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Numerical Modelling of a Supersonic Axial Turbine Stator

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Journal of Thermal Science 2010年第3期19卷 211-217页

作者： Aki Grnman Teemu Turunen-Saaresti Ahti Jaatinen Jari Backman lut Energy Lappeenranta University of TechnologyP.O.Box 20FI-53851 LappeenrantaFinland

In order to improve the turbocharging process,a supersonic axial turbine stator was modelled numerically with a pulsatile inlet mass *** main objectives of the study were to find out how pulsation affects the flow field and the performance of the *** the beginning of the study,a supersonic turbine stator was modelled using three different techniques:quasi-steady,time-accurate with constant boundary conditions and time-accurate with a pulsatile inlet mass *** time-averaged and quasi-steady flow fields and performance were compared,and the flow field and stator performance with a pulsatile inlet mass flow was studied in detail at different time-steps.A hysteresis-like behaviour was captured when the total-to-static pressure ratio and efficiency were plotted as a function of the inlet mass flow over one pulse *** total-to-static pressure ratio and efficiency followed the sinusoidal shape of the inlet flow as a function of *** was also concluded that the stator efficiency decreases downstream from the stator trailing edge and the amplitude of the pulsating mass flow is decreased at the stator throat.

关键词： CFD Supersonic Turbine Stator Turbocharging

Evaluation of greenhouse gas emission reduction potential of a demand–response solution:a carbon handprint case study of a virtual power plant

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Clean Energy 2023年第4期7卷 755-766页

作者： J.Sillman L.Lakanen S.Annala K.Gronman M.Luoranen R.Soukka lut university School of Energy SystemsSustainability SciencePO Box 2053851 LappeenrantaFinland

The transition towards zero-carbon energy production is necessary to limit global *** energy systems have facilitated the control of demand-side resources to maintain the stability of the power grid and to provide balancing power for increasing renewable energy *** power plants are examples of demand–response solutions,which may also enable greenhouse gas(GHG)emission reductions due to the lower need for fossil-based balancing energy in the grid and the increased share of *** aim of this study is to show how potential GHG emission reductions can be assessed through the carbon handprint approach for a virtual power plant(VPP)in a grid balancing market in *** to our results,VPP can reduce the hourly based GHG emissions in the studied Finnish grid systems compared with the balancing power without the *** energy sources used for the balance power are hydropower and fossil *** reduction potential of GHG emissions varies from 68%to 98%depending on the share of the used energy source for the power balancing,thus VPPs have the potential to significantly reduce GHG emissions of electricity production and hence help mitigate climate change.

关键词： virtual power plant demand–response carbon handprint greenhouse gas emissions electric grid

Implementation of National Renewable Energy Obligations at the Regional Level

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Journal of Sustainable Bioenergy Systems 2019年第4期9卷 155-168页

作者： Mika Laihanen Antti Karhunen Tapio Ranta lut university LUT School of Energy Systems Lappeenranta Finland

The aim of the paper described here was to clarify the potential of decreasing the use of fossil fuels regionally. According to Finnish national obligations, the use of oil and other fossil fuels should be minimised by 2030. The study combines the regional consumption of primary energy sources with national obligations introduced in the national climate and energy strategy. This set up a basis when evaluating the regional state of future energy supply for 2030. The paper utilises the region of South Savo as a case study. In the region, the consumption of renewable energy sources is already above the national average, but it can be increased further by 2030. Wood fuels and especially forest biomass have regionally a major role. Local and national targets, support schemes and willingness to invest play key roles when increasing the use of renewable energy sources in the future.

关键词： Regional Biomass Forest Residues Renewable Energy

Analysis of Vibration and Noise of Induction Motor Equipped with Concentric Single-Double-Layer Star-Delta Winding

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Chinese Journal of Electrical Engineering 2019年第1期5卷 36-46页

作者： Zechen Li Chong Di Xiaohua Bao Hefei university of Technology School of Electrical Engineering and AutomationHefei 230009China Department of Electrical Engineering LUT School of Energy SystemsLappeenranta University of TechnologyLappeenranta 53851Finland

Compared with changing the structure of a motor that has been manufactured,changing the type of stator winding is an economical and time-saving method to reduce the vibration and ***,a concentric single-double-layer star-delta(CSDLSD)winding for an induction motor is described in this paper with the aim of reducing the noise of the *** planning the turns relationship between the two parts of the winding,the harmonic component of the air-gap magnetic field can be *** this,through adjusting the turns ratio in each slot of concentric winding per phase respectively,the waveform of the air-gap magnetic field becomes closer to a sinusoidal *** motors equipped with the CSDLSD winding and another two types of stator winding were *** theoretical analysis and the two-dimensional finite element method(2D-FEM)were combined to study the relationship between the harmonics of the air-gap magnetic field and the stator ***,a 2D fast Fourier transformation(2D-FFT)method was used to obtain the time-frequency spectrum of the air-gap flux density and electromagnetic excitation force,and compared with a natural vibration *** noise distribution was obtained using the harmonic *** results of the theoretical analysis,2D-FEM,2D-FFT,and harmonic response corroborate each other such that the motor applying CSDLSD winding could reduce both the vibration and noise.

关键词： Induction motor concentric single-double-layer star-delta winding 2D-FFT vibration

A Geographical-Origin-Destination Model for Calculating the Cost of Multimodal Forest-Fuel Transportation

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Journal of Geographic Information System 2013年第1期5卷 96-108页

作者： Olli-Jussi Korpinen Eero Jappinen Tapio Ranta lut Savo Sustainable Technologies Lappeenranta University of Technology(LUT)MikkeliFinland

As a consequence of increasing demand for wood fuels, the management of forest-fuel production chains has become an important logistics issue in FinlandandSweden. Truck-based transportation has been the dominant method in fuel supply from the areas around power plants. However, increasing demand has led to enlargement of supply areas and greater variety in supply methods, including also railway and waterway transportation. This study presents a GIS-based calculation model suitable for cost calculations for power plants’ forest-fuel supply chains. The model has multimodal properties—i.e., it provides transfer of forest-fuel loads between transportation modes—and enables case-specific adjustment of transportation and material-handling cost parameters. The functionality of the model is examined with a case study focusing on a region of intense forest-fuel use. The results indicate that truck transportation is competitive with railway transportation also for long transport distances. However, increasing the proportion of multimodal transportation for other than economic reasons (e.g., for supply security) could be reasonable, since the impact on total supply costs is marginal. In addition to honing of the parameters related to biomass availability and transport costs, the model should be developed through inclusion of other means of transportation, such as roundwood carriers.

关键词： Transportation Forest Fuels Railway Waterway GIS

Co-creation Based Real-Time Simulation

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Co-creation Based Real-Time Simulation

Impact of Alternative Raw Materials on the Profitability of a Large-Scale Bio-Coal Pellet Plant in Finland

第十届全国多体动力学与控制暨第五届全国航天动力学与控制学术会议

作者： Aki M.Mikkola Lappeenranta university of Technology (lut)

Traditionally,product and service development decisions have been made by expert staff far from *** decisions have been based,for the most part,on relevant technical *** the product development work,digital tools such like finite element method,multibody system dynamics are used to speed up design process and to ensure that a product will have targeted technical features as illustrated in figure 1 A).In

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Journal of Sustainable Bioenergy Systems 2019年第1期9卷 1-15页

作者： Jarno Fohr Raghu KC Kalle Karttunen Tapio Ranta Laboratory of Bioenergy Lappeenranta-Lahti University of Technology LUTMikkeliFinland

The aim of this paper was to compare the annual economic impact of a large-scale bio-coal pellet plant by raw material specifically for the Finnish Lakeland region. In this study, the total production volume of the theoretical plant was 200,000 tons per year and the raw wood materials used were birch pulpwood, spruce pulpwood, pine pulpwood, and energy wood. These wood materials were young delimbed wood from early thinnings. The main goal of the paper was to illustrate that the energy content differences of raw wood materials affect the economic profitability of a bio-coal pellet plant at regional level. In this case, wood type also has a regional economic impact, which the pellet plant can influence through its raw wood material choices. The raw material comparison was based on measured data and not computational or literary data alone. The study found that lower solid wood energy densities caused higher relative costs for the total supply chain. A parallel phenomenon occurred with the required gross margin of the pellets, where lower energy content caused higher required gross margin for pellet sales. The gross margin was also sensitivity analyzed at different discount rates from 5% to 20%. At each required discount rate, the highest annual economic impact on the region was found for birch pellets, with values of 36.95 - 42.66 million €. Spruce pellets had the smallest annual economic impact, although it had the highest final pellet price in the same cases. The different economic effects were caused by the energy volumes sold.

关键词： Bio-Coal Pellet Plant Profitability Raw Material Region

Component modeling and updating method of integrated energy systems based on knowledge distillation

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Energy and AI 2024年第2期16卷 184-199页

作者： Xueru Lin Wei Zhong Xiaojie Lin Yi Zhou Long Jiang Liuliu Du-Ikonen Long Huang Shanghai Institute for Advanced Study Zhejiang UniversityShanghaiChina College of Energy Engineering Zhejiang UniversityHangzhouChina Jiaxing Research Institute Zhejiang UniversityJiaxingChina Department of Sustainability Science LUT UniversityLappeenrantaFinland School of Intelligent Manufacturing Ecosystem Xi'an Jiaotong-Liverpool UniversitySuzhouChina

Amid the backdrop of carbon neutrality, traditional energy production is transitioning towards integrated energy systems (IES), where model-based scheduling is key in scenarios with multiple uncertainties on both supply and demand sides. The development of artificial intelligence algorithms, has resolved issues related to model accuracy. However, under conditions of high proportion renewable energy integration, component load adjustments require increased flexibility, so the mathematical model of the component must adapt to constantly changing operating conditions. Therefore, the identification of operating condition changes and rapid model updating are pressing issues. This study proposes a modeling and updating method for IES components based on knowledge distillation. The core of this modeling method is the light weighting of the model, which is achieved through a knowledge distillation method, using a teacher-student mode to compress complex neural network models. The triggering of model updates is achieved through principal component analysis. The study also analyzes the impact of model errors caused by delayed model updates on the overall scheduling of IES. Case studies are conducted on critical components in IES, including coal-fired boilers and turbines. The results show that the time consumption for model updating is reduced by 76.67 % using the proposed method. Under changing conditions, compared with two traditional models, the average deviation of this method is reduced by 12.61 % and 3.49 %, respectively, thereby improving the model's adaptability. The necessity of updating the component model is further analyzed, as a 1.00 % mean squared error in the component model may lead to a power deviation of 0.075 MW. This method provides real-time, adaptable support for IES data modeling and updates.

关键词： Component modeling Adaptive update Knowledge distillation Variable operating conditions Integrated energy system Data-driven

The Role of Bioenergy in Achieving the Carbon Neutrality Target in Finland by 2035—A Case Study of Student Surveyed at university in Finland

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Journal of Sustainable Bioenergy Systems 2021年第2期11卷 61-81页

作者： Tapio Ranta Mika Laihanen Antti Karhunen Lappeenranta-Lahti university of Technology LUT School of Energy Systems Lappeenranta Finland

The largest share of renewable energy in Finland comes from bioenergy. In 2019, bioenergy accounted for 82% (416 PJ, 116 TWh) of renewable energy in Finland. This study assesses the potential for increasing bioenergy in energy production by 2035 and what role it will play in achieving the carbon neutrality target in Finland. The role of different energy sources in the energy system was examined using existing scenarios developed for The National Long-Term Strategy. Two alternative low-emission scenarios have been developed to last until 2050 to meet the 2035 carbon neutrality target. In 2035, the amount of bioenergy has risen to 520 - 550 PJ (144 - 153 TWh), which is about 70% of renewable energy consumption. This means, that the bioenergy resource has been fully deployed and the relative share of bioenergy in renewables has decreased slightly. The study also included a survey to university students to map out how likely a carbon neutrality target is to be considered by 2035. university students were unsure of achieving the carbon neutrality target by 2035. The schedule was considered challenging especially in the transport sector. Bioenergy was also seen as still playing an important role, especially in heat production. Achieving significant emission reductions will require significant electrification

关键词： Bioenergy Renewable Energies CO2 Reduction Strategies Policies Education