Xingyu Su

Tsinghua University | TH · Department of Thermal Engineering

(Below is the free share link before 2024/06/13) https://authors.elsevier.com/a/1izhL2KiHiDzl

Chemical kinetics plays an important role in the direct detonation initiation (DDI) of various combustible mixtures. However, its impact on detonation dynamics has rarely been studied with detailed mechanisms. This study introduces the active subspace method to systematically explore the chemical kinetics impact on the unsteady detonation dynamics...

Considerable research has been reported on developing effective active control means to suppress oscillating combustion. The typical pressure oscillation can be divided into linear growth, transition and saturation stages. In this study, a sliding mode control strategy, consisting of a state estimate model, disturbance observers and a sliding mode...

Advanced propulsion and power-generation systems often operate under extreme conditions, where thermophysical properties of the working fluids undergo complex variations in a wide range of fluid states, where empirical cubic equations of state could yield substantial errors in density prediction. The present work develops data-driven models for acc...

Large eddy simulation (LES) combined with filtered density function (FDF), i.e., LES/FDF, is an effective approach for high-fidelity simulation of turbulent flames. In this work, LES/FDF simulations are performed for the turbulent piloted premixed methane-air flame F3 to investigate the impact of reaction-induced subgrid scalar mixing on the predic...

Chemical kinetics mechanisms are essential for understanding, analyzing, and simulating complex combustion phenomena. In this study, a Neural Ordinary Differential Equation (Neural ODE) framework is employed to optimize kinetics parameters of reaction mechanisms. Given experimental or high-cost simulated observations as training data, the proposed...

Chemical kinetic modeling is an integral part of combustion simulation, and extensive efforts have been devoted to developing high-fidelity yet computationally affordable models. Despite these efforts, modeling combustion kinetics is still challenging due to the demand for expert knowledge and high dimensional optimization against experiments. Ther...

The difference in the mixing timescale among species, i.e., differential mixing, is a combined result due to the difference in molecular diffusivity and the difference in reaction-induced scalar gradient. Being a key component for micro-mixing, incorporating differential mixing is a desirable feature for a transported probability density function (...

The modeling of scalar mixing timescale remains a primary challenge in the transported probability density function (TPDF) method. The variation of scalar mixing timescale among species, i.e., differential mixing, results from the difference in molecular diffusivity and reaction-induced scalar gradient. Nevertheless, the vast majority of TPDF studi...

A multiple neural network controller is proposed and demonstrated to suppress the pressure oscillation of the Rijke tube acoustic network. This controller consists of three modules including two separate neural networks, i.e., the neural network of controlled object that is pretrained before control and the neural network of controller that is trai...

Monitoring the dynamics processes in combustors is crucial for safe and efficient operations. However, in practice, only limited data can be obtained due to limitations in the measurable quantities, visualization window, and temporal resolution. This work proposes an approach based on neural differential equations to approximate the unknown quantit...

Combustion kinetic modeling is an integral part of combustion simulation, and extensive studies have been devoted to developing both high fidelity and computationally affordable models. Despite these efforts, modeling combustion kinetics is still challenging due to the demand for expert knowledge and optimization against experiments, as well as the...

A systematic approach is formulated for the uncertainty analysis of kinetic parameters on combustion characteristics during skeletal reduction. The active subspace method together with sensitivity analysis is first employed to identify extreme low-dimensional active subspace of input parameter space and to facilitate the construction of response su...

Monitoring the dynamics processes in combustors is crucial for safe and efficient operations. However, in practice, only limited data can be obtained due to limitations in the measurable quantities, visualization window, and temporal resolution. This work proposes an approach based on neural differential equations to approximate the unknown quantit...

Acoustics-based tweezers provide a unique toolset for contactless, label-free, and precise manipulation of bioparticles and bioanalytes. Most acoustic tweezers rely on acoustic radiation forces; however, the accompanying acoustic streaming often generates unpredictable effects due to its nonlinear nature and high sensitivity to the three-dimensiona...

Droplet microfluidics has become an indispensable tool for biomedical research and lab-on-a-chip applications owing to its unprecedented throughput, precision, and cost-effectiveness. Although droplets can be generated and screened in a high-throughput manner, the inability to label the inordinate amounts of droplets hinders identifying the individ...

For turbulent flames involving intense turbulence-chemistry interaction, quantifying the uncertainty originating from the parameters of chemical kinetics and physical models leads to a more rigorous assessment of the predictability of simulations. In the present work, a successive dimension reduction framework based on the active subspace (AS) meth...

Advances in lab-on-a-chip technologies are driven by the pursuit of programmable microscale bioreactors or fluidic processors that mimic electronic functionality, scalability, and convenience. However, few fluidic mechanisms allow for basic logic operations on rewritable fluidic paths due to cross-contamination, which leads to random interference b...