2011-2016, University of Florida, Doctor of Philosophy
2008-2010, University of Colorado at Boulder, Master of Science
2004-2008, University of Science and Technology of China, Bachelor of Science

2026-now, Shanghai Jiao Tong University, Associate Professor (Tenured)
2019-2025, Shanghai Jiao Tong University, Associate Professor (Tenure-track)
2016-2018, The Hong Kong Polytechnic University, Post-doc

Vortex is the "sinew and muscle" of fluid motion, and its essence is the interaction of forces and the transport of momentum. The dynamics of vortex is the source of many unsteady and unstable flow phenomena, and is also an essential element of turbulence. Presently, a prevalent challenge encountered in developing different kinds of engines is combustion instability, which is a complex mechanism involving the interactions among spray and atomization, chemical reaction, thermofluid, and even sound waves. To this end, my primary research interest is applying vortex dynamical analysis as well as experimental and numerical approaches to understand the flow and flame instabilities associated with unsteady combustion. Flow and flame control techniques are developed to suppress the source of instabilities, thereby improving combustion stability and performance. These will be achieved via the following research thrusts:

Fundamental study
1. Vortex dynamics
2. Flame dynamics
3. Droplet dynamics

Application
1. Combustion instability
2. Combustion and flow control

2026-2029, NSFC 52576131 "Investigation on the instability mechanisms and control of the shear layers in swirling flames", principle investigator
2021-2024, NSFC 12072194 "Investigation on the aerodynamical mechanism of binary droplet collision in air crossflow", principle investigator
2021-2023, NSFC 52006139 "Investigation on the vortex breakdown mechanism in swirling flames based on high spatial-temporal-resolved laser diagnostics", principle investigator
2021-2024, NSFC 92041001 "Multi-physics field measurement of turbulent two-phase combustion and study on combustion evolution for aeroengine combustors", sub-project principle investigator
2020-2023, STCSM 20YF1420600 "Characterization and vortex-dynamical mechanism of air-blast atomization induced by synthetic jet", principle investigator
2017-2019, HKPolyU G-YBXN, "Hypergolic Ignition Induced by Propellant Droplet Collision", core participant
2017-2018, GRF PolyU 152651/16E, "Experimental and Numerical Investigation on the Collision of Binary Droplets of Shear-Thinning Fluids in Atmospheric Air", core participant

Journal papers

(2026)
[56] A. Mardani, H. Kim, S. Oh, K.C. Kim, X. Xia, and F. Qi, Experimental investigation of an ammonia-hydrogen-methane non-premixed high swirl model combustor for preheated and diluted air regime, International Journal of Hydrogen Energy 207, 153430 (2026).
[55] G. Wang, M. Gu, L. Xu, S. Lai, X. Xia, F. Qi, Advances in laser diagnostics for swirl combustion: current progress and future directions, Experimental Thermal and Fluid Science 173, 111666 (2026).
[54] L. Li, X. Tian, H. Xiao, S. Yin, Z. Feng, L. Xu, S. Lai, M. Gu, G. Wang, X. Xia, and F. Qi, Experimental investigation on the transition dynamics of stratified and merged flames in a dual-stage swirl combustor, Aerospace Science and Technology, 168, 111094 (2026).
(2025)
[53] Q. Wang, S. Lai, Y. Ren, F. Qi, and X. Xia*, Combined Reynolds-vorticity transport analysis of the shear layers in a premixed swirling flame, Journal of Fluid Mechanics 1006, A20 (2025). (JFM cover)
[52] X. Xia, Y. Chi, and P. Zhang, Scaling law in the inviscid coalescence of unequal-size droplets, Journal of Fluid Mechanics 1010, R2 (2025).
[51] X. Xia*, J. Deng, T. Yang, L. Xu*, A. Mardani, P. Zhang, and D. Zhao, Single-snapshot-based dynamical mode prediction of a flickering flame via a Fourier-neural-operator network, Applications in Energy and Combustion Science 24, 100380 (2025).
[50] C. Chu, Y. Zhang, Y. Chen, Y. Bai, F. Qi, and X. Xia*, Numerical investigation of the unsteady drag on a liquid droplet in a laminar airflow, Proceedings of the Combustion Institute 41, 105947 (2025).
[49] X. Xia* and L. Shangguan, Reduced-order aerodynamic model of a starting plate with discrete-vortex merging, Frontiers in Physics 13, 1632903 (2025).
[48] B. Yu, T. Chen, D. Liu, Y. Yang, G. Wang, L. Xu, X. Xia*, and F. Qi*, Spray and flow field characteristics of a five-injector lean premixed prevaporized model combustor, Journal of Thermal Science 34, 2262–2273 (2025).
[47] Z. Liu, L. Xu, L. Yang, X. Xia, G. Wang, and F. Qi, Frequency transition in thermoacoustic oscillations of a lean premixed swirl burner, Energy 335, 138308 (2025).
[46] Y. Chen, M. Chen, X. Xia, J.C. Hermanson, and F. Qi, Efficient Monte Carlo simulations of coagulation based on weighted particle strategies, Advanced Powder Technology 36, 105004 (2025).
[45] Z. Feng, X. Tian, L. Xu, X. Xia, and F. Qi, Experimental investigation of pure hydrogen flame in a matrix micro-mixing combustor, Aerospace 12, 464 (2025).
[44] 于博文, 陈涛, 刘德文, 夏溪, 王国情, 徐亮亮, 齐飞, 射流扩散火焰闪烁模态及频率特性的实验研究, 燃烧科学与技术 31, 62-73 (2025).
(2024)
[43] Y. Chen, M. Chen, Xi Xia*, J.C. Hermanson, and F. Qi, Refining the reconstruction-based Monte Carlo methods for solving breakage population balance equation, Powder Technology 442, 119870 (2024).
[42] Y. Ren, Q. Wang, Y. Peng, L. Xu, X. Xia*, F. Qi*, Strong and weak interactions of a V-shaped premixed swirling flame with outer vortex rings, Combustion and Flame 270, 113760 (2024).
[41] Y. Yang, H. Zhang, L. Li, M. Gu, X. Xia*, and F. Qi, Formation of a blue whirl controlled by tangential and radial airflows, Combustion and Flame 259, 113200 (2024).
[40] Y. Yang, H. Zhang, L. Li, M. Gu, X. Xia*, and F. Qi, How does blue ring form in a blue whirl: an experimental study, Proceedings of the Combustion Institute 40, 105772 (2024).
[39] H. Qi, X. Tian, Z. Feng, Y. Yang, D. Liu, Q. Wang, G. Wang, L. Xu*, and X. Xia*, Investigation of longitudinal self-excited combustion instability in a micromix hydrogen combustor, Proceedings of the Combustion Institute 40, 105762 (2024).
[38] H. Zhang, Y. Yang, L. Li, Y. Peng, X. Xia*, and F. Qi, Frequency jump of a flickering buoyant jet diffusion flame influenced by ambient coflow, Proceedings of the Combustion Institute 40, 105321 (2024).
[37] H. Zhang, Y. Yang, L. Li, Y. Lin, F. Qi, and X. Xia*, Experimental study on the flickering and pinch-off of jet diffusion flames, Physical Review Fluids 9, 113202 (2024).
[36] Y. Ren, Q. Wang, Y. Guan, X. Xia*, and F. Qi*, Complex network analysis of a premixed swirling flame influenced by precessing vortex core, Physics of Fluids 36, 087123 (2024).
[35] J. Zheng, Y. Guan, L. Xu, X. Xia, L.K.B. Li, and F. Qi, Scale-free topology of vortical networks in a turbulent thermoacoustic system, Physical Review Fluids 9, 033202 (2024).
[34] J. Zheng, L. Li, G. Wang, X. Xia, L. Xu, and F. Qi, Nonlinear response of conical flame to dual-frequency excitation, Applications in Energy and Combustion Science 18, 100266 (2024).
[33] D. Liu, Z. Feng, X. Tian, L. Xu, M. Gu, Y. Lin, Xi Xia, and F. Qi, Investigation of flame response in a swirling micromix hydrogen-methane combustor, Journal of Engineering for Gas Turbines and Power 146, 121027 (2024).
[32] S. Yin, Z. Fei, L. Li, S. Wang, L. Xu, Y. Lin, S. Wang, J. Ye, Xi Xia, M. Gu, and F. Qi, Investigation of 10 kHz filtered Rayleigh scattering and CH2O planar laser-induced fluorescence measurement in two-stage swirl combustor, Chinese Journal of Chemical Physics 37, 162-170 (2024).
[31] M. Wang, C. Fu, X. Wang, K. Liu, S. Meng, M. Zhang, J. Yu, Xi Xia, and Y. Gao, Experimental Investigation on the Symmetry and Stabilization of Ethanol Spray Swirling Flames Utilizing Simultaneous PIV/OH-PLIF Measurements, Symmetry 16, 205 (2024).
(2023)
[30] X. Xia* and K. Mohseni, A theory on leading-edge vortex stabilization by spanwise flow, Journal of Fluid Mechanics 970, R1 (2023).
[29] Y. Yang, H. Zhang, X. Xia*, P. Zhang, and F. Qi, An experimental study of the blue whirl onset, Proceedings of the Combustion Institute 39, 3705-3714 (2023).
[28] Q. Wang, Y. Ren, M. Gu, B. Yu, X. Feng, F. Qi, and X. Xia*, Influence of inner shear layer on the emergence of central recirculation zone in a V-shaped premixed swirling flame, Physics of Fluids 35, 107129 (2023).
[27] Y. Chen, J. Ding, X. Xia*, P. Weng*, and F. Qi, A unified Monte Carlo approach for population balance simulation of particle coagulation and breakage, Chemical Engineering Science 281, 119190 (2023).
[26] 张昊东, 杨溢凡, 李林烨, 夏溪*, 齐飞*, 射流扩散火焰闪烁模态及频率特性的实验研究, 力学学报 55, 2813-2824 (2023).
(2022)
[25] Y. Chen, J. Ding, X. Xia*, and P. Weng*, Reconstruction-based Monte Carlo method for accurate and efficient breakage simulation, Powder Technology 401, 117318 (2022).
[24] S. Wang, J. Zheng, L. Xu, Q. An, X. Han, C. Zhang, L. Li*, X. Xia*, and F. Qi, Experimental investigation of the helical mode in a stratified swirling flame, Combustion and Flame 244, 112268 (2022).
[23] S. Wang, J. Zheng, L. Li, Z. Yang, X. Xia, C. Fu, Y. Gao, X. Liu, X. Han, C. Zhang, and F. Qi, Evolution characteristics of 3D vortex structures in stratified swirling flames studied by dual-plane stereoscopic PIV, Combustion and Flame 237, 111874 (2022).
[22] S. Wang, J. Zheng, L. Li, X. Xia, X. Han, C. Zhang, F. Qi, and Z. Yang, Extensional study of optical-flow enhanced hybrid PIV method for dual-plane stereoscopic PIV measurement, Measurement Science and Technology 33, 095012 (2022).
[21] 吴昀辉, 傅宸, 高怡, 王晓阳, 夏溪, 声激励下旋流钝体火焰的非线性响应实验, 航空动力学报 37, 1872-1885 (2022).
(2021)
[20] X. Xia, C. Fu, Y. Yang, X. Yang, Y. Gao*, and F. Qi*, Vortex formation and frequency tuning of periodically-excited jet diffusion flames, Proceedings of the Combustion Institute 38, 2067-2074 (2021).
[19] H. Zhang, X. Xia*, and Y. Gao*, Instability transition of a jet diffusion flame in quiescent environment, Proceedings of the Combustion Institute 38, 4971-4978 (2021).
[18] G. Wang, X. Liu, X. Xia*, S. Wang, and F. Qi*, Dynamics of periodically-excited vortices in swirling flames, Proceedings of the Combustion Institute 38, 6183-6191 (2021).
[17] G. Wang, T. F. Guiberti, X. Xia, L. Li, X. Liu, W. L. Roberts, and F. Qi, Decomposition of swirling flame transfer function in the complex space, Combustion and Flame 228, 29-41 (2021).
[16] C. Zhang, Z. Zhang, K. Wu, X. Xia, and X. Fan, Atomization of misaligned impinging liquid jets, Physics of Fluids 33, 093311 (2021). (Featured article & Scilight)
(2020)
[15] C. He, X. Xia, and P. Zhang, Vortex-dynamical implications of nonmonotonic viscous dissipation of off-center droplet bouncing, Physics of Fluids 32, 032004 (2020). (Featured article)
[14] Z. Li, C. Fu, Y. Gao, X. Xia, W. Yuan, D. Ju, and F. Qi, Investigation on spray and combustion characteristics of boron/ethanol nanofuel utilizing 50 kHz repetition rate high-speed laser measurements, Fuel 287, 119562 (2020).
(2019)
[13] X. Xia, C. He, and P. Zhang, Universality in the viscous-to-inertial coalescence of liquid droplets, PNAS 116, 23467-23472 (2019).
[12] T. Yang, X. Xia, and P. Zhang, Vortex-dynamical interpretation of anti-phase and in-phase flickering of dual buoyant diffusion flames, Physical Review Fluids 4, 053202 (2019).
[11] C. He, X. Xia, and P. Zhang, Non-monotonic viscous dissipation of bouncing droplets undergoing off-center collision, Physics of Fluids 31, 052004 (2019).
[10] X. Zhu, X. Xia, and P. Zhang, Stability of Buoyant Inverse Diffusion Methane Flames with Confinement Effects, Combustion Science and Technology 191, (2019).
(2018之前)
[9] X. Xia and P. Zhang, A vortex-dynamical scaling theory for flickering buoyant diffusion flames, Journal of Fluid Mechanics 855, 1156-1169 (2018).
[8] X. Xia and K. Mohseni, Transitional region of a round synthetic jet, Physical Review Fluids 3, 011901(R) (2018).
[7] X. Zhu#, X. Xia#, and P. Zhang, Near-field flow stability of buoyant methane/air inverse diffusion flames, Combustion and Flame 191, 66-75 (2018).
[6] X. Xia, C. He, D. Yu, J. Zhao, and P. Zhang, Vortex-ring-induced internal mixing upon the coalescence of initially stationary droplets, Physical Review Fluids 2, 113607 (2017).
[5] X. Xia and K. Mohseni, Unsteady aerodynamics and vortex-sheet formation of a two-dimensional airfoil, Journal of Fluid Mechanics 830, 439-478 (2017).
[4] X. Xia and K. Mohseni, Flow characterization and modeling of strong round synthetic jets in crossflow, AIAA Journal 55, 389-402 (2017).
[3] X. Xia and K. Mohseni, Parameter governing the far-field features of round jets, Physical Review Fluids 1, 062401(R) (2016).
[2] X. Xia and K. Mohseni, Far-field momentum flux of high-frequency axisymmetric synthetic jets, Physics of Fluids 27, 115101 (2015).
[1] X. Xia and K. Mohseni, Lift evaluation of a two-dimensional pitching flat plate, Physics of Fluids 25, 091901 (2013).

Undergraduate:
Combustion, 2021-present
Introduction to Engineering, 2019-2022

Graduate:
Advanced Combustion Theory (English course), 2021-present

2021 Young Investigator of the Asia-Pacific Conference on Combustion
2020 Shanghai High-level Young Talent
2016 Student Research Award (University of Florida)