A comprehensive review of measurements and data analysis of laminar burning velocities for various fuel+air mixtures

A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.

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Wide range modeling study of dimethyl ether oxidation

Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century. A portfolio of technologies now exists to meet the world's energy needs over the next 50 years and limit atmospheric CO2 to a trajectory that avoids a doubling of the preindustrial concentration. Every element in this portfolio has passed beyond the laboratory bench and demonstration project; many are already implemented somewhere at full industrial scale. Although no element is a credible candidate for doing the entire job (or even half the job) by itself, the portfolio as a whole is large enough that not every element has to be used.

“Stabilization wedges: Solving the climate problem for the next 50 years with current technologies” from science magazine (2004)

Combustion of fuels to generate energy is integral to various human activities, both domestic and industrial. However, the predominance of hydrocarbon fuel usage produces emissions containing pollutants that cause multiple environmental complications and risks to human health. Therefore, replacement of conventional fuels to achieve zero carbon emission is of utmost importance. In terms of carbon-free fuel, ammonia offers several advantages over hydrogen. However, its low burning velocity and high fuel NOx emissions inhibit large-scale usage. Hence, hydrogen and methane have been studied in this review as possible secondary fuels to aid ammonia combustion and address the aforementioned issues. This review starts from the suitability of ammonia fuel as energy vector in terms of physicochemical and combustion characteristics, moving through the kinetics and mechanisms of ammonia-based and ammonia-fuel combustion. The impacts and limitations of each system are also addressed, thus providing a comparison on each system. Particularly, this review assesses and discusses the advantages and mechanisms involved with secondary fuel addition to the ammonia combustion, presenting the role of key reaction differences and the change in key reaction mechanism under different conditions at the level of reaction mechanisms. Finally, this review covers future perspectives and challenges on the usage and development of ammonia-based fuels, emphasizing the maturity of ammonia-based and ammonia-fuel combustion kinetics. Herein, this work summarizes the principles of the combustion reactions of ammonia-based and ammonia-fuel systematically and serves as a theoretical reference of ammonia-fuel combustion kinetics for transitioning into future practical applications where ammonia is an important energy vector.

A review on ammonia, ammonia-hydrogen and ammonia-methane fuels

Experimental and kinetic modeling investigation on the laminar flame propagation of ammonia under oxygen enrichment and elevated pressure conditions

An experimental and numerical study on laminar flame characteristics of methane oxy-fuel mixtures highly diluted with CO2 was conducted using a constant volume chamber and CHEMKIN package. The effects of high CO2 dilution on combustion chemical reaction, flame instability, and flame radiation of CH4/CO2/O2 mixtures were studied. The laminar burning velocities of CH4/CO2/O2 mixtures decrease with the increase of the CO2 fraction. CO2 directly participates in the chemical reaction through the elementary reaction OH + CO = H + CO2 and inhibits the combustion process by the competition of the H radical between the reverse reaction of OH + CO = H + CO2 and the reaction H + O2 = O + OH. This effect is more obvious for highly diluted CO2 in the case of CH4/CO2/O2 mixtures. CO2 suppresses the flame instability by the combined effect of hydrodynamic and thermal-diffusive instabilities. The radiation of CH4 oxy-fuel combustion is much stronger than that of CH4/air combustion mainly because of the existence of a lar...

Experimental and Numerical Study on Laminar Flame Characteristics of Methane Oxy-fuel Mixtures Highly Diluted with CO2

This paper is focused on the static output feedback (SOF) control problem for a class of switched nonlinear systems with actuator faults. By means of the Takagi–Sugeno fuzzy model, the switched nonlinear plant is described by a family of switched fuzzy systems. Considering transmission failures may occur between controller and actuator, a reliable SOF controller against actuator faults is designed. Sufficient conditions are developed to guarantee the existence of the reliable SOF controller. Furthermore, an iterative algorithm is designed to determine the controller gains, which avoids the conservatism brought by the traditional singular value decomposition method. To validate the effectiveness of the proposed approach, a numerical example is exploited and simulation results are also presented.

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Static Output Feedback Control of Switched Nonlinear Systems With Actuator Faults

Global buildings account for about 30% of the total energy consumption and carbon emission, raising severe energy and environmental concerns. Therefore, it is significant and urgent to develop novel smart building energy management (SBEM) technologies for the advance of energy efficient and green buildings. However, it is a nontrivial task due to the following challenges. First, it is generally difficult to develop an explicit building thermal dynamics model that is both accurate and efficient enough for building control. Second, there are many uncertain system parameters (e.g., renewable generation output, outdoor temperature, and the number of occupants). Third, there are many spatially and temporally coupled operational constraints. Fourth, building energy optimization problems can not be solved in real time by traditional methods when they have extremely large solution spaces. Fifthly, traditional building energy management methods have respective applicable premises, which means that they have low versatility when confronted with varying building environments. With the rapid development of Internet of Things technology and computation capability, artificial intelligence technology find its significant competence in control and optimization. As a general artificial intelligence technology, deep reinforcement learning (DRL) is promising to address the above challenges. Notably, the recent years have seen the surge of DRL for SBEM. However, there lacks a systematic overview of different DRL methods for SBEM. To fill the gap, this article provides a comprehensive review of DRL for SBEM from the perspective of system scale. In particular, we identify the existing unresolved issues and point out possible future research directions.

A Review of Deep Reinforcement Learning for Smart Building Energy Management

This paper investigates the dissipative filtering problem for a class of discrete-time switched fuzzy systems with missing measurements. The fuzzy plant under consideration incorporates characteristics of Takagi–Sugeno fuzzy systems and switched systems simultaneously. The occurrence of missing measurements is described by a stochastic variable that satisfies the Bernoulli binary distribution, which characterizes the effect of data loss in information transmission between the plant and the filter. Utilizing the Lyapunov function technique, sufficient conditions are developed to ensure that the resultant filtering error system is exponentially stable and strictly dissipative. Two simulation examples are presented to illustrate the validity of the proposed method.

Meng Zhang

Papers

Experimental and Numerical Study on Laminar Flame Characteristics of Methane Oxy-fuel Mixtures Highly Diluted with CO2

Static Output Feedback Control of Switched Nonlinear Systems With Actuator Faults

A Review of Deep Reinforcement Learning for Smart Building Energy Management

Dissipative Filtering for Switched Fuzzy Systems With Missing Measurements

Effects of oxygen enrichment on laminar burning velocities and Markstein lengths of CH4/O2/N2 flames at elevated pressures