusting the variable geometry mechanisms, but it cannot be completely solved at the aspect of component matching mechanism.
... Then, the components' operating points are determined by the matching guesses and ACE's overall performance can be calculated easily. More details about the 0D engine performance model can be obtained in the literature [2,28,29]. The arithmetic of this performance model has been tested and verified accurately in many projects [30,31]. ...
... On the other hand, the decrease in A 8 When the ACE operates at the subsonic cruise or supersonic cruise condition, turning down A 28 increases the thrust and decreases the airflow. Directly, turning down A 28 increases the back pressure of FFAN, resulting in the decrease in airflow and FFAN's surge margin. On the other hand, turning down A 28 causes more air flow through RFAN, leading to the increase in LPR's compression work. ...
One advantage of the adaptive cycle engine (ACE) is its ability of throttling with constant airflow by the combined control of variable geometries, resulting in an improvement of spillage drag. However, the improvement is achieved at risk of a complex technical solution and control. This article investigates the selection scheme of variable geometries and engine configuration. It focuses on the performance of a three-stream ACE during throttling, whose configuration and control schedule are simpler than other types of ACEs. Five variable geometries are selected from seven available options through comparison analysis. The uninstalled thrust decreases from 100% to 60.36% during the subsonic throttling and to 59.81% during the supersonic throttling. Benefitting from the decreased spillage drag, the installed performance of the three-stream ACE is improved to some degree during throttling. This improvement is less than the result of a three-bypass ACE, whose configuration and control schedule are more complex. Thus, the three-stream ACE is a compromise design considering the technical risk and variable cycle characteristic, which is a better platform to verify the component technology and control schedule for the further research on a more complex type of ACE.
... These mentioned parameters can be solved numerically by thermodynamic calculation via related formulas. More details of general zero-dimensional aero-engine performance modeling can be found in these references [16][17][18][19][20]. ...
... According to the compression work equation, the unit power of the CDFS, the HPC and the HPT can be described as Eqs. (14)- (16). ...
As an evolutional concept of variable cycle engine, the adaptive cycle engine draws widely attention with high expectations. It combines a variable geometry schedule and component matching principles to demonstrate its advantages such as avoiding severe inlet spillage drag and the wide variable cycle characteristics. Thus, this paper aims at equilibrium running principle analysis on an adaptive cycle engine at variable operating modes, deriving the equilibrium running equations of an adaptive cycle engine for the first time, and exploring the physical essence of components matching principle on the basis of a newly developed nonlinear component-based adaptive cycle engine performance model. It uncovers the physical essence of components matching relationships and provides mathematical derivation of equilibrium running principles which lay theoretical foundation of the variable geometries modulation schedule and overall performance optimization on an adaptive cycle engine.
... More details about general engine performance simulation can be found in the literature. [12,13] The modeling theory and method have been tested and verified accurately. [14,15] No.2 ...
... It is noteworthy that the matching guess vector varies with different control schedules. In order to work out the engine off-design point performance at different working modes, a multi-dimensional Newton-Raphson iteration technique [12,13,16] is used to deal with Eq. (15) which tries to let the residual value vector Z 0 . The algorithm of solving engine nonlinear equations is listed as below. ...
As a novel aero-engine concept, adaptive cycle aero-engines (ACEs) are attracting wide attention in the international aviation industry due to their potential superior task adaptability along a wide flight regime. However, this superior task adaptability can only be demonstrated through proper combined engine control schedule design. It has resulted in an urgent need to investigate the effect of each variable geometry modulation on engine performance and stability. Thus, the aim of this paper is to predict and discuss the effect of each variable geometry modulation on the matching relationship between engine components as well as the overall engine performance at different operating modes, on the basis of a newly developed nonlinear component-based ACE performance model. Results show that at all four working modes, turning down the high pressure compressor variable stator vane, the low pressure turbine variable nozzle, the nozzle throat area, and turning up the core-driven fan stage variable stator vane, the high pressure turbine variable nozzle can increase the thrust at the expense of a higher high pressure turbine inlet total temperature. However, the influences of these adjustments on the trends of various engine components’ working points and working lines as well as the ratio of the rotation speed difference are different from each other. The above results provide valuable guidance and advice for engine combined control schedule design.
... A significant body of investigations has been conducted experimentally recently, such as the TBCC inlet mode transition experiment at NASA Glenn Research Center [8][9][10] and the HYPR90-C demonstrator tests [11,12]. Meanwhile, theoretical studies are also proceeding [13][14][15][16]. Great efforts have been made to maintain high performance and operability of the TBCC engine. ...
For a better understanding of the flow instability in TBCC inlet, the unstart/restart characteristics have been investigated. Firstly, the flow field of TBCC inlet at different transition stages are analyzed. As the splitter rotates from upside to downside (transition from low-speed inlet to high-speed inlet) with a fixed backpressure, the shock train moves downstream. The maximum backpressure that the inlet can tolerate also rises. Secondly, according to the unstart boundary (namely maximum backpressure) and restart boundary, it can be found that if the inlet is propelled to transit from started state to unstarted state, inlet restart cannot be achieved along the same control route. Unstart/restart hysteresis loops in each transition phase are discussed according to the simulation results. Besides the hysteresis behavior under backpressure, the same phenomenon is also observed during the inlet transition process. Finally, the distinctiveness of the hysteresis caused by inlet mode transition is also discussed.
... A Turbine Based Combined Cycle (TBCC) engine is a reusable, low-cost, and high-durability propulsion system. [1][2][3] It is one of the most promising propulsion systems for nextgeneration vehicles. This combined cycle engine can operate well in low and high Mach numbers through a turbine engine and a dual-mode scramjet engine, respectively. ...
The characteristics of unsteady flow in a dual-flowpath inlet, which was designed for a Turbine Based Combined Cycle (TBCC) propulsion system, and the control methods of unsteady flow were investigated experimentally and numerically. It was characterized by large-amplitude pressure oscillations and traveling shock waves. As the inlet operated in supercritical condition, namely the terminal shock located in the throat, the shock oscillated, and the period of oscillation was about 50 ms, while the amplitude was 6 mm. The shock oscillation was caused by separation in the diffuser. This shock oscillation can be controlled by extending the length of diffuser which reduces pressure gradient along the flowpath. As the inlet operated in critical condition, namely the terminal shock located at the shoulder of the third compression ramp, the shock oscillated, and the period of oscillation was about 7.5 ms, while the amplitude was 12 mm. At this condition, the shock oscillation was caused by an incompatible backpressure in the bleed region. It can be controlled by increasing the backpressure of the bleed region.
... More details about general 0D engine performance simulation can be found in the literature. 21,22 Other important features of the engine module are shown below. ...
One of the most critical challenges for turbine-based combined cycle propulsion systems utilized in hypersonic civil aircrafts (Mach 0 to Mach 5) lies in guaranteeing the propulsion system to operate efficiently and stably along a very wide operating range. This has resulted in a need to investigate the matching restraints between the inlet and turbine-based combined cycle engine and nozzle from the integration point of view at the early stage of design. To get a good understanding of this integration concept design process, in this article, several basic design principles were first put forward. Next, a fast, versatile and trusted modular analysis tool for this concept design was developed and implemented. Third, several issues on this concept were analyzed including the design issues, the mechanisms of the variable geometries as well as the control schedules. Finally, a solution for the turbine-based combined cycle propulsion system was carried out and discussed. The results show that at least 11 total variables were required to be adopted in the variable cycle propulsion system to meet the basic mission requirements for Mach 5 civil airplane. How to guarantee these variable geometries function efficiently and reliably along the wide flight regime is one of the most critical technology challenges to make this concept feasible. The uniqueness of the developed analysis tool lies in that it affords a platform capable of investigating the design constraints and the matching relationships between the various propulsion components along a wide operating range, which is beneficial to predict the potential critical technological barriers at the early design stage.
Two sets of propulsion concept were analyzed based the existent low bypass ratio augmented turbofan engine with mixed exhaust nozzle, in order to meet the mission requirements on the low Mach propulsion system (Ma ≤ 3.5) in the hypersonic transportation. The result shows: as for the turbofan (TF) concept, by means of optimizing the control law of the base turbofan engine, total pressure difference between the two streams at the mixed zone was effectively reduced, contributing to flow organization at the afterburner inlet and flame stability. Also, the optimized control law contributes to lower specific fuel consumption. As for the turbofan/ramjet combined cycle engine concept with over-under configuration compared with the TF concept, independent inlet and nozzle were both required for the two engine models due to the aerodynamic mismatch during mode transition, which would increase the structure complexity, weight and technology risk.
Engi neering Research for Super Hyper-Sonic Transport Propulsion System( HYPR)
- Makoto Okazaki
- Kazuo Miyazawa
- Kazuhiko Ishizawa
Makoto Okazaki, Kazuo Miyazawa, Kazuhiko Ishizawa.Engi neering
Research for Super Hyper-Sonic Transport Propulsion System( HYPR)
Combine Cycle Engine Research on Japanese HYPR Program
- H Miyagi
- H Kimura
- Ki Shi
Miyagi H, Kimura H, Ki shi K, et al. Combine Cycle Engine Research
on Japanese HYPR Program[ A].