Investigation of Mist and Air Film Cooling in a Two-Phase Rotating Detonation Combustor with Liquid Kerosene
Pith reviewed 2026-05-10 12:46 UTC · model grok-4.3
The pith
Kerosene mist cooling creates a more persistent protective layer than air film cooling in rotating detonation combustors.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Numerical simulations demonstrate that injecting kerosene droplets as mist through wall film holes in a rotating detonation combustor produces a durable cooling film. This film provides superior heat removal via phase change and shows greater resistance to separation caused by the rotating detonation wave compared to air film cooling. Intermediate droplet sizes optimize the trade-off between rapid evaporation and sustained coverage. Combining mist with air injection improves overall cooling efficiency and accelerates post-detonation wall cooling with limited disruption to the main flow. Although some kerosene participates in combustion, the cooling benefits outweigh this effect.
What carries the argument
Kerosene mist film cooling, where wall-injected droplets evaporate to form a phase-changing protective boundary layer near the combustor wall.
If this is right
- Air film cooling has a limited operating range before excessive injection destabilizes the film due to detonation wave interactions.
- Droplet size in mist cooling primarily influences downstream cooling effectiveness, with intermediate sizes best balancing evaporation and continuity.
- The combined mist/air scheme boosts cooling efficiency and shortens recovery time for wall temperatures after detonation passage.
- Partial combustion of injected kerosene droplets occurs but does not cancel out the overall cooling advantages.
Where Pith is reading between the lines
- This mist cooling approach could support higher detonation frequencies or longer operating times in RDCs by managing wall heat loads more effectively.
- The technique might transfer to other high-heat propulsion systems such as scramjets where film stability is difficult to maintain.
- Optimizing injection locations and droplet sizes could further reduce any unwanted effects on the main combustor flow.
Load-bearing premise
The turbulence, droplet evaporation, and combustion models, which were checked only against flat-plate experiments, correctly simulate the unsteady interactions of the rotating detonation wave with the injected droplets and the developing wall film in the full combustor.
What would settle it
Wall temperature and heat transfer measurements taken inside an operating rotating detonation combustor with kerosene mist injection compared directly to air-only cases under matched conditions.
read the original abstract
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.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper presents a numerical CFD investigation of kerosene droplet mist film cooling in a two-phase rotating detonation combustor (RDC), comparing its performance to conventional air film cooling and a combined mist/air scheme. Building on flat-plate validation, it claims that kerosene mist forms a more persistent near-wall cooling layer with enhanced heat removal via phase change and greater resistance to separation under detonation wave passage; intermediate droplet sizes balance evaporation and film continuity; the combined scheme further improves efficiency and post-detonation recovery with moderate mainstream impact; and partial kerosene combustion does not negate the cooling benefit.
Significance. If the numerical predictions hold under the unsteady RDC conditions, the work would offer a concrete path toward improved thermal management in rotating detonation engines, where extreme heat loads limit durability. The identification of mist cooling's advantages in film persistence and recovery time, plus the feasibility of using the fuel itself for cooling, could influence injector and wall design in practical RDC systems.
major comments (1)
- [Abstract / Numerical Methods] Abstract and Numerical Methods: The central claims (persistent near-wall layer, improved resistance to film separation, faster post-detonation recovery) rest on the turbulence, droplet evaporation, and combustion sub-models accurately predicting unsteady droplet trajectories and film stability under periodic high-amplitude pressure pulses. These models are benchmarked only against steady flat-plate experiments; no mesh-convergence checks, turbulence-model sensitivity studies, or RDC-specific validation cases are reported. This is load-bearing for the extrapolation to the full combustor geometry.
minor comments (2)
- [Abstract] Abstract: The statement that 'droplet size primarily affects the immediate downstream cooling performance' would benefit from explicit quantification of the size range and distribution employed in the simulations.
- [Abstract] Abstract: The claim of 'moderate impacts on the mainstream flow' for the combined scheme lacks reference to specific metrics (e.g., total pressure loss or velocity deficit) that would allow direct comparison with the single-scheme cases.
Simulated Author's Rebuttal
We thank the referee for the detailed and constructive feedback on our numerical investigation of kerosene mist film cooling in a rotating detonation combustor. The comments highlight important aspects of model validation that we have addressed through revisions and additional analysis. Our point-by-point responses follow.
read point-by-point responses
-
Referee: Abstract and Numerical Methods: The central claims (persistent near-wall layer, improved resistance to film separation, faster post-detonation recovery) rest on the turbulence, droplet evaporation, and combustion sub-models accurately predicting unsteady droplet trajectories and film stability under periodic high-amplitude pressure pulses. These models are benchmarked only against steady flat-plate experiments; no mesh-convergence checks, turbulence-model sensitivity studies, or RDC-specific validation cases are reported. This is load-bearing for the extrapolation to the full combustor geometry.
Authors: We agree that the validation strategy relies primarily on steady flat-plate experiments, which is standard for film-cooling studies but limits direct assessment of unsteady RDC effects. To strengthen the manuscript, we have added a dedicated mesh-convergence study in the revised Numerical Methods section, confirming that wall temperature, film thickness, and evaporation rates are insensitive to further grid refinement beyond the reported resolution. We have also included a turbulence-model sensitivity analysis comparing the baseline k-epsilon model with an alternative SST k-omega formulation, showing that the relative performance trends between mist, air, and combined cooling remain consistent. Regarding RDC-specific validation, we have expanded the discussion to cite supporting literature on droplet trajectories and evaporation under high-amplitude pressure oscillations, arguing that the sub-models capture the dominant physics for the comparative claims made. These additions directly support the extrapolation while acknowledging the steady-to-unsteady step. revision: yes
- Direct experimental data for kerosene mist film cooling under full rotating detonation conditions, which does not currently exist in the literature and would require new dedicated experiments beyond the scope of this numerical study.
Circularity Check
No significant circularity; forward simulation with external validation
full rationale
The paper performs a forward CFD simulation study of cooling schemes in an RDC geometry. Governing equations and sub-models (turbulence, droplet evaporation, combustion) are applied after validation against independent flat-plate experiments; results on film persistence, separation resistance, and post-detonation recovery are direct outputs of those simulations rather than quantities fitted or defined from the RDC data itself. No equations reduce to their own inputs by construction, no predictions are statistically forced from fitted parameters, and no self-citation chains or uniqueness theorems are invoked as load-bearing premises. The derivation from the two-phase flow model to the reported performance comparisons is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
Reference graph
Works this paper leans on
- [1]
-
[2]
Q. Xie, H. Wen, W. Li, Z. Ji, B. Wang, P. Wolanski, Analysis of operating diagram for H2/Air rotating detonation combustors under lean fuel condition, Energy 151 (2018) 408-419
work page 2018
-
[3]
Z. Zhang, H. Xu, J. Guo, X. Ni, Z. He, Z. Duan, Q. Zheng, C. Weng, The oretical investigation on the energy conversion efficiency and performance of continuous rotating detonation ramjet engine with different types of fuels under various flight Mach numbers, Aerospace Science and Technology 163 (2025) 110336
work page 2025
-
[4]
J.Z. Ma, M.Y . Luan, Z.J. Xia, J.P. Wang, S.J. Zhang, S.B. Yao, B. Wang, Recent progress, development trends, and consideration of continuous detonation engines, AIAA Journal 58 (2020) 4976-5035
work page 2020
- [5]
-
[6]
Y . Zhu, S. Zhang, H. Chen, Y . Wu, Liquid fuels in rotating detonation engines: Advances and challenges, Physics of Fluids 36 (2024) 121305
work page 2024
-
[7]
T. Sato, K. Matsuoka, N. Itouyama, M. Yasui, K. Matsuyama, Y . Ide, K. Nakata, Y . Suzuki, R. Ishibashi, S. Suzuki, J. Kasahara, A. Kawasaki, H. Hirashima, D. Nakata, H. Eguchi, T. Takano, M. Uchiumi, T. Himeno, Y . Yahata, A. Matsuo, I. Funaki, H. Habu, S. Arakawa, J. Masuda, K. Kawahara, T. Usuki, K. Maehara, M. Shida, T. Nakao, K. Yamada, Space Flight ...
-
[8]
R. Wiggins, E. Gutmark, Dynamics of Detonation Wave –Core Combustion Interaction in a Flow-Through Rotating Detonation Combustor, AIAA Journal 64 (2026) 2065-2087
work page 2026
-
[9]
Z. Ren, J. Lu, W.G. Dettmer, Effects of cryogenic temperature on propagation of hydrogen-air rotating detonation waves, Fuel 402 (2025) 135979
work page 2025
-
[10]
F. Ladein de, H. Oh, S. Jacobs, Supersonic combustion heat flux in a rotating detonation engine, Acta Astronautica 203 (2023) 226-245
work page 2023
- [11]
-
[12]
S.W. Theuerkauf, F.R. Schauer, R. Anthony, J.L. Hoke, Experimental characterization of high-frequency heat flux in a rotating detonation engine, 53rd AIAA Aerospace Sciences Meeting, 2015
work page 2015
-
[13]
Y . Shi, Y . Zhang, X. Jin, H. Wen, B. Wang, Parameter influence and calculation model of wall heat flux in kerosene two phase rotating detonation combustor, Combustion and Flame 273 (2025) 113924
work page 2025
-
[14]
A. Roy, P. Strakey, T. Sidwell, D.H. Ferguson, Unsteady heat transfer analysis to predict combustor wall temperature in rotating detonation engine, 51st AIAA/SAE/ASEE Joint Propulsion Conference, 2015
work page 2015
-
[15]
S. Zhou, H. Ma, C. Liu, C. Zhou, D. Liu, Experimental investigation on the temperature and heat -transfer characteristics of rotating -detonation-combustor outer wall, International Journal of Hydrogen Energy 43 (2018) 21079-21089
work page 2018
-
[16]
Y . Qiu, Y . Wu, Y . Huang, Q. Li, C. Weng, Heat transfer characteristics of H2/air rotating detonation combustor, Physics of Fluids 36 (2024) 016131
work page 2024
- [17]
-
[18]
J. Hernandez-McCloskey, T.W. Teasley, D.M. Petty, S.A. Reutlinger, D.I. Pineda, Calorimeter Heat Flux Trends in NASA ’s Subscale Rotating Detonation Rocket Engine, AIAA SCITECH 2025 Forum, 2025
work page 2025
-
[19]
S. Lu, Q. Zhu, J. Gong, H. Chen, H. Ying, Experimental study on transpiration cooling with phase change in rotating detonation engine, Applied Thermal Engineering 258 (2024) 124633
work page 2024
-
[20]
K. Goto, K. Ota, A. Kawasaki, N. Itouy ama, H. Watanabe, K. Matsuoka, J. Kasahara, A. Matsuo, I. Funaki, H. Kawashima, Cylindrical rotating detonation engine with propellant injection cooling, Journal of Propulsion and Power 38 (2022) 410-420
work page 2022
-
[21]
P.H. Glaubitz, T.C. Pritschau, J.J. Betancourt , E. Gutmark, Watercooled hollow rotating detonation combustor, AIAA SCITECH 2024 Forum, 2024
work page 2024
- [22]
- [23]
-
[24]
Goldstein, Film Coolin g, in: J.P
R.J. Goldstein, Film Coolin g, in: J.P. Abraham, J.M. Gorman, W.J. Minkowycz (Eds.), Advances in Heat Transfer1971, pp. 321-379
-
[25]
Z. Tao, X. Wang, G. Xie, H. Li, Z. Zhou, Effects of structural parameters of laidback fan-shaped hole on film cooling effectiveness on convex surface, Applied Thermal Engineering 236 (2024) 121636
work page 2024
-
[26]
Y . Luo, Z. Zhou, H. Li, L. Meng, G. Xie, A comprehensive comparison of film cooling characteristics of shaped holes on the leading edge of rotating blade, Applied Thermal Engineering 257 (2024) 124484
work page 2024
-
[27]
Y . Chen, R. Wan, Z. Ke, Comparative study of film cooling performance on curved walls with various hole configurations and blowing ratios, Applied Thermal Engineering 238 (2024) 122195
work page 2024
-
[28]
B. Li, C. Liu, L. Ye, T. Zhou, F. Zhang, Evaluation of film cooling effect in multi- row hole configurations on turbine blade leading edge, Energy 309 (2024) 132908
work page 2024
- [29]
-
[30]
J. Hu, Y . Zhang, J. Zhang, X. Kong, M. Zhu, J. Zhu, Numerical investigation of flow and heat transfer on turbine guide vane leading edge slot film cooling, Energy 309 (2024) 133116
work page 2024
-
[31]
S. Wang, W. Zeng, B. Sun, Q. Xu, Q. Du, J. Zhu, Application and performance study of low-stress film cooling holes on the guide vane, International Journal of Heat and Mass Transfer 256 (2026) 128045
work page 2026
-
[32]
J. Yu, S. Yao, J. Li, Y . Huang, C. Guo, W. Zhang, Effects of inlet and secondary flow conditions on the flow field of rotating detonation engines with film cooling, International Journal of Hydrogen Energy 48 (2023) 9082-9094
work page 2023
-
[33]
J. Yu, S. Yao, J. Li, J. Li, Y . Lei, R. Wang, W. Zhang, Experimental investigation of the hydrogen-air rotating detonation engine with cat -ear-shaped film cooling holes, International Journal of Hydrogen Energy 89 (2024) 1454-1465
work page 2024
-
[34]
J. Tian, S. Zhang, X. Tan, F. Zhu, Z. Fan, J. Li, W. Hao, Numerical investigation of annular slit film cooli ng for thermal protection in rotating detonation combustors, Aerospace Science and Technology 168 (2026)
work page 2026
-
[35]
J. Tian, Y . Wang, J. Zhang, X. Tan, Numerical investigation on flow and film cooling characteristics of coolant injection in rotating detonation combustor, Aerospace Science and Technology 122 (2022) 107379
work page 2022
-
[36]
S. Ramanagar Sridhara, A. Andreini, M.D. Polanka, M.D. Bohon, The impact of film cooling on the heat release within a rotating detonation combustor, Applications in Energy and Combustion Science 20 (2024) 100300
work page 2024
-
[37]
R. Li, J. Xu, H. Lv, D. Lv, J. Song, Numerical investigations of the nozzle performance for a rocket -based rotating detonation engine with film cooling, Aerospace Science and Technology 136 (2023) 108221
work page 2023
-
[38]
Y . Zhou, S. Yao, J. Yu, W. Qian, P. Wang, W. Zhang, Endwall and leading -edge film cooling of turbine blades in a hydrogen -fueled rotating detonation 26 combustor–turbine coupled system, Energy 335 (2025) 138307
work page 2025
-
[39]
Y . Liu, T. Zhao, C. Wen, F. Guo, J. Zhu, Characteristics analysis for turbine film cooling under rotating detonation combustion, Applied Thermal Engineering 269 (2025) 126054
work page 2025
-
[40]
S.R. Shine, S.S. Nidhi, Review on film cooling of liquid rocket engines, Propulsion and Power Research 7 (2018) 1-18. [41] C. Kirchberger, G. Schlieben, A. Hupfer, H.-P. Kau, S. Soller, P. Martin. Investigation on Film Cooling in a Kerosene/GOX Combustion Chamber. In: editor^editors. 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit; 2009. p
work page 2018
-
[41]
G. Schlieben, C.U. Kirchb erger, O.J. Haidn, C. Höglauer, B. Kniesner, O. Knab, Experimental and Numerical Film Cooling Investigations in a GOX/ Kerosene Rocket Combustion Chamber, 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2014
work page 2014
-
[42]
T. Wang, X. Li, Mist film cooling simulation at gas turbine operating conditions, International Journal of Heat and Mass Transfer 51 (2008) 5305-5317
work page 2008
-
[43]
P. Biswal, M.R. P, C. Balaji, Research advances on mist assisted impingement and film cooling o f turbine blades, International Journal of Heat and Mass Transfer 232 (2024) 125907
work page 2024
-
[44]
X. Li, T. Wang, Simulation of Film Cooling Enhancement With Mist Injection, Journal of Heat Transfer 128 (2005) 509-519
work page 2005
-
[45]
W. Perkowski, A. Bilar, M. Augustyn, M. Kawalec, Air -breathing rotating detonation engine supplied with liquid kerosene: propulsive performance and combustion stability, Shock Waves 34 (2024) 181–192
work page 2024
-
[46]
H.L. Meng, Q. Xiao, W.K. Feng, M.L. Wu, X.P. Han, F. Wang, C.S. Weng, Q. Zheng, Air-breathing rotating detonation fueled by liquid kerosene in cavity-based annular combustor, Aerospace Science and Technology 122 (2022) 107407
work page 2022
-
[47]
C. Yan, J. Zhao, Y . Tong, B. Wang, C. Shu, W. Nie, W. Lin, Formation and Evolution of the Numerical Air-Breathing Rotating Detonation Fueled by C12H23, Combustion Science and Technology 197 (2025) 276-309
work page 2025
- [48]
- [49]
-
[50]
B. Franzelli, E. Riber, M. Sanjosé, T. Poinsot, A two -step chemical scheme for kerosene-air premixed flames, Combustion and Flame 157 (2010) 1364-1373
work page 2010
- [51]
- [52]
-
[53]
Z. Ren, Y . Sun, B. Wang, Propagation behaviors of the rotating detonation wave in kerosene–air two-phase mixtures with wide equivalence ratios, Flow, Turbulence and Combustion 110 (2022) 735–753. 27
work page 2022
-
[54]
Z. Luan, J. Liu, Y . Huang, S. Gao, Z. Sun, The interaction mechanism between detonation wave and liquid kerosene, Physics of Fluids 37 (2025) 087131
work page 2025
-
[55]
W. Cao, Q. Liu, F. Wang, C. Weng, Effects of the droplet size and engine size on two-phase kerosene/air rotating detonation engines in flight operation conditions, Acta Astronautica 223 (2024) 108-118
work page 2024
-
[56]
Z. Ren, L. Zheng, Numerical study on rotating detonation stability in two -phase kerosene-air mixture, Combustion and Flame 231 (2021) 111484
work page 2021
-
[57]
T. Huo, P. Su, X. Du, L. Li, R. Zhang, L. Zhou, H. Zhang, An experimental investigation of air, mist/air, and steam film cooling on a flat plate with single- and double-row holes, Experimental Thermal and Fluid Science 169 (2025) 111559
work page 2025
-
[58]
S. Gordon, B.J. McBride, Computer program for calculation of complex chemical equilibrium compositions and applications. Part 1: Analysis, 1994
work page 1994
- [59]
-
[60]
Z. Jiao, K. Wang, Q. Xiao, Y . Zhang, W. Fan, Characteristic velocity analysis of the total pressure gain of rotating detonation combu stors, Proceedings of the Combustion Institute 40 (2024) 105626
work page 2024
- [61]
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.