The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Akiko Matsuo - One of the best experts on this subject based on the ideXlab platform.
-
critical condition of inner cylinder radius for sustaining rotating Detonation Waves in rotating Detonation engine thruster
Proceedings of the Combustion Institute, 2019Co-Authors: Akira Kawasaki, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Keisuke Goto, Tomoya Inakawa, Ikkoh FunakiAbstract:Abstract We describe the critical condition necessary for the inner cylinder radius of a rotating Detonation engine (RDE) used for in-space rocket propulsion to sustain adequate thruster performance. Using gaseous C2H4 and O2 as the propellant, we measured thrust and impulse of the RDE experimentally, varying in the inner cylinder radius ri from 31 mm (typical annular configuration) to 0 (no-inner-cylinder configuration), while keeping the outer cylinder radius (ro = 39 mm) and propellant injector position (rinj = 35 mm) constant. In the experiments, we also performed high-speed imaging of self-luminescence in the combustion chamber and engine plume. In the case of relatively large inner cylinder radii (ri = 23 and 31 mm), rotating Detonation Waves in the combustion chamber attached to the inner cylinder surface, whereas for relatively small inner cylinder radii (ri = 0, 9, and 15 mm), rotating Detonation Waves were observed to detach from the inner cylinder surface. In these small inner radii cases, strong chemical luminescence was observed in the plume, probably due to the existence of soot. On the other hand, for cases where ri = 15, 23, and 31 mm, the specific impulses were greater than 80% of the ideal value at correct expansion. Meanwhile, for cases ri = 0 and 9 mm, the specific impulses were below 80% of the ideal expansion value. This was considered to be due to the imperfect Detonation combustion (deflagration combustion) observed in small inner cylinder radius cases. Our results suggest that in our experimental conditions, ri = 15 mm was close to the critical condition for sustaining rotating Detonation in a suitable state for efficient thrust generation. This condition in the inner cylinder radius corresponds to a condition in the reduced unburned layer height of 4.5–6.5.
-
application of Detonation Waves to rocket engine chamber
2018Co-Authors: Jiro Kasahara, Ken Matsuoka, Akiko Matsuo, Ikkoh Funaki, Yuichi Kato, Kazuaki Ishihara, Keisuke Goto, Hideki Moriai, Daisuke Nakata, Kazuyuki HigashinoAbstract:We present the results of experiments performed with a rotating Detonation engine using continuous Detonation in an annular combustor to create thrust. Detonation Waves propagate in a supersonic and very small region, allowing shortening of the combustor. The combustor of RDE causes high-pressure loss when the propellant is injected, and cooling is necessary due to high heat flux. However, the combustion efficiency of Detonation combustion in an annular combustor is the most important, but have not been fully elucidated. In addition, the influence of the injector shape and direct cooling of a rotating Detonation combustor require clarification. This paper reports the measurement results of combustor stagnation pressure and thrust, the influence of injector shape on c* efficiency, and the estimate of heat flux. The c* efficiency was 88–100% when we used the convergent or convergent-divergent nozzle and the equivalence ratio was less than 1.0. The shape of the injector influenced wave propagation mode, but the mode did not change the c* efficiency. We estimated time-spatial average heat flux from the terminal temperature, and the heat flux was 8.1 ± 1.8 MW/m2 in no water injection condition. The rocket RDE sled test was successfully performed. The total mass of the rocket RDE system was 58.3 kg, total time averaged thrust was 201 N, the time averaged mass flow rate was 143 g/s, and the specific impulse was 144 s.
-
experimental study of the structure of forward tilting rotating Detonation Waves and highly maintained combustion chamber pressure in a disk shaped combustor
Proceedings of the Combustion Institute, 2017Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Ikkoh FunakiAbstract:Abstract The structure of Detonation Waves in rotating Detonation combustors (RDCs) and their combustion chamber pressure characteristics have not yet been fully clarified due to the complexity and shape of the RDC combustion chamber. Therefore, a disk-shaped RDC was used in this study to visualize the inside of the combustion chamber while simultaneously measuring its pressure. Forward-tilting rotating Detonation Waves were observed, and a schematic was proposed for them. The initial velocity of the forward-tilting rotating Detonation wave was 1200 ± 160 m/s, and it subsequently increased to 1600 ± 160 m/s; meanwhile, the Chapman–Jouguet (CJ) velocity was 2376 m/s. There are several reasons why the velocity may have differed so widely from the CJ value, including the presence of burned gas in front of the Detonation wave, the complicated wave structure due to non-uniformity of the mixture in the RDC, insufficient propellant mixing, and the difference between the true and actual wave propagation direction. The velocity and amplitude of the combustion chamber static pressure appeared to be correlated. Averaged combustion chamber static pressure reached 0.432 MPa, which was 89.0% and 92.8% of the fuel and oxidizer plenum pressure, respectively. Dynamic pressure was also estimated using an equilibrium calculation. The resulting dynamic pressure was 0.008 MPa, and estimated total pressure was 0.440 MPa; these values were 90.1% and 94.6% of the fuel and oxidizer plenum total pressure, respectively, even though pressure was lost through the small diameter injector holes.
-
experimental visualization of the structure of rotating Detonation Waves in a disk shaped combustor
Journal of Propulsion and Power, 2017Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Yoshiki Kumazawa, Jumpei Fujii, Ikkoh FunakiAbstract:The rotating Detonation engine is a propulsion system that obtains thrust using continuously existing Detonation Waves. A rotating Detonation combustor usually has an annular shape that allows Detonation Waves to propagate in the circumferential direction. In this study, we used a disk-shaped rotating Detonation combustor with a combustion chamber with flat-plane glass walls to observe the structure of the phenomena. Self-luminescence, shadowgraphs, and schlieren visualization experiments were performed and compared. Results revealed that Detonation Waves were propagating in a mixture layer of three gases, fuel, oxidizer, and burned gas at 1600 to 900 m/s; Chapman-Jouguet velocity was 2376 m/s. Waves maintained a three-dimensional complicated wave shape in the disk-shaped combustion chamber with parallel-jet injectors.
-
visualization of rotating Detonation Waves in a plane combustor with a cylindrical wall injector
53rd AIAA Aerospace Sciences Meeting 2015, 2015Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Ikkoh FunakiAbstract:A Rotating Detonation Engine (RDE) has higher thermal efficiency and simpler structure than a conventional gas turbine engine. Therefore, many research institutions has been investigating RDEs. Property of propagation of Detonation Waves in a RDE, however, has not been fully elucidated yet. Toward the practical use of RDEs, clarifying the propagation characteristics of Detonation Waves in RDEs is important. In the present study,we fabricated a plane RDE combustor with a cylindrical wall injector and performed visualization experiment. Propagation speed of the combustion Waves that was observed in this experiment had reached to about 1300 – 1100 m/s, that is about 55 – 45 % of Chapman Jouguet Detonation velocity.
Zonglin Jiang - One of the best experts on this subject based on the ideXlab platform.
-
formation of stabilized oblique Detonation Waves in a combustor
Combustion and Flame, 2021Co-Authors: Zijian Zhang, Chihyung Wen, Wenshuo Zhang, Yunfeng Liu, Zonglin JiangAbstract:Abstract Initiation and stabilization of oblique Detonation Waves (ODWs) are important to the successful application of oblique Detonation engines (ODEs), which, however, have been rarely studied under realistic combustor conditions. In this study, the flow structures, stabilization characteristics and potential thrust performance (under different combustor's geometries with different ODW reflection locations) in a typical hydrogen-fueled ODE combustor are numerically studied by solving the two-dimensional multi-species Reynolds-averaged conservation equations with a detailed hydrogen combustion mechanism. Results suggest that all the Detonation Waves/shock Waves can be stabilized in the space-confined combustor, and the boundary layer separation induced by the ODW-boundary layer interaction is found crucial to determining the types of combustion mode in the combustor. Except for the expected ODW-induced combustion, fast combustion induced by a stabilized overdriven normal Detonation wave (NDW) may exist in the combustor simultaneously (even up to a large extent, >73.7%). It is demonstrated that the stabilization of the overdriven NDW in the combustor can be attributed to the formation of an effective aerodynamic convergent-divergent nozzle that quickly accelerates the subsonic flow behind the NDW to supersonic, preventing downstream disturbances from propagating upstream. Benefiting from the chemical equilibrium shift caused by the expansion effect of the flow, more heat is released to compensate for the compression loss and the simulated thrust performance is shown not deteriorate significantly even with a large percentage of NDW-induced combustion existing in the ODE combustor. This work would be beneficial to the future developments of the ODEs.
-
Numerical investigation of wavelet features in rotating Detonations with a two-step induction-reaction model
International Journal of Hydrogen Energy, 2020Co-Authors: Honghui Teng, Lin Zhou, Pengfei Yang, Zonglin JiangAbstract:Abstract The wavelet features of rotating Detonation Waves (RDWs) are numerically investigated using Euler equations and a two-step induction-reaction model. The effects of the inflow stagnation temperature Tst and the heat release rate kR on the number, height and intensity of the RDWs are discussed in this study. An increase in the stagnation temperature results in more Detonation Waves in a combustion chamber, which indicates the number of RDWs is sensitivity to the thermodynamic state of the reactants. As the heat release rate decreases, the number of Detonation wave decreases and an unstable wavelet pattern is observed. This is represented as the oscillation in height and intensity of the Detonation. In addition, some numerical cases are performed to determine the effects of ignition patterns on the number of RDWs. The features of the flow fields are analyzed using varied inflow stagnation temperature and initiation patterns, identifying the co-existence of different wavelet configurations.
-
a numerical study on the instability of oblique Detonation Waves with a two step induction reaction kinetic model
Proceedings of the Combustion Institute, 2019Co-Authors: Honghui Teng, Pengfei Yang, Zonglin JiangAbstract:Abstract In this study, the surface instability of oblique Detonation Waves (ODW) formed by two-dimensional, semi-infinite wedges is investigated numerically by solving the unsteady Euler equations with a two-step induction–reaction kinetic model. The chemical kinetic model introduces two length scales, namely, induction and reaction lengths, which can be varied independently to change the sensitivity of the chemical reaction and also the shape of the reaction zone structure. The present numerical results elucidate that both smooth and cellular ODW surfaces may appear after the initiation, and the surface becomes unstable when the reaction zone length decreases while keeping the induction zone the same as observed in normal Detonation wave propagation. To investigate the degree of instability quantitatively, the oscillations of post-shock pressure inside the reaction zone are examined, and analyzed using Fast Fourier Transformation (FFT) to get the power spectral density (PSD). Results suggest that there are two types of unstable surfaces, one is dominated by random disturbances, without distinct large amplitude unstable modes, on the ODW surface due to the upstream perturbations interacting with the incoming flow and continuous generation within the structure, while the other formed from the inherent disturbances convected from upstream in the initiation region and later developed into dominant unstable modes via an apparent bifurcation pattern. Equivalent to normal Detonations, the stability parameter χ as defined by the ratio of induction length over the reaction length multiplied by the global reduced activation energy can also be used to describe qualitatively the trends of the ODW surface instability observed in this study.
-
numerical investigation on the induction zone structure of the oblique Detonation Waves
Computers & Fluids, 2014Co-Authors: Honghui Teng, Yining Zhang, Zonglin JiangAbstract:Oblique Detonation Waves are simulated to study the induction zone structures with different incident Ma numbers. Three kinds of shock configurations are observed at the end of the induction zone, which are the lambda-shaped shock, the X-shaped shock and the Y-shaped shock. The X-shaped and Y-shaped shocks appear when the incident Ma is low, and the Y-shaped shock associated with the complicated unstationary process. The induction zone length reaches the maximum value when the X-shaped shock changes into the Y-shaped shock, which indicates different mechanisms deciding the induction zone. The oblique shock wave dominates the induction zone when the incident Ma is high, while the oblique Detonation wave dominates the induction zone when the incident Ma is low. (c) 2014 Elsevier Ltd. All rights reserved.
Jianping Wang - One of the best experts on this subject based on the ideXlab platform.
-
numerical investigation of two wave collision and wave structure evolution of rotating Detonation engine with hollow combustor
International Journal of Hydrogen Energy, 2018Co-Authors: Xinmeng Tang, Mingyi Luan, Shujie Zhang, Jianping WangAbstract:Abstract A three-dimensional numerical simulation of rotating Detonation engine (RDE) with hollow combustor is performed to analyze wave structure evolution systematically. Wave structure evolution is classified into four categories, namely two-wave collision (counter-rotating Waves), abscission of Detonation tail, and shock wave to Detonation transition. Two-wave collision consists of symmetric Detonation collision, asymmetric Detonation collision, and Detonation/shock collision. Two symmetric Detonation Waves turn into shock Waves after collision. Collision of asymmetric Detonation Waves creates single Detonation wave. The Detonation/shock collision decreases the Detonation wave intensity. Abscission of Detonation tail and shock to Detonation transition can both create single Detonation wave or two opposite-direction Detonation Waves, depending on the wave hitting angle and the amount of fresh gas. All phenomena mentioned above affect the number of Detonation Waves in the combustion chamber.
-
Multiple ignitions and the stability of rotating Detonation Waves
Applied Thermal Engineering, 2016Co-Authors: Jianping WangAbstract:Abstract We perform a numerical study on rotating Detonation engines (RDE). The simulations demonstrate the feasibility of creating multiple Detonation Waves and examine their stabilization process. The computations are based on the three-dimensional Euler equations with reactive sources. The Arrhenius chemistry model is used to calculate the reaction rate of the pre-mixed stoichiometric hydrogen-air mixture. The simulations show the oscillation phenomenon characterized by the pressure-time traces and the stabilization process. Also, the results indicate the existence of one-, two-, and eight-wave propagation modes in the fully-developed Detonation flow. The initial Detonation Waves dominate the flow throughout the stabilization process in the one- and two-wave modes. On the other hand, the eight-wave mode is the result of the generation of new Detonation Waves during the intermediate stage. The simulations are compared with the experimental studies to confirm the existence of the multi-wave modes discussed herein. In addition, it is found that the velocity of Detonation Waves decreases with the increase of the number of Detonation Waves, which is also reported in some experiments.
-
induction for multiple rotating Detonation Waves in the hydrogen oxygen mixture with tangential flow
International Journal of Hydrogen Energy, 2014Co-Authors: Yuhui Wang, Jianping WangAbstract:Abstract Rotating Detonation engines are studied more and more widely because of high thermodynamic efficiency and high specific impulse. Generally one Detonation wave exists in the engines but sometimes multiple Detonation Waves appear, as is complicated and difficult to explain. Increasing the number of rotating Detonation Waves uniforms the flow field and weakens the combustion instabilities. A controllable way to induce multiple Detonation Waves is introduced here. Rotating Detonation engine runs with a single Detonation wave or multiple Detonation Waves were both conducted. Pressure sensors were used to record the pressure traces of rotating Detonation Waves and gas flow controllers controlled the flow rates of reactants. Tangential flow of reactants from the predetonator produces shock Waves moving upstream, inducing multiple rotating Detonation Waves when there is axial flow of reactants from the head of the combustor. The maximum number of Detonation Waves is subject to the flow rates.
Honghui Teng - One of the best experts on this subject based on the ideXlab platform.
-
Numerical investigation of wavelet features in rotating Detonations with a two-step induction-reaction model
International Journal of Hydrogen Energy, 2020Co-Authors: Honghui Teng, Lin Zhou, Pengfei Yang, Zonglin JiangAbstract:Abstract The wavelet features of rotating Detonation Waves (RDWs) are numerically investigated using Euler equations and a two-step induction-reaction model. The effects of the inflow stagnation temperature Tst and the heat release rate kR on the number, height and intensity of the RDWs are discussed in this study. An increase in the stagnation temperature results in more Detonation Waves in a combustion chamber, which indicates the number of RDWs is sensitivity to the thermodynamic state of the reactants. As the heat release rate decreases, the number of Detonation wave decreases and an unstable wavelet pattern is observed. This is represented as the oscillation in height and intensity of the Detonation. In addition, some numerical cases are performed to determine the effects of ignition patterns on the number of RDWs. The features of the flow fields are analyzed using varied inflow stagnation temperature and initiation patterns, identifying the co-existence of different wavelet configurations.
-
numerical investigation on the initiation of oblique Detonation Waves in stoichiometric acetylene oxygen mixtures with high argon dilution
Combustion and Flame, 2019Co-Authors: Yuhang Zhang, Yishen Fang, Honghui TengAbstract:Abstract Oblique Detonation Waves (ODWs) in stoichiometric acetylene-oxygen mixtures, highly diluted by 81–90% argon, are studied using the reactive Euler equations with a detailed chemistry model. Numerical results show that the incident Mach number M0 changes the ODW initiation structure, giving both the smooth transition in the case of M0 = 10 and the abrupt transition in the case of M0 = 7. By comparing results of numerical simulation and theoretical analysis, the initiation processes are found to be chemical kinetics-controlled regardless of M0, different from those in hydrogen-air mixtures which are wave-controlled in the low M0 regime. The argon dilution effect on the initiation morphology is investigated, showing that the structures are determined by the dilution ratio and M0 collectively. However, the initiation length is found to be independent of the dilution ratio and only determined by M0, which is attributed to the competing effect of the high density and high temperature.
-
a numerical study on the instability of oblique Detonation Waves with a two step induction reaction kinetic model
Proceedings of the Combustion Institute, 2019Co-Authors: Honghui Teng, Pengfei Yang, Zonglin JiangAbstract:Abstract In this study, the surface instability of oblique Detonation Waves (ODW) formed by two-dimensional, semi-infinite wedges is investigated numerically by solving the unsteady Euler equations with a two-step induction–reaction kinetic model. The chemical kinetic model introduces two length scales, namely, induction and reaction lengths, which can be varied independently to change the sensitivity of the chemical reaction and also the shape of the reaction zone structure. The present numerical results elucidate that both smooth and cellular ODW surfaces may appear after the initiation, and the surface becomes unstable when the reaction zone length decreases while keeping the induction zone the same as observed in normal Detonation wave propagation. To investigate the degree of instability quantitatively, the oscillations of post-shock pressure inside the reaction zone are examined, and analyzed using Fast Fourier Transformation (FFT) to get the power spectral density (PSD). Results suggest that there are two types of unstable surfaces, one is dominated by random disturbances, without distinct large amplitude unstable modes, on the ODW surface due to the upstream perturbations interacting with the incoming flow and continuous generation within the structure, while the other formed from the inherent disturbances convected from upstream in the initiation region and later developed into dominant unstable modes via an apparent bifurcation pattern. Equivalent to normal Detonations, the stability parameter χ as defined by the ratio of induction length over the reaction length multiplied by the global reduced activation energy can also be used to describe qualitatively the trends of the ODW surface instability observed in this study.
-
numerical investigation on the induction zone structure of the oblique Detonation Waves
Computers & Fluids, 2014Co-Authors: Honghui Teng, Yining Zhang, Zonglin JiangAbstract:Oblique Detonation Waves are simulated to study the induction zone structures with different incident Ma numbers. Three kinds of shock configurations are observed at the end of the induction zone, which are the lambda-shaped shock, the X-shaped shock and the Y-shaped shock. The X-shaped and Y-shaped shocks appear when the incident Ma is low, and the Y-shaped shock associated with the complicated unstationary process. The induction zone length reaches the maximum value when the X-shaped shock changes into the Y-shaped shock, which indicates different mechanisms deciding the induction zone. The oblique shock wave dominates the induction zone when the incident Ma is high, while the oblique Detonation wave dominates the induction zone when the incident Ma is low. (c) 2014 Elsevier Ltd. All rights reserved.
Jiro Kasahara - One of the best experts on this subject based on the ideXlab platform.
-
critical condition of inner cylinder radius for sustaining rotating Detonation Waves in rotating Detonation engine thruster
Proceedings of the Combustion Institute, 2019Co-Authors: Akira Kawasaki, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Keisuke Goto, Tomoya Inakawa, Ikkoh FunakiAbstract:Abstract We describe the critical condition necessary for the inner cylinder radius of a rotating Detonation engine (RDE) used for in-space rocket propulsion to sustain adequate thruster performance. Using gaseous C2H4 and O2 as the propellant, we measured thrust and impulse of the RDE experimentally, varying in the inner cylinder radius ri from 31 mm (typical annular configuration) to 0 (no-inner-cylinder configuration), while keeping the outer cylinder radius (ro = 39 mm) and propellant injector position (rinj = 35 mm) constant. In the experiments, we also performed high-speed imaging of self-luminescence in the combustion chamber and engine plume. In the case of relatively large inner cylinder radii (ri = 23 and 31 mm), rotating Detonation Waves in the combustion chamber attached to the inner cylinder surface, whereas for relatively small inner cylinder radii (ri = 0, 9, and 15 mm), rotating Detonation Waves were observed to detach from the inner cylinder surface. In these small inner radii cases, strong chemical luminescence was observed in the plume, probably due to the existence of soot. On the other hand, for cases where ri = 15, 23, and 31 mm, the specific impulses were greater than 80% of the ideal value at correct expansion. Meanwhile, for cases ri = 0 and 9 mm, the specific impulses were below 80% of the ideal expansion value. This was considered to be due to the imperfect Detonation combustion (deflagration combustion) observed in small inner cylinder radius cases. Our results suggest that in our experimental conditions, ri = 15 mm was close to the critical condition for sustaining rotating Detonation in a suitable state for efficient thrust generation. This condition in the inner cylinder radius corresponds to a condition in the reduced unburned layer height of 4.5–6.5.
-
application of Detonation Waves to rocket engine chamber
2018Co-Authors: Jiro Kasahara, Ken Matsuoka, Akiko Matsuo, Ikkoh Funaki, Yuichi Kato, Kazuaki Ishihara, Keisuke Goto, Hideki Moriai, Daisuke Nakata, Kazuyuki HigashinoAbstract:We present the results of experiments performed with a rotating Detonation engine using continuous Detonation in an annular combustor to create thrust. Detonation Waves propagate in a supersonic and very small region, allowing shortening of the combustor. The combustor of RDE causes high-pressure loss when the propellant is injected, and cooling is necessary due to high heat flux. However, the combustion efficiency of Detonation combustion in an annular combustor is the most important, but have not been fully elucidated. In addition, the influence of the injector shape and direct cooling of a rotating Detonation combustor require clarification. This paper reports the measurement results of combustor stagnation pressure and thrust, the influence of injector shape on c* efficiency, and the estimate of heat flux. The c* efficiency was 88–100% when we used the convergent or convergent-divergent nozzle and the equivalence ratio was less than 1.0. The shape of the injector influenced wave propagation mode, but the mode did not change the c* efficiency. We estimated time-spatial average heat flux from the terminal temperature, and the heat flux was 8.1 ± 1.8 MW/m2 in no water injection condition. The rocket RDE sled test was successfully performed. The total mass of the rocket RDE system was 58.3 kg, total time averaged thrust was 201 N, the time averaged mass flow rate was 143 g/s, and the specific impulse was 144 s.
-
experimental study of the structure of forward tilting rotating Detonation Waves and highly maintained combustion chamber pressure in a disk shaped combustor
Proceedings of the Combustion Institute, 2017Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Ikkoh FunakiAbstract:Abstract The structure of Detonation Waves in rotating Detonation combustors (RDCs) and their combustion chamber pressure characteristics have not yet been fully clarified due to the complexity and shape of the RDC combustion chamber. Therefore, a disk-shaped RDC was used in this study to visualize the inside of the combustion chamber while simultaneously measuring its pressure. Forward-tilting rotating Detonation Waves were observed, and a schematic was proposed for them. The initial velocity of the forward-tilting rotating Detonation wave was 1200 ± 160 m/s, and it subsequently increased to 1600 ± 160 m/s; meanwhile, the Chapman–Jouguet (CJ) velocity was 2376 m/s. There are several reasons why the velocity may have differed so widely from the CJ value, including the presence of burned gas in front of the Detonation wave, the complicated wave structure due to non-uniformity of the mixture in the RDC, insufficient propellant mixing, and the difference between the true and actual wave propagation direction. The velocity and amplitude of the combustion chamber static pressure appeared to be correlated. Averaged combustion chamber static pressure reached 0.432 MPa, which was 89.0% and 92.8% of the fuel and oxidizer plenum pressure, respectively. Dynamic pressure was also estimated using an equilibrium calculation. The resulting dynamic pressure was 0.008 MPa, and estimated total pressure was 0.440 MPa; these values were 90.1% and 94.6% of the fuel and oxidizer plenum total pressure, respectively, even though pressure was lost through the small diameter injector holes.
-
experimental visualization of the structure of rotating Detonation Waves in a disk shaped combustor
Journal of Propulsion and Power, 2017Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Yoshiki Kumazawa, Jumpei Fujii, Ikkoh FunakiAbstract:The rotating Detonation engine is a propulsion system that obtains thrust using continuously existing Detonation Waves. A rotating Detonation combustor usually has an annular shape that allows Detonation Waves to propagate in the circumferential direction. In this study, we used a disk-shaped rotating Detonation combustor with a combustion chamber with flat-plane glass walls to observe the structure of the phenomena. Self-luminescence, shadowgraphs, and schlieren visualization experiments were performed and compared. Results revealed that Detonation Waves were propagating in a mixture layer of three gases, fuel, oxidizer, and burned gas at 1600 to 900 m/s; Chapman-Jouguet velocity was 2376 m/s. Waves maintained a three-dimensional complicated wave shape in the disk-shaped combustion chamber with parallel-jet injectors.
-
visualization of rotating Detonation Waves in a plane combustor with a cylindrical wall injector
53rd AIAA Aerospace Sciences Meeting 2015, 2015Co-Authors: Soma Nakagami, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Ikkoh FunakiAbstract:A Rotating Detonation Engine (RDE) has higher thermal efficiency and simpler structure than a conventional gas turbine engine. Therefore, many research institutions has been investigating RDEs. Property of propagation of Detonation Waves in a RDE, however, has not been fully elucidated yet. Toward the practical use of RDEs, clarifying the propagation characteristics of Detonation Waves in RDEs is important. In the present study,we fabricated a plane RDE combustor with a cylindrical wall injector and performed visualization experiment. Propagation speed of the combustion Waves that was observed in this experiment had reached to about 1300 – 1100 m/s, that is about 55 – 45 % of Chapman Jouguet Detonation velocity.