分体式涡轮增压对船舶柴油机工作特性影响的数值模拟

为提升传统废气涡轮增压柴油机低负荷工况性能及瞬态响应特性,以某船舶推进柴油机为研究对象,建立并试验校准其一维数值仿真模型.提出了以系统综合油耗量最优为目标的分体式涡轮增压器运行策略确定方法,对比分析了采用分体式涡轮增压后柴油机各主要性能及排放参数的变化.结果表明:以柴油机各限值参数为约束,采用离散网格法可有效确定柴油机...     

电控喷油器仿真模型标定方法研究

针对电控喷油器仿真模型标定过程中,调节变量对不同工况循环喷油量的影响程度不尽相同,使得标定方案不易确定的问题,采用试验设计与分析的方法(DOE),以3个典型工况下的循环喷油量为控制目标,以6个不易测量的流量系数、摩擦因子等为控制因子,分析了控制目标量相对控制因子变动的敏感程度并排出主次关系,从而指导并完成了仿真计算模型的标定。标定结果显示:标定后的模型在各工况下的循环喷油量都达到了比较理想的精度。     

电控喷油器仿真模型标定方法研究

针对电控喷油器仿真模型标定过程中,调节变量对不同工况循环喷油量的影响程度不尽相同,使得标定方案不易确定的问题,采用试验设计与分析的方法(DOE),以3个典型工况下的循环喷油量为控制目标,以6个不易测量的流量系数、摩擦因子等为控制因子,分析了控制目标量相对控制因子变动的敏感程度并排出主次关系,从而指导并完成了仿真计算模型的标定。标定结果显示:标定后的模型在各工况下的循环喷油量都达到了比较理想的精度。     

船舶饱和蒸汽轮机动态特性仿真

介绍了船舶饱和蒸汽轮机功率、转速全工况实时仿真模型。该模型基于各守恒定律和水蒸汽物性,考虑了蒸汽的可压缩性、机内实际膨胀过程和调节级变工况特性的影响。仿真结果表明该模型稳态精度高、动态趋势合理,适用于核动力装置全工况范围正常运行和异常事故运行,此模型已在一台船舶核动力装置模拟器上得到了成功的应用。     

柴油机实时仿真物理模型的应用研究

以测得喷油规律等参数作为输入条件,用GT-Power软件建立详细发动机准维燃烧模型,运用发动机外特性性能试验数据对稳态工况进行标定,运用欧洲瞬态循环(ETC)增压压力对发动机瞬态工况下涡轮增压器瞬态特性进行标定,并对实时仿真功能发动机性能计算模型简化,保证精度的前提下提高计算速度,最后将该模型下载至硬件在环(HIL)系统进行测试。结果表明:发动机仿真物理模型能满足实时系统的要求,通过对六缸机中的一缸"断油"测试,该模型可以很好的反映喷油特性变化对发动机性能的影响。     

预喷射对船用低速柴油机性能影响的仿真研究

为了探究预喷射对船用低速柴油机性能的影响规律,利用AVL BOOST软件建立了某船用低速柴油机的仿真模型,依据其推进特性试验数据验证了模型的准确性。基于仿真模型,研究了标定工况下预喷射对柴油机有效功率、有效油耗率、最大压力增长率和NOx排放的影响。仿真结果表明:在标定工况下,预喷油量占循环供油量比例为3%与主-预喷间隔角为10℃A时,最大压力增长率和NOx排放均达到最低值,而动力性和经济性稍有下降,实现了动力性、经济性、燃烧噪声和NOx排放的折中优化。该仿真研究对进一步优化预喷方案具有一定的参考价值。     

高海拔可调两级增压柴油机油气协同控制研究

以某Ⅴ型6缸柴油机为研究对象,采用GT-Power软件开展高海拔可调两级涡轮增压柴油机油气协同控制研究。仿真模型的进气模块选用可调两级涡轮增压系统,燃烧模块的标定采用柴油机在低过量空气系数下的试验数据进行。采用该标定后的仿真模型开展了不同过量空气系数和喷油量工况下柴油机高原性能仿真计算。结果表明:在海拔4 500 m,且满足最高燃烧压力和排温限制的条件下,采用可调两级增压并结合油气协同控制,柴油机扭矩和功率可达到100%恢复;研究同时获得了最大扭矩和最大功率恢复的油气协同控制方法。     

柴电混合动力船舶机动性能研究

为解决传统机械推进系统在低速机动航行阶段出现油耗率高及环境污染严重等问题,结合柴油机驱动与电机驱动各自的优点,运用Matlab/Simulink分别建立四象限船-机-桨运动模型及柴油机、电机动力系统的动态仿真模型,对比分析低负荷机动航行工况下纯柴油机驱动船舶速度响应与电机驱动船舶速度响应及油耗量与耗电量情况。研究结果表明,低速机动航行起动工况下电动机驱动(power take in,PTI)模式具有经济、节能环保和动力性良好的优势,该研究为船舶混合动力系统的研究提供了理论支撑及指导。     

某大功率柴油机推进动力模块动态特性研究

以某型16缸大功率增压柴油机动力模块为研究对象,采用AMESim软件建立了柴油机动力模块的仿真模型,并通过试验数据对仿真模型进行了标定.基于该模型对柴油机推进动力模块加速过程中模块转速与设定值的偏差,以及瞬态调速过程中模块带大惯量运行的规律以及喷油控制优化进行了仿真研究.研究结果表明:减小涡轮增压器惯量可以优化柴油机加...     

电控单体泵燃油系统仿真研究

采用Hydsim软件建立电控单体泵系统仿真模型,并通过试验数据进行模型标定。采用该模型仿真分析了电控单体泵系统关键结构参数对其性能的影响。仿真结果表明:喷孔总流通面积与最大喷射压力成反比,与最大喷油速率成正比;高压油管长度对喷射压力和喷油速率影响很小,仅影响喷油提前角;高压油管直径对最大喷油速率影响很小,与最大喷射压力成反比。     

Design and Optimization of a Full-Generation System for Marine LNG Cold Energy Cascade Utilization

This paper took a 100,000 DWT LNG fuel powered ship as the research object. Based on the idea of "temperature matching, cascade utilization" and combined with the application conditions of the ship, a horizontal three-level nested Rankine cycle full-generation system which combined the high-temperature waste heat of the main engine flue gas with the low-temperature cold energy of LNG was proposed in this paper. Furthermore, based on the analysis and selection of the parameters which had high sen...     

Effect of parameters on performance of LNG-FPSO offloading system in offshore associated gas fields

Due to the advantages of the flexibility and economics in exploration and production of offshore liquefied natural gas (LNG), the floating production storage and offloading unit for liquefied natural gas (LNG-FPSO) has attracted wide attentions in recent years. The offloading system for LNG transportation from LNG-FPSO to LNG carrier is one of the most important parts in LNG-FPSO. The influences of the main parameters such as the mass flow rate and the height difference of the pipeline. on the performance of LNG offloading in offshore associated gas fields were investigated. A model based on a typical offshore LNG offloading system was first established and simulations were conducted. The governing equations were then used to evaluate the effects of parameters together with the simulation results. It was found that there was an economic mass flow rate for practical design on balance of the cost in pump head and BOG. The height difference of the pipeline must be considered for the increase of required pump head and harms from pressure changes. The effects of other parameters on the performance of LNG transportation such as diameter, equivalent roughness of pipeline and LNG compositions were also discussed.     

基于Aspen plus的船用双燃料发动机LNG气化流程仿真研究

采用Aspen plus软件建立了LNG气化装置的仿真模型。以ME-GI型主机的实际数据为输入,通过调用相关的热力学方法和设备模块,对气化器(VAP)中水乙二醇的进口温度、出口温度,以及LNG进口压力、LNG中甲烷浓度等参数进行模拟计算,得到上述参数对LNG气化流程出口温度、VAP换热面积及换热量的影响规律。可为VAP的节能选型提供依据;为船用双燃料发动机LNG气化流程的优化设计提供理论依据。     

内河船舶LNG发动机-蓄电池混合动力系统性能仿真

为改善船舶天然气发动机动力系统调速性能,提高内河液化天然气（LNG）燃料动力船舶的操纵性及安全性,提出构建天然气发动机-蓄电池混合动力系统。分别针对LNG发动机动力系统及混合动力系统建立Matlab/Simulink仿真模型,并实现了船舶起动和变负荷过程。对两种仿真系统的仿真结果进行分析,结果表明：采用该混合动力系统的船舶变负荷过程航速变化区间变大,系统达到稳定时间缩短;采用设计的控制策略,天然气的消耗最多降低19.6%;NOx、CO、HC排放分别最多降低22.1%、18.5%、23.6%。     

Real option valuation of free destination in long-term liquefied natural gas supplies

This paper presents a real option model for the valuation of destination flexibility in long-term LNG supplies. Stochastic price dynamics in the different markets is modelled through geometric Brownian motion processes. Mean reversion is considered as well as correlation between markets, but instead of the usual correlation in return shocks, a price convergence term is introduced representing the arbitrage streams between markets. Model parameters are estimated from market data on LNG prices by maximum log-likelihood. The goodness of the fit for the proposed model is tested as well as for two alternative models. Confidence intervals for the parameters are given. Results for the model are calculated by Monte Carlo simulation. Frequency distributions for the main results are plotted. The effect of the main parameters of the model is studied (i.e. price volatilities, price convergence, initial prices in the markets, mean reversion, extra transportation costs, number of alternative markets). The value of destination flexibility is found to be an important share of the value of LNG.     

Calculation models for prediction of Liquefied Natural Gas (LNG) ageing during ship transportation

A group of European gas transportation companies within the European Gas Research Group launched in 2007 the ‘MOLAS’ Project to provide a software program for the analysis of the Liquefied Natural Gas (LNG) ageing process during ship transportation. This program contains two different modeling approaches: a physical algorithm and an ‘intelligent’ model. Both models are fed with the same input data, which is composed of the ship characteristics (BOR and capacity), voyage duration, LNG composition, temperature, pressure, and volume occupied by liquid phase at the port of origin, together with pressure at the port of destination. The results obtained are the LNG composition, temperature and liquid volume at the port of destination. Furthermore, the physical model obtains the evolution over time of such variables en route as it is based on unsteady mass balances over the system, while the i-model applies neural networks to obtain regression coefficients from historical data composed only of origin and destination measurements. This paper describes both models and validates them from previous published models and experimental data measured in ENAGAS LNG regasification plants.     

Simulation of performance of intermediate fluid vaporizer under wide operation conditions

The intermediate fluid vaporizer (IFV) is a typical vaporizer of liquefied natural gas (LNG), which in general consists of three shell-and-tube heat exchangers (an evaporator, a condenser, and a thermolator). LNG is heated by seawater and the intermediate fluid in these heat exchangers. A one-dimensional heat transfer model for IFV is established in this paper in order to investigate the influences of structure and operation parameters on the heat transfer performance. In the rated condition, it is suggested to reduce tube diameters appropriately to get a large total heat transfer coefficient and increase the tube number to ensure the sufficient heat transfer area. According to simulation results, although the IFV capacity is much larger than the simplified-IFV (SIFV) capacity, the mode of SIFV could be recommended in some low-load cases as well. In some cases at high loads exceeding the capacity of a single IFV, it is better to add an AAV or an SCV operating to the IFV than just to increase the mass flow rate of seawater in the IFV in LNG receiving terminals.     

Ship collision impact on the structural load of an offshore wind turbine

When a maintenance and operations ship is berthing, there is a chance the ship may collide into the wind turbine. When these ships collide into wind turbine structures, this can result in significant changes to the foundation and structure of the wind turbine. In this paper, the structural load of a 4 MW offshore wind turbine was analyzed during a collision with an operations and maintenance ship. The variations in the wind speeds on hub height, waves, and the sea currents were measured. The dynamic simulation of the wind turbine was carried out using the test data as the input parameters. As a result, the load condition of the turbine without a collision was obtained. Finally, the measured turbine load was compared with the simulation results. This study shows that the collision of the operation and the maintenance ship increases the bending moments at the tower’s bottom and the blade’s roots.     

LNG运输船气体管理系统设计

对液化天然气(liquefied natural gas,LNG)运输船气体管理系统开展设计研究。分析表明:在不同船舶工况下,气体管理系统可通过透气桅放气、气体燃烧单元(gas combustion unit,GCU)燃烧、再液化、喷淋、再气化等方式将LNG运输船货舱舱压控制在安全范围内;能够在货舱蒸发气(boil off gas,BOG)量充足或者不足的情况下对主机/发电机组进行燃气供给。在船舶实际运行过程中协调采用多种气体处理模式可保障LNG运输船安全稳定运行。     

A liquefied energy chain for transport and utilization of natural gas for power production with CO2 capture and storage – Part 3: The combined carrier and onshore storage

A novel energy and cost effective transport chain for stranded natural gas utilized for power production with CO₂ capture and storage is developed. It includes an offshore section, a combined gas carrier and an integrated receiving terminal. The combined carrier will transport liquid carbon dioxide (LCO₂) and liquid nitrogen (LIN) outbound, where natural gas (NG) is cooled and liquefied to LNG by vaporization of LIN and LCO₂ onboard the carrier. The same carrier is used to transport the LNG onshore, where the NG can be used for power production with CO₂ capture. The combined carrier consists of 10 cylindrical tanks with a diameter of 9.2 m and varying lengths from 14 to 40 m. The total ship volume is 13,000 m³. Assuming 85% capture rate of the CO₂, the maximum ship utilization factor (SUF) is 63.4%. Due to the combined use of the storage tanks, the SUF is decreased with 1.4% points to 62%. The ship is equipped with a bi-directional submerged turret loading for anchoring and loading of NG and unloading of CO₂. Two ships can deliver NG to and remove CO₂ from a 400 MW_net power plant, and still obtain continuous production of LNG offshore without intermediate storage. The investment cost for each gas carrier is 40 million EUR giving total transport cost of 16.9 EUR/tonne LNG. The cost for the offshore transfer system is 6.6 million EUR per tonne LNG, whereas the cost for onshore storage and loading system is 3.1 and 0.8 million EUR per tonne LNG, respectively. The total specific costs for the ship transport, including onshore storage, loading shipping and offshore unloading are 27.5 EUR per tonne LNG for a roundtrip of 5 days, including voyage, production of LNG, unloading, connecting and berthing.