Ming Jia

• PhD
• Professor at Dalian University of Technology

With the utilization of new practical fuels in engines, including mixed fuels, the droplet evaporation model may not adequately describe the phenomenon of the multi-component fuel droplets undergoing boiling at high ambient temperatures due to the large difference in the boiling points between the different components. Therefore, the construction o...

Biodiesel and n-butanol, as popular alternative fuels, can be used in advanced reactivity-controlled compression ignition (RCCI) engines for efficient and clean combustion. However, the complex interactions between n-butanol and biodiesel, as well as the best combustion schemes at different loads, remain poorly understood. Given this, the objective...

The application of ammonia as an alternative carbon-free fuel has attracted increasing attention. In this paper, the effects and mechanisms of ammonia energy ratio (AER) and polyoxymethylene dimethyl ethers (PODE) injection timing on the combustion and emissions characteristics of a PODE/ammonia RCCI engine are investigated by both experimental and...

In the present study, molecular dynamics simulations are conducted to investigate the sub/supercritical phase change of alcohol (methanol and ethanol)/n-heptane mixtures. Obvious quasi-azeotropy and preferential evaporation phenomena appear for ethanol/n-heptane mixtures under subcritical conditions, and the quasiazeotropy intensity is significantl...

10 Both the injection parameters and injector layouts of a methanol/diesel dual-fuel direct injection 11 compression ignition engine operated at low loads were optimized using the genetic algorithm to 12 achieve high fuel efficiency and low emissions simultaneously. The important parameters were 13 identified according to the sensitivity analysis,...

As one of the most popular synthetic fuels (E-fuels), Polyoxymethylene dimethyl ethers(PODE X) have garnered significant attention among researchers in the compression ignition engine field. This work aims to provide an exhaustive analysis of the combustion characteristics of PODE 3 , which typically constitutes the primary component of PODE X. Thi...

Methylcyclohexane (MCH) is the simplest alkylated cyclohexane, and has been widely employed in surrogate models to represent the cycloalkanes in real fuels. Thus, extensive experimental and kinetic modeling studies have been performed to understanding the combustion chemistry of MCH. However, through a detailed literature analysis, there still lack...

This study employs molecular dynamics simulations to study the phase change behavior of liquid ammonia within a hydrogen-rich environment under varying ambient pressure conditions, with a primary focus on the characteristics of the gas-liquid interface and the dissolution effect of ambient gas. The results indicate that the substantial cooling effe...

The Kelvin-Helmholtz Rayleigh-Taylor (KH-RT) breakup model has been extensively utilized in fuel spray simulations. In the KH-RT model, there are five important empirical model parameters, which need to be calibrated carefully for different fuels under various operating conditions. In this work, the global sensitivity analysis of the model constant...

Supercritical water gasification (SCWG) coupled with solar energy systems is a new biomass gasification technology developed in recent decades. However, conventional solar-powered biomass gasification technology has intermittent operation issues and involves multi-variable characteristics, strong coupling, and nonlinearity. To solve the above probl...

Focusing on the gasoline compression ignition (GCI) combustion mode, the operating parameters, fuel composition, and piston bowl geometry were collaboratively optimized at high loads to improve engine performance. A meliorative genetic algorithm coupled with a three-dimensional computational fluid dynamics (CFD) program was adopted as the optimizat...

This study aims to investigate the control mechanism of fuel properties and intake temperature (Tin) on the low-temperature polyoxymethylene dimethyl ethers (PODEn)/gasoline combustion to maximize the advantages of PODEn in enhancing engine performance. To achieve this goal, two representative combustion modes of partially premixed combustion (PPC)...

The uncertainties existing in the parameters of chemical kinetic models have a non-negligible influence on the model predictions. It is necessary to conduct a quantitative uncertainty analysis to explore the influence of each parameter on chemical mechanism predictions. To comprehensively consider the effect of the uncertainties of reaction rate pa...

Polyoxymethylene dimethyl ethers (abbreviated as PODEn or OMEn) is a type of e-fuel with the structure CH3O(CH2O)nCH3. The carbon neutrality throughout its life cycle makes PODEn an attractive alternative to fossil fuels. Burning PODEn instead of fossil fuel can significantly reduce carbon monoxide, carbon dioxide, hydrocarbon, and especially parti...

The thermal wall function method offers an effective pathway for modeling heat transfer in engines. This paper re-examined the traditional construction method of the thermal wall function and improved it by correcting the integration scheme in the boundary layer, then an enhanced heat transfer model was introduced. Since the heat release from the c...

Progressively stricter pollutant emission targets in international agreements have shifted the focus of combustion research to low carbon fuels. Ammonia is recognized as one of the promising energy vectors for next-generation power production. Due to the low flame speed and high auto-ignition temperature, ammonia is often burned with a high reactiv...

In spray simulations, uncertainties in the collision incidence predictions always exist for droplet collision models under the discrete droplet model (DDM) framework. In this study, Beer's law, which is used for electromagnetic radiation and light absorption, was improved to evaluate the accuracy of droplet collision models by eliminating the shado...

The aim of current research is to develop an enhanced heat transfer model to accurately predict the heat flux through the cylinder walls during the working process of internal combustion engines operated under different loads and combustion modes. Two enhanced models, i.e., the unsteady model and the steady convective contribution (SCC) model were...

Higher alcohols are potential surrogate fuels for engines because of their large cetane number and multiple sources from non-food crops. The detailed chemical mechanisms of higher alcohols are usually constructed based on reaction rate rules. In the present study, reaction rate rules are utilized to construct the skeletal mechanisms of the linear a...

A single-fuel dimethyl ether reactivity-controlled compression ignition engine system was established by integrating dimethyl ether/steam on-board reforming. For the dimethyl ether reforming reactivity-controlled compression ignition engine system, the product of dimethyl ether reforming (including the generated syngas and unreacted dimethyl ether)...

In dual-fuel engines, diesel is typically used to initiate the ignition of methanol, resulting in a turbulent spray flame. However, the lack of skeletal or reduced mechanisms for methanol/n-heptane blends limits the further research of dual-fuel combustion. Therefore, a skeletal methanol/n-heptane mechanism including 52 species and 182 reactions wa...

A boiling model was proposed and coupled with a quasi-dimensional evaporation model to simulate the vaporization of a bi-component droplet under wide-temperature environments. Different from previous droplet evaporation models, the transition between droplet evaporation and boiling was especially focused on in this study. In the boiling model, the...

Predictive models based on graph neural network (GNN) have attracted increasing interest in quantitative structure-property relation (QSPR) modeling of organic species including biofuel components in recent years. For the task of property prediction of biofuel-relevant species, the present work applies the Directed Message Passing Neural Network (D...

As a major chemical class of fossil fuels, mono-alkylated cyclohexanes are frequently employed to construct the surrogate fuels of fossil fuels. Much effort has been made to study the oxidation behavior of mono-alkylated cyclohexanes, but reduced/skeletal mechanisms suitable for multi-dimensional combustion simulations are still scarce. In this wor...

Molecular dynamics (MD) simulation is a powerful tool to reveal the microscopic characteristics of supercritical transitions. However, the accuracy of MD depends strongly on the potential model that describes the interaction forces between atoms. In this study, four commonly used potential models for long-chain n-alkanes in MD simulations are evalu...

The application of lean-burn technology in engines that aims to meet the low-carbon combustion promotes the development of turbulent jet ignition (TJI) system. A turbulent jet ignition system has great potential in improving ignition stability and accelerating flame propagation. In this study, a numerical investigation of the turbulent injection ig...

The application of artificial neural network (ANN) models in replacement of numerical integration solvers for ordinary differential equations (ODE) has attracted increasing interest in recent years owing to its high computational speed potential and approximation capabilities. However, regarding its application for the calculation of chemical kinet...

Due to the specific prediction requirements in combustion simulations, the reduced chemical mechanism developed focusing on particular applications is usually needed. A systematic method for chemical mechanism reduction orientated toward specific applications is proposed in this work. The reduction process is divided into two parts for large-molecu...

A reliable reduced chemical model is crucial for the design and optimization of advanced combustion systems. At present, reduced mechanisms are usually obtained by directly reducing detailed mechanisms. Due to the limitations of computational methods and measurement techniques, the construction of detailed mechanisms for high-carbon fuels is still...

Through the integration of three-dimensional computational fluid dynamics (CFD) simulation and genetic algorithm, the operating parameters and fuel composition of a gasoline compression ignition (GCI) engine were simultaneously explored in the full load range. The blends of n-heptane, iso-octane, and toluene were utilized as the substitute for real...

Water injection (WI) is a promising technology in diesel engines. However, the joint effects of WI and fuel injection strategy have not been investigated well. Furthermore, the comparison between WI and exhaust gas recirculation (EGR) requires further clarification. This study aims to identify the optimal way of WI and its benefits for a high-load...

A new and efficient sectional method is developed and presented in this work. This new method, namely hybrid sectional moment projection method, seeks to combine the techniques of moment projection method and sectional method in a flexible and accurate way. It adopts the concept of weighted particles from moment projection method to handle the part...

The potential of reactivity controlled compression ignition (RCCI) combustion fueled with hydrogen and diesel (i.e. hydrogen/diesel RCCI) was evaluated using multi-dimensional simulations embedded with a reduced chemical mechanism. In hydrogen/diesel RCCI, the premixed hydrogen is ignited by the diesel, which is directly injected into the cylinder...

An optimized decoupling physical–chemical surrogate (DPCS) model was carried out to formulate different diesel surrogates effectively. In the optimized DPCS model, the physical candidates of ten components and the chemical candidates of four components are coupled by the rule of hydrocarbon type to match the physical–chemical properties of diesel f...

Turbulent jet ignition (TJI) is a promising technology that enables engines to operate stably at ultra-lean-burn conditions for improved thermal efficiency. In the present work, TJI of an ultra-lean methane/air mixture (excessive air ratio λ = 2.0) under an engine-like condition (temperature of 900 K and pressure of 5.8 MPa) was numerically studied...

Due to high oxygen content and lack of CC bond, polyoxymethylene dimethyl ethers (PODEn) have become desired fuel additives to simultaneously reduce nitrogen oxides (NOx) and soot emissions. However, there is a vacancy of reduced reaction mechanisms to describe the long-chain PODEn (n>3) combustion for engine simulations. This study aims at the con...

Focusing on the dual-mode dual-fuel (DMDF) combustion concept, a combined optimization of the piston bowl geometry with the fuel injection strategy was conducted at various loads. An improved genetic algorithm was introduced in this study, which is superior in searching for the global optimal solutions. The optimal piston bowl shape coupled with th...

Turbulent multiphase combustion plays an important role in both nature (e.g., volcanos and pool fires) and industry (e.g., industrial furnaces, aeroengines, and internal combustion engines). It is a highly complex multiscale and multi-physicochemical process in which interactions between the dispersed and continuous phases, phase change, droplet co...

To solve the challenges of the high heat release rate of partially premixed combustion (PPC) and low combustion efficiency of reactivity-controlled compression ignition (RCCI), RCCI with reverse reactivity stratification (R-RCCI) fueled with gasoline and polyoxymethylene dimethyl ethers (PODEn) was investigated at low and medium loads in a light-du...

To improve the trade-off between thermal efficiency and peak heat release rate (HRR) of partially premixed combustion (PPC) and the combustion efficiency of reactivity-controlled compression ignition (RCCI), the combustion mode with premixed high-reactivity fuel and direct-injection (DI) low-reactivity fuel, called RCCI with reverse reactivity stra...

For n-butanol/diesel dual-fuel combustion, there are two different implementations, i.e., dual direct injection (DI²) strategy and reactivity controlled compression ignition (RCCI) strategy. The DI² strategy is a novel combustion concept, which is expected to address the inefficient combustion and high pressure rise rate dilemmas raised by RCCI. In...

In response to the stringent emission regulations, artificial neural network (ANN) coupled with genetic algorithm (GA) is employed to optimize a novel internal combustion engine strategy named direct dual fuel stratification (DDFS). An enhanced ANN model is introduced to improve the accuracy and stability of predictions. Compared to the conventiona...

In this paper, the boiling vaporization and breakup of single droplets of n-butanol, n-hexadecane and their binary mixtures with 10-50 w.t.% n-butanol have been studied. The experiments of droplet evaporation with an elevated ambient temperature range of 537-609 K were conducted through the pendant drop method and high-speed camera technology. The...

Focusing on the spray simulation in engines using the Lagrangian-Drop Eulerian-Fluid (LDEF) approach, a new hybrid stochastic/trajectory (HST) droplet collision model with the improved collision frequency, the redivided collision cell, and an updated method for selection of the candidate collision pairs was developed in this study. The stochastic m...

Homogeneous nucleation and bubble evolution inside a fuel droplet trigger the occurrence of flash boiling, which shows a high potential to improve the droplet evaporation. To understand the bubble dynamic characteristics, an analytical study on homogeneous nucleation and bubble evolution has been performed, based on the flash boiling model proposed...

To investigate the oxidation and combustion performance of practical fuels, surrogate fuels including various types of fuels are usually introduced. The unique functional groups of different fuels dominate the fuel oxidation behaviors of different fuels, thus it is crucial to take account of the impact of fuel function groups for the development of...

This study focuses on investigating the combined effects of fuel reactivity, equivalence ratio (φ)-sensitivity, and intake temperature (Tin) on the performance of low-temperature gasoline combustion. To achieve this goal, the combustion characteristics of pure gasoline and gasoline/polyoxymethylene dimethyl ethers (PODEn) blend with the volume frac...

The widely used droplet-droplet collision outcome model distinguishing stretching separation (SS) and fast coalescence (FC) (named SS/FC model) proposed by Jiang et al. [J. Fluid Mech. 234, 171 (1992)] is corrected and improved in this study. By re-deriving the momentum conservation, the correct mathematical expression of the tangential velocity al...

The emphasis of this paper is to explore the gas-liquid interface characteristics of binary-component n-alkane fuels composed of n-heptane and n-dodecane at sub/supercritical nitrogen environments, and examine the vapor-liquid equilibrium (VLE) assumption adopted in the continuum-based vaporization models using the molecular dynamics simulation. In...

Heat transfer characteristics of water spray cooling with n-butanol additive were experimentally studied in this paper. The results indicated that adding n-butanol can effectively enhance the heat dissipation and control the surface temperature. The optimal concentration of n-butanol corresponding to the best heat transfer performance is 0.5 vol%....

In the present study, spray cooling heat transfer characteristics were numerically investigated under the heat flux ranging from 50 to 170 W/cm². Effect of nozzle height and spray pressure was also studied in order to reveal the microscopic mechanisms of the heat transfer enhancement from single-phase to nucleate boiling regions. A two-phase flow h...

A practical reaction model for the formation and oxidation of polycyclic aromatic hydrocarbons (PAHs) up to coronene (A7) was developed focusing on two diesel surrogate fuels, i.e., a single-component surrogate including n-heptane and a multi-component surrogate including iso-octane, n-decane, methylcyclohexane, and toluene, for engine simulations....

The diesel/gasoline dual-mode dual-fuel (DMDF) combustion concept was optimized in a compression-ignition engine by combining the computational fluid dynamics (CFD) simulations with the genetic algorithm. Seven operating parameters with remarkable influences on the engine performance were chosen as the variables to be optimized for simultaneously m...

Oxygenated fuels are usually employed as alternative or additive fuels to gasoline and diesel fuels in order to reduce soot emissions. By involving the most recent reaction channels of PAH formation and oxidation, a reduced PAH mechanism was developed using the global sensitivity analysis for representative oxygenated fuels including methanol, n-bu...

The reliable chemical mechanisms with compact scale play an important role in engine modeling. In this research, a new method was presented to reduce the large-scale reaction kinetic mechanisms through the global sensitivity analysis on the reaction classes/sub-mechanisms in detailed mechanisms. In the present method, the importance of each reactio...

In compression ignition engines, split-injection strategy has shown great benefits in reducing pollutant emissions and improving combustion efficiency. Spray–flame interaction involving in split injections is significantly complex, which affects the ignition process and even pollutant emissions. Therefore, the objective of this study is to investig...

For accurate predictions of the combustion characteristics in constant volume combustion bombs (CVCBs), the chemical kinetics mechanism is one of the most important factors, since it determines the ignition timing and oxidation rate of fuels. By introducing an n-heptane oxidation mechanism for the simulation of auto-ignition in both CVCBs and shock...

The effectiveness of coalescence-induced jumping of micro-droplets on superhydrophobic surfaces is critical to a wide range of applications such as self-cleaning surface, anti-icing/frosting, water harvesting, phase-change heat transfer, and hotspot cooling. Introducing textures on the surfaces can readily enlarge the effective contact angle, while...

The vaporization of the fuel film after spray/wall impingement dramatically affects the combustion and emission behaviors in engines. In this study, the formation and vaporization characteristics of the fuel film were investigated by injecting diesel fuel from a single-hole injector onto a high-temperature, rough wall. The film thickness was measur...