Power Engineering Research Articles

Research on the Ignition Strategy of Diesel Direct Injection Combined with Jet Flame on the Combustion Character of Natural Gas in a Dual-Fuel Marine Engine

In large-bore two-stroke diesel/nature gas dual-fuel marine engines, a certain quantity of diesel is injected into the cylinder to satisfy the full-power output engine rated power of the gas mixture. However, the ignition and flame propagation process based on the injection strategy of diesel direct injection combined with diesel jet flame on the ignition and combustion of natural gas is unclear, which directly affects the power and the thermal efficiency of engine and emissions. Therefore, this work numerically investigates the flame propagation characteristic under the strategy of the main and pilot diesel modes. The influence of the injection timing and proportion of diesel on combustion and emission performance are further analyzed. The results show that the influence of the injection timing of main diesel (MDIT) on the combustion process and emission performance is more obvious than that of the injection timing of pilot diesel (PDIT). The results indicate that the MDIT increased from −2°CA to −8°CA, the power increased by 316 kW, and the thermal efficiency improved by 1.5%. However, the CO2 emissions increased by 10.5 g/kWh, and the NOx emissions increased by 0.7 g/kWh. Additionally, an early PDIT is not conducive to the rapid organization of combustion, resulting in decreased engine power and thermal efficiency. Furthermore, it was found that the power improved by 50 kW and the thermal efficiency improved by 0.6%, with a decrease in the main diesel ratio (MDR) from 100% to 90%. Meanwhile, the CO2 emissions decreased by 4 g/kWh, although there was no obvious change in NOx emissions with the advance of MDR.

A Kriging Surrogate Model for Ball Grid Array Electronic Packaging With Stochastic Material and Geometrical Parameters

Abstract Ball grid arrays (BGAs) offer significant advantages in the automotive industry, such as their small size and high integration density, making them a promising electronic packaging approach. However, the operating environment of automobiles is more complex compared to other applications, primarily due to vibrations generated by power engines and oscillations caused by pavement roughness. The resonant frequencies of electronic packaging structures play a crucial role in system reliability and safety. However, accurately describing the implicit relationship between system resonant frequencies and material and geometrical parameters can be challenging. A Kriging surrogate model (KSM) is proposed by the combination of the Latin Hypercube stochastic sampling with finite element computation. Four different BGA configurations are established with either the initial values in the deterministic model or the specified sampling interval ranges in the stochastic model. The results of the finite element model (FEM) for BGA electronic packaging are validated and demonstrate qualitative agreement with published literature. The impacts of material and geometrical parameters on the resonant frequencies are investigated and compared. The mean, maximum, minimum, and variance are recorded based on a large database of stochastic samples. The feasibility of KSM for the resonant frequency prediction of BGA is confirmed by its satisfactory accuracy and computational efficiency.

A MODEL FOR CONSTRUCTION SECTOR DEVELOPMENT IN MIDDLE-INCOME SUB-SAHARAN AFRICAN COUNTRIES

Buildings and other constructed facilities form the essential framework of a country’s physical and economic infrastructure. Construction serves as a key capital input to production, driving economic growth and wealth generation. This impact can be particularly transformative in low-to-middle-income countries. Physical infrastructure, including construction, is a powerful engine of economic growth and is closely related to national economic performance. However, not all studies agree with the commonly held belief that construction investment has a positive impact on economic growth, particularly concerning the amount of investment and the relationship between construction investment and economic growth. So far, cross-country studies dealing with the construction sector-economic growth relationship have used indicators of national output and construction that are not strictly comparable between countries. This article reviews the main strands of the literature on the role that the construction sector plays in the national economy and economic development. It also uses novel data drawn from the “capital file” of the PENN World Table (version 10.1) to assess the development pattern of the construction sector in two groups of sub-Saharan African (SSA) countries on the middle-income status of economic development, for the period between 1990 and 2019. The study reveals that construction shares, measured as the proportion of gross fixed capital formation attributable to construction in the gross domestic product, revolve around a norm determined by the level of built assets preceding the reference period. The results of the study could have policy implications for the economic sustainability of the construction industry in SSA.

Wind-Induced Response Analysis and Fatigue Life Prediction of a Hybrid Wind Turbine Tower Combining an Upper Steel Tube with a Lower Steel Truss

Based on the WindPACT-3MW wind turbine tower commonly used in wind power engineering, a finite element model (FEM) of a hybrid wind turbine tower combining an upper steel tube with a lower steel truss is designed and established. On this basis, a static optimization analysis, wind-induced vibration analysis, and fatigue life analysis of the hybrid tower structure are performed. The results show that under the same design parameters, the overall stiffness and static bearing capacity of the tower structure can be significantly improved by using subdivided truss webs, increasing the truss height as much as possible and increasing the width of the truss base appropriately. Under normal operation conditions, the response of the tower structure in the along-wind direction is significantly greater than the response in the crosswind direction, indicating that the aerodynamic thrust generated by the rotation of the blades is the main factor causing the wind-induced vibration of the tower structure. For the tower structure analyzed in this study, when considering the entire range of wind speeds from the cut-in wind speed to the cut-out wind speed, the fatigue life of the structure is 38.5 years.

Study on Consumption Preference of New Energy Vehicles

The sales volume and sales volume of new energy vehicles in the market reflect the public's use of new energy vehicles. According to the feedback and demand of different people, the purchase proportion of new energy vehicles and new energy vehicles is different. The impact on economic development and the impact on the purchasing economy. The psychological impact of people using new energy vehicles. Consumers' pursuit of new energy vehicle performance (breakthroughs in speed and road use quality. Changes in conventional engine power output and motor output. The psychological impact on the use of new energy vehicles. Consumers' pursuit of new energy vehicle performance. After-sales quality assurance and service, the impact of different age groups on new energy vehicles. And the impact on the economic development of the population and the purchasing population, different age groups have different demands for new energy vehicles. After-sales service has also improved with market changes, and more and more people are pursuing the purchase of new energy vehicles. China's new energy vehicle policy will have an impact on the price of cars and buyers.

Maximum power of coupled-qubit Otto engines

We put forward four schemes of a coupled-qubit quantum Otto machine, a generalization of the single-qubit quantum Otto machine, based on work and heat transfer between an internal system consisting of a coupled pair of qubits and an external environment consisting of two heat baths and two work storages. The four schemes of our model are defined by the positions of attaching the heat baths, which play a key role in the power of the coupled-qubit engine. First, for the single-qubit heat engine, we find a maximum-power relation, and the fact that its efficiency at the maximum power is equal to the Otto efficiency, which is greater than the Curzon-Ahlborn efficiency. Second, we compare the coupled-qubit engines to the single-qubit engine from the point of view of achieving the maximum power based on the same energy-level change for work production and find that the coupling between the two qubits can lead to greater powers but the system efficiency at the maximum power is lower than the single-qubit system's efficiency and the Curzon-Ahlborn efficiency. Published by the American Physical Society 2024

Landauer Bound in the Context of Minimal Physical Principles: Meaning, Experimental Verification, Controversies and Perspectives

The physical roots, interpretation, controversies, and precise meaning of the Landauer principle are surveyed. The Landauer principle is a physical principle defining the lower theoretical limit of energy consumption necessary for computation. It states that an irreversible change in information stored in a computer, such as merging two computational paths, dissipates a minimum amount of heat kBTln2 per a bit of information to its surroundings. The Landauer principle is discussed in the context of fundamental physical limiting principles, such as the Abbe diffraction limit, the Margolus–Levitin limit, and the Bekenstein limit. Synthesis of the Landauer bound with the Abbe, Margolus–Levitin, and Bekenstein limits yields the minimal time of computation, which scales as τmin~hkBT. Decreasing the temperature of a thermal bath will decrease the energy consumption of a single computation, but in parallel, it will slow the computation. The Landauer principle bridges John Archibald Wheeler’s “it from bit” paradigm and thermodynamics. Experimental verifications of the Landauer principle are surveyed. The interrelation between thermodynamic and logical irreversibility is addressed. Generalization of the Landauer principle to quantum and non-equilibrium systems is addressed. The Landauer principle represents the powerful heuristic principle bridging physics, information theory, and computer engineering.

What Role Does Simulation Play in Sustainable Industrial Development?

Sustainability as a concept is present in most aspects of our everyday life, and industry is no exception. Likewise, there is no doubt that the necessity to produce goods in a sustainable way and to ensure that products are sustainable is gaining more and more attention from producers, customers, governments, and various organizations. Understandably, there are several ways to increase the sustainable development of industrial production. One effective tool is simulation, which can have a significant impact on improving environmental, economic, and social sustainability. This paper explores the role of simulation as a powerful scientific and engineering solution in advancing sustainability within industrial ecosystems. Its main scope is to map the existing literature on the usage of simulation as a supportive tool for achieving this goal. For this purpose, a bibliometric analysis was conducted, allowing for tailored insights into the use of simulation in sustainable production.

A numerical investigation on enhancing the performance of a diesel engine fuelled with diesel‐biodiesel blend using a diethyl ether as an additive

AbstractGlobally, the encouragement of using renewable fuels like biodiesel for diesel engines is driven by concerns over the fossil fuel depletion and harmful emissions. Additionally, the utilization of renewable fuel additives like diethyl ether has the potential to enhance fuel properties and boost engine performance. The aim of this paper was to construct a computer simulation using Ricardo Wave program in order to predict the performance and nitrogen oxides (NOx) emission of a diesel engine fuelled by a diesel‐biodiesel blend and a diethyl ether (DEE) as a fuel additive. The computer model was validated by comparing the simulation engine performance and NOx emission results against the corresponding experimental data for diesel, diesel‐biodiesel blend with 30% biodiesel proportion (B30), and two blends of diesel‐biodiesel‐DEE with DEE proportions of 5% and 10% on a volume basis. Also, the effect of varying the inlet air pressure on engine performance and NOx emission was compared for all investigated fuels. It was numerically demonstrated that using the DEE with an optimum proportion of 5% enhanced engine performance as it decreased engine fuel consumption by 5.9% and increased engine thermal efficiency by 9.6% compared to diesel fuel at engine full load condition. Also, a significant reduction of 20.5% in NOx emission resulted from the addition of DEE. Increasing the inlet air pressure increased engine power and decreased engine fuel consumption for all investigated fuels. Increasing the inlet air pressure from 1 to 3 bar increased engine brake thermal efficiency by almost 20% for all tested fuels. However, NOx emission increased slightly within a range from 1.7% to 7% for the different investigated fuels.

Обоснование оптимальных наработок основных насосов карьерного гидравлического экскаватора

As the pump operates and wears out, the gap in the friction pairs increases and the volumetric efficiency decreases, the pump flow gets reduced, which leads to increasing duration of working and auxiliary operations, the operating cycle of the excavator, a decrease in its productivity and excessive fuel consumption. Infrequent pump replacement can lead to a significant increase in fuel consumption and reduced excavator performance. If the pump is replaced prematurely, its service life will not be used to the full extent. In order to develop a method for establishing optimal operating hours that allow minimizing fuel consumption and the cost of replacing a pump, taking into account operating conditions, a mathematical model of the pump operation is proposed, which makes it possible to obtain an expression for determining the differentiated optimal value of operating time between replacements. A calculation method and a software algorithm have been developed in the MatLab Simulink software suite to calculate the rate of decrease in the volumetric efficiency, as well as to establish the influence of volumetric efficiency on the fuel consumption and performance of a hydraulic excavator to be utilized in the model using the example of the HPV375 pump of the Komatsu PC2000-8 excavator, Based on the proposed mathematical model of the main pumps operation, a method has been developed for calculating the differentiated operating time between replacements of the main pumps of a mining hydraulic excavator, taking into account the rate of decrease in volumetric efficiency, replacement costs and damage due to changes in productivity and excessive fuel consumption. The dependence of the rate of changes in the volumetric efficiency of the pump is presented for the excavation, viscosity, contamination and temperature of the working fluid parameters. A coefficient of “reserve of partial engine power transferred to the pump” is proposed, determined by the ratio of the difference between the average maximum and initial partial power to the value of the initial partial power, which allows estimation of the operating time of the main pumps without affecting productivity of the excavator.

Detailed modelling and performance analysis of power flow topology in a hybrid electric vehicle having series-parallel architecture

Despite massive investment and carbon-neutral transition goals set around the world, gasoline-based internal combustion engine vehicles still form an absolute majority in the transportation sector. With the advent of technology, access to electricity, uncertainties in fuel prices and health awareness, people worldwide are moving towards a better, reliable, cost-effective and environmentally friendly mode of transportation, a hybrid electric vehicle. Such a vehicle, with its powerful electric motor and compact gasoline-based engine, offers better efficiency in terms of operating cost and reliability. Considering the advent of hybrid electric vehicles taking pace, studies related to its architecture types, power flow dynamics, control and modelling of its various components will form an essential part of the automobile industry and research. This paper proposes a power flow topology for a hybrid electric vehicle with series-parallel architecture. The developed vehicle model with such an architecture type consists of three main sub-systems: the electrical system, the control system and the mechanical system. The presented power flow topology being modelled and analysed in detail in the Simulink tool is being implemented via a mode logic controller, which forms part of the central control system. The developed hybrid electric vehicle model demonstrates various modes of operation, from starting to accelerating to de-accelerating and then finally coming to a complete rest. Each mode yields and explains the following: the vehicle reference speed; the engine and generator turn functions on/off; the dc bus and battery voltage; the motor, battery, and generator current; the motor, generator, and engine speed; engine torque; engine power; throttle demand; and the vehicle’s actual speed. The results thus obtained show that the waveforms associated with such topology, during its various modes of operation, are pretty stable and acceptable, thereby depicting and validating the operation of the developed hybrid electric vehicle model with proposed power flow topology in a precise and transparent manner.

Optimization and comparative evaluation of novel marine engines integrated with fuel cells using sustainable fuel choices

Large ships are more utilized than ever before to facilitate transporting heavy goods and oils overseas. However, they rely on fossil fuels and cause severe environmental impacts. Utilizing alternative fuels and implementing new engine designs are considered promising methods to reduce greenhouse gas emissions and improve engine performance. This paper compares three developed, hybridized marine engines operated using five fuel blends of hydrogen, methanol, dimethyl ether, ethanol, and methane. In addition, the paper presents a multi-objective particle swarm optimization to increase the engine power and its exergetic efficiency and reduce the cost and environmental impact. A marine engine (SRC-GT-SOFC) containing a steam Rankine cycle, a gas turbine, and a solid oxide fuel cell is considered to weigh less and perform better. It is found that the optimized SRC-GT-SOFC engine power is increased by about 10 %, corresponding to 16269 kW with an increased exergetic efficiency of 70.6 %, respectively. Its specific fuel and product exergetic costs are found to be 12 $/GJ and 15.67 $/GJ, and its specific fuel and product environmental impacts are 7.4 Pt/GJ and 9.3 Pt/GJ, respectively. This results in a significant reduction in the relative cost difference and the relative environmental impact difference of the optimized SRC-GT-SOFC of 30 % and 25.4 %, respectively.

A comparative investigation of the operating performance and emission characteristics of various diesel engines driving the firefighting pump

The investigation of engines with different performances driving the same load-consuming device is necessary for practical applications. In this paper, three diesel engines with varying capacities for driving the same firefighting pump for high-rise residential buildings were studied and compared for their performance, combustion parameters, and emissions by the simulation method. The AVL BOOST software is utilized to establish theoretical combustion models for these engines. The operating balance point of each engine is determined, and the appropriate transmission ratio of the drive train system is proposed to be applied. The results show that the working partial load modes of Model 1 at 91 % engine load and 2970 rpm, Model 2 at 74 % engine load and 2960 rpm, and Model 3 at 57 % engine load and 2490 rpm. The engine works in its higher load mode, producing higher brake specific fuel consumption (BSFC), higher NOx and CO emissions, lower soot formation, and vice versa. The engine operates at its lower load, resulting in decreased BSFC, less NOx and CO emissions, and more soot generation. The results suggest that Model 2 in the present work is the option that can balance the factors of engine power, initial investment cost, fuel consumption economics, and emissions. The findings obtained from this work are the scientific foundations to support the design of the firefighting pump systems when considering comprehensive factors of technical technology, investment cost, and environmental consideration.

Impact of pilot diesel injection timing on performance and emission characteristics of marine natural gas/diesel dual-fuel engine

In diesel-ignited natural gas marine dual-fuel engines, the pilot diesel injection timing (PDIT) determines the premixing time and ignition moment of the combustible mixture in the cylinder. The PDIT plays a crucial role in the subsequent development of natural gas flame combustion. In this paper, four PDITs (− 8 °CA, − 6 °CA, − 4 °CA, and − 2 °CA) were studied. The results show that the advancement of PDIT increased the engine's power, thermal efficiency, and natural gas flame spread velocity, and increased NO emissions and CH4 emissions of the marine engine. The PDIT affected the ignition delay period and the rapid combustion period to a greater extent than the slow combustion period and the post combustion period. With each 2 °CA advancement of PDIT, the engine's power increased by 69.87 kW, thermal efficiency increased by 0.42%, radial flame spread velocity increased by 2 m/s, axial flame spread velocity increased by 1.7 m/s, NO emissions increased by 6.1%, and CH4 emissions increased by 3.75%.

Research on the Development of Thermal Power Engineering Based on Energy and Boilers

Research on the Development of Thermal Power Engineering Based on Energy and Boilers

Digital carbon neutrality: evidence of carbon emission reduction based on digital inclusive finance.

As a powerful engine for economic reform and curbing carbon emissions, digital inclusive finance provides solid support for achieving the goal of digital carbon neutrality. This study reveals the positive effect of digital inclusive finance on carbon emission reduction and the deeper reasons behind it by digging deeper into the panel data of 213 cities in China. The study adopts advanced empirical analysis methods to rigorously test the association between digital inclusive finance and carbon emissions. The results show that there is a strong positive correlation between the booming development of digital inclusive finance and the significant decline in carbon emissions. This finding remains solid after several rounds of robustness tests, which fully proves the reliability of the research results. Further mechanism analysis reveals the multiple paths of digital financial inclusion on carbon emission reduction. First, it promotes the optimization and upgrading of industrial structure by optimizing the allocation of financial resources, thus reducing the proportion of high-carbon emission industries. Second, digital inclusive finance attracts more foreign capital inflows and introduces advanced low-carbon technologies and management experience, further promoting the development of low-carbon economy. In addition, the study also found that the differences between different cities in terms of geographic location and city size have a significant impact on the carbon emission reduction effect of digital inclusive finance. In particular, the carbon emission reduction effect of digital inclusive finance is particularly significant in western regions, central cities, and first-tier cities. In response to these findings, this paper proposes a series of targeted policy recommendations. First, the financial service system should be further optimized to increase the coverage and penetration of digital inclusive finance, especially in less developed regions and small- and medium-sized cities. Second, regional policy synergies should be strengthened to form a strong synergy to promote the development of a low-carbon economy. In addition, it should guide capital flows to low-carbon industries and encourage enterprises to increase green technology research and development and application, while actively promoting low-carbon consumption concepts and guiding consumers to form green consumption habits. Through the implementation of these measures, it is expected that the potential of digital inclusive finance in the development of a low-carbon economy will be further stimulated, making a greater contribution to the realization of the goals of carbon peaking and carbon neutrality.

EVALUATION OF THE ENERGY EFFICIENCY OF THE NEW CONSTRUCTIVE SOLUTION OF SUCKER-ROD PUMP

As is known, in our country, oil production is carried out both in the Caspian Sea and in oil fields on land. For the mechanized exploitation of oil fields on land, in most cases used different type of sucker-rod pumps. The main object of the study of the article is a new constructive solution of the pumping unit, the novelty of which is approved by the ownership certificates of the Eurasian Patent Organization and the Intellectual Property Organization of the Republic of Azerbaijan. The main factor characterizing the operation of pumping units is its quality indicators such as metal consumption, reliability, efficiency and energy consumption. When switching from a balanced sucker-rod pumping unit to an unbalanced the efficiency factor decreases from 0.834 to 0.65 and decreases from 0.605 to 0.312. In this case, power losses increase sharply not only in transmissions, but also in energy distribution networks. If the engine is not fully loaded or is not selected correctly, then these energy coefficients decrease even more. The selection of engine power is performed according to the worst conditions, i.e. the cyclic mode of operation of an unbalanced pumping unit. Despite this, it can be said that in almost all oil fields, the power of asynchronous motors is greatly exaggerated, which causes additional losses. In article proposed expressions for determining the optimal power of the electric motor were proposed, taking into account the efficiency factor of the balancing device during the balancing of the proposed new constructive solution of the beamless pumping unit with a combined, movable counter weights and rotary counter weights. This allows to prevent excess energy consumption and reduce energy costs. Which is very important in the era of globalization, when energy prices are rising sharply.

A numerical method for two-dimensional transient nonlinear convection-diffusion equations

In this research, we have developed the half-boundary method (HBM) for nonlinear convection-diffusion equations (CDEs), which hold significant importance in nuclear power engineering. The HBM employs a variable relationship between the nodes within the computational domain and the nodes located on half of the boundaries. This approach offers notable benefits, includingthe reduction ofthe maximum matrix order and the optimization the maximum memory storage for calculations. Moreover, the HBM is an efficient and streamlined approach to directly handle Neumann boundary conditions, thanks to the utilization of mixed variables. We primarily investigate the memory usage and accuracy of the proposed algorithm in the unsteady-state CDEs, in context of material nonlinear CDEs, the Burgers’ equation and the system of Burgers' equations. The numerical results obtained demonstrate the method’s potential in simulating flow and heat transfer phenomena, particularly in situations where convection is dominant.

Civil site selection of the gas engine power plant by value-based decision multicriteria in Kupang, Indonesia

Civil site selection of the gas engine power plant by value-based decision multicriteria in Kupang, Indonesia

Integrated Passive Anti-Islanding Protection in Micro Grid

In last two decades due to major interest amongst power system engineers and policy makers penetration of different distributed energy resources (DREs) into power distribution network are significantly increased. Integration of DREs with conventional power grid is a complex issue and will impose some challenges against power engineers. The major challenge is protection of micro grid, which is based on how your protection strategies distinguish islanding and non islanding conditions correctly and timely. Methods used for have strengths and limitations in the areas like speed, accuracy, power quality and Non detection islanding zone. The prime motive of this research is to presents an efficient new integrated anti-islanding protection strategy using passive parameters. The proposed algorithm having a novel islanding detection technique, which discriminate the islanding events from the non islanding events of similar signature accurately with minimum non detection zone and minimum impact on power quality. The proposed strategy is the combination of different conventional and latest passive relays based on single and multiple parameters. Integration of different relays made in such a strategic way that it combines the strengths and benefits of each method and minimizes their limitations. The presented algorithm tested under MATLAB/SIMULINK environment in different network conditions. Finally, the efficiency of the algorithm has checked by testing it on standard microgrid structure. The results received from simulation confirmed that algorithm is detecting islanding conditions reliably and efficiently, followed by generation of trip/block signal correctly.