arXiv subjects

Wenwu Zhang

Publications and source records attributed to Wenwu Zhang.

6 recordsLinked to original sources

arXiv2026

Comparative Numerical Study of Film Cooling Strategies for Thermal Protection of a Kerosene-Fueled Oblique Detonation Combustor

Thermal protection remains a critical challenge for oblique detonation engines (ODEs) operating under hypersonic conditions due to the extreme heat release and compact combustor geometry associated with oblique detonation waves (ODWs). In the present study, the effectiveness of film cooling for a kerosene-air ODE combustor is numerically investigated under a flight Mach number of 10 and an altitude of 15 km. Three active cooling strategies are considered, including air film cooling, gaseous-kerosene film cooling, and liquid-kerosene mist cooling. The results show that all cooling strategies preserve stable oblique-detonation propagation and maintain the canonical wave-system structure within the investigated operating range. Air cooling produces stronger disturbances near the initiation region and triple point, resulting in enhanced downstream wave interactions and larger propulsion penalties. In contrast, fuel-based cooling induces milder disturbances and better preserves the global detonation structure. All cooling methods substantially reduce the near-wall thermal load, although their cooling characteristics differ significantly. Gaseous-kerosene film cooling exhibits a spatially periodic near-wall thermal response associated with the discrete cooling hole arrangement, while liquid-kerosene mist cooling produces a smoother near-wall temperature distribution due to enhanced two-phase mixing and phase-change heat absorption. Among the investigated strategies, mist cooling provides the best overall balance between thermal protection and propulsion performance at coolant mass ratios of 1%-3%, whereas gaseous-kerosene film cooling becomes advantageous at higher injection levels due to improved wall coverage continuity. The present results demonstrate the feasibility and potential of fuel-based film cooling for thermal management in hypersonic ODE combustors.

physics.flu-dyn↗

arXiv2026

Endwall and leading-edge film cooling of turbine blades in a hydrogen-fueled rotating detonation combustor-turbine coupled system

This study performs a three-dimensional numerical simulation of the coupled flow field in a hydrogen-air rotating detonation combustor (RDC)-turbine system to evaluate the effectiveness of different film cooling strategies for the turbine blades. The results demonstrate that combining the endwall cooling with leading-edge film cooling effectively reduces blade surface temperatures while improving turbine flow field stability and blade protection. For endwall cooling, numerical simulations compare circular and slot hole configurations. Circular holes consume less cooling air than slot holes while maintaining comparable cooling performance, making them the preferred choice. For the leading-edge film cooling, both the vertical and the vertical-inclined schemes are examined. The vertical-inclined scheme demonstrates higher cooling efficiency and improved secondary flow attachment, ensuring greater stability under the oscillatory effects of the detonation flow. Additionally, the flow fields of film-cooled turbine blades with and without the propagation of the rotating detonation wave are compared, revealing that the upstream rotating detonation flow field facilitates the downstream diffusion of secondary film cooling jets.

physics.flu-dyn↗

arXiv2026

Investigation of Mist and Air Film Cooling in a Two-Phase Rotating Detonation Combustor with Liquid Kerosene

We present a numerical investigation of kerosene droplet mist film cooling for the thermal protection of the rotating detonation combustor (RDC) and compare its performance with conventional air film cooling and combined mist/air cooling scheme. In the study, the cooling behavior of kerosene droplets injected through wall film holes is numerically examined and compared with air film cooling and a combined mist/air cooling strategy, building on a benchmark validation against flat-plate experimental data. The results show that air film cooling exhibits an optimal operating range, beyond which excessive injection degrades film stability due to strong interaction with the rotating detonation wave. In contrast, kerosene-based mist cooling forms a more persistent near-wall cooling layer, providing enhanced heat removal through phase change and exhibiting improved resistance to film separation. In mist cooling, the droplet size primarily affects the immediate downstream cooling performance, with intermediate-sized droplets offering the improved balance between evaporation rate and film continuity. A combined mist/air cooling scheme can further improve cooling efficiency and accelerate wall temperature recovery after detonation wave passage while maintaining moderate impacts on the mainstream flow. Additionally, although kerosene droplets partially participate in combustion under film hole injection, the associated thermal load does not offset the overall cooling benefit. These findings demonstrate the feasibility and advantages of kerosene-based cooling schemes for RDC thermal management.

physics.flu-dyn↗

arXiv2024

Effects of inlet and secondary flow conditions on the flow field of rotating detonation engines with film cooling

A three-dimensional simulation of the rotating detonation engine (RDE) with film cooling is conducted. The aim of this study is to analyze the fluid dynamics and heat transfer of the detonation flow field under the influence of cooling flow from the film holes. Results suggest that when the rotating detonation wave sweeps the film holes, the shape of the wave structure will deform, and the detonation products will invade and block the outflow from the film holes; however, this only occurs temporarily. The structure of the detonation wave will quickly restore to its stable form and, meanwhile, the cooling flow also recovers rapidly and provides adequate protected area on the wall surface and effective thermal protection time in a full propagation cycle of the detonation wave. A parametric analysis indicates that the effective outflow time improves with the increase of the mass flow rate of the cooling flow; on the other hand, the cooling efficiency is more significant downstream from the inlet of the combustor to the outlet. In addition, the thrust and specific impulse of the RDE are also examined under the influence of film cooling.

physics.flu-dyn↗

arXiv2023

Investigation of Multi-Stage Evaporation and Wave Multiplicity of Two-Phase Rotating Detonation Waves Fueled by Ethanol

In this study, a numerical investigation based on the Eulerian-Lagrangian model is conducted to explore a rotating detonation engine (RDE) fueled by liquid ethanol. The focus is on examining the characteristic phenomena of the two-phase rotating detonation wave (RDW) caused by droplet evaporation and varying inlet conditions. To enhance the evaporation of liquid fuel, pre-heated air is used, and both liquid and pre-vaporized ethanol are simultaneously injected. The distribution of ethanol droplets reveals an initial concentration near the injection surface and accumulation in the fuel-refill zone. Here, liquid droplets gradually evaporate after absorbing latent heat from the surrounding gas. The subsequent interactions between the evaporating droplets and the RDW vary with the droplet size. For droplets with diameters of $d_0$ = 5-15 $μ$m, after being swept by the RDW, a secondary evaporation process occurs, leading to an enlargement of the width of the reaction zone. However, the chemical reactions still predominantly take place in close proximity to the detonation front. As further increases, droplet evaporation persists in the post-detonation expansion zone over a long distance until the remaining droplets are fully evaporated and eventually burned in this region. The study also analyzes the extinction of rotating detonations and the emergence of new detonation waves resulting from local explosions and consequent shock collisions. It is demonstrated that variations in the diameter of injected droplets and inlet temperature can lead to different operating modes with varying numbers of RDWs.

physics.flu-dyn↗

arXiv2023

Structure of A Heterogeneous Two-Phase Rotating Detonation Wave with Ethanol-Hydrogen-Air Mixture

In this short Letter, the structure of a rotating detonation wave (RDW) fueled by biofuel is revealed and expounded. The simulation is carried out under an Eulerian-Lagrangian framework in which the main characteristics of the two-phase RDW are analyzed in detail. Results suggest a self-sustained rotating detonation fueled by liquid ethanol and air can be achieved with hydrogen addition for combustion enhancement, and a laminated dual-front structure of the RDW due to the effect of droplet evaporation is captured and clarified.

physics.flu-dyn↗