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Development of a simplified n-heptane/methane model for high-pressure direct-injection natural

Jingrui LI, Haifeng LIU, Xinlei LIU, Ying YE, Hu WANG, Xinyan WANG, Hua ZHAO, Mingfa YAO

《能源前沿（英文）》 2021年 第15卷 第2期   页码 405-420 doi: 10.1007/s11708-021-0718-3

摘要： High-pressure direct-injection (HPDI) of natu-ral gas is one of the most promising solutions for future ship engines, in which the combustion process is mainly controlled by the chemical kinetics. However, the employment of detailed chemical models for the multi-dimensional combustion simulation is significantly expensive due to the large scale of the marine engine. In the present paper, a reduced -heptane/methane model consisting of 35-step reactions was constructed using multiple reduction approaches. Then this model was further reduced to include only 27 reactions by utilizing the HyChem (Hybrid Chemistry) method. An overall good agreement with the experimentally measured ignition delay data of both -heptane and methane for these two reduced models was achieved and reasonable predictions for the measured laminar flame speeds were obtained for the 35-step model. But the 27-step model cannot predict the laminar flame speed very well. In addition, these two reduced models were both able to reproduce the experimentally measured in-cylinder pressure and heat release rate profiles for a HPDI natural gas marine engine, the highest error of predicted combustion phase being 6.5%. However, the engine-out CO emission was over-predicted and the highest error of predicted NO emission was less than 12.9%. The predicted distributions of temperature and equivalence ratio by the 35-step and 27-step models are similar to those of the 334-step model. However, the predicted distributions of OH and CH O are significantly different from those of the 334-step model. In short, the reduced chemical kinetic models developed provide a high-efficient and dependable method to simulate the characteristics of combustion and emissions in HPDI natural gas marine engines.

关键词： high-pressure direct-injection     natural gas     chemical kinetics     combustion modelling     marine engine    

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Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

Yi REN,Xianguo LI

《能源前沿（英文）》 2016年 第10卷 第2期   页码 164-175 doi: 10.1007/s11708-016-0407-9

摘要： Liquid breakup in fuel spray and atomization significantly affects the consequent mixture formation, combustion behavior, and emission formation processes in a direct injection diesel engine. In this paper, different models for liquid breakup processes in high-pressure dense diesel sprays and its impact on multi-dimensional diesel engine simulation have been evaluated against experimental observations, along with the influence of the liquid breakup models and the sensitivity of model parameters on diesel sprays and diesel engine simulations. It is found that the modified Kelvin-Helmholtz (KH)–Rayleigh-Taylor (RT) breakup model gives the most reasonable predicted results in both engine simulation and high-pressure diesel spray simulation. For the standard KH-RT model, the model constant for the breakup length has a significant effect on the predictability of the model, and a fixed value of the constant cannot provide a satisfactory result for different operation conditions. The Taylor-analogy-breakup (TAB) based models and the RT model do not provide reasonable predictions for the characteristics of high-pressure sprays and simulated engine performance and emissions.

关键词： breakup model     diesel engine     high-pressure injection     simulations    

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Combustion characteristics of a direct-injection diesel engine fueled with Fischer-Tropsch diesel

HUANG Yongcheng, ZHOU Longbao, PAN Keyu

《能源前沿（英文）》 2007年 第1卷 第2期   页码 239-244 doi: 10.1007/s11708-007-0033-7

摘要： Fischer-Tropsch (F-T) diesel fuel is characterized by a high cetane number, a near-zero sulphur content and a very low aromatic level. On the basis of the recorded incylinder pressures and injector needle lifts, the combustion characteristics of an unmodified single-cylinder direct-injection diesel engine operating on F-T diesel fuel are analyzed and compared with those of conventional diesel fuel operation. The results show that F-T diesel fuel exhibits a slightly longer injection delay and injection duration, an average of 18.7% shorter ignition delay, and a comparable total combustion duration when compared to those of conventional diesel fuel. Meanwhile, F-T diesel fuel displays an average of 26.8% lower peak value of premixed burning rate and a higher peak value of diffusive burning rate. In addition, the F-T diesel engine has a slightly lower peak combustion pressure, a far lower rate of pressure rise, and a lower mechanical load and combustion noise than the conventional diesel engine. The brake specific fuel consumption is lower and the effective thermal efficiency is higher for F-T diesel fuel operation.
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of ignition timing and hydrogen fraction on combustion and emission characteristics of natural gas direct-injection

WANG Jinhua, HUANG Zuohua, LIU Bing, ZENG Ke, YU Jinrong, JIANG Deming

《能源前沿（英文）》 2008年 第2卷 第2期   页码 194-201 doi: 10.1007/s11708-008-0035-0

摘要： An experimental study on the combustion and emission characteristics of a direct-injection spark-ignited engine fueled with natural gas/hydrogen blends under various ignition timings was conducted. The results show that ignition timing has a significant influence on engine performance, combustion and emissions. The interval between the end of fuel injection and ignition timing is a very important parameter for direct-injection natural gas engines. The turbulent flow in the combustion chamber generated by the fuel jet remains high and relative strong mixture stratification is introduced when decreasing the angle interval between the end of fuel injection and ignition timing giving fast burning rates and high thermal efficiencies. The maximum cylinder gas pressure, maximum mean gas temperature, maximum rate of pressure rise and maximum heat release rate increase with the advancing of ignition timing. However, these parameters do not vary much with hydrogen addition under specific ignition timing indicating that a small hydrogen fraction addition of less than 20% in the present experiment has little influence on combustion parameters under specific ignition timing. The exhaust HC emission decreases while the exhaust CO concentration increases with the advancing of ignition timing. In the lean combustion condition, the exhaust CO does not vary much with ignition timing. At the same ignition timing, the exhaust HC decreases with hydrogen addition while the exhaust CO and CO do not vary much with hydrogen addition. The exhaust NO increases with the advancing of ignition timing and the behavior tends to be more obvious at large ignition advance angle. The brake mean effective pressure and the effective thermal efficiency of natural gas/hydrogen mixture combustion increase compared with those of natural gas combustion when the hydrogen fraction is over 10%.
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Continuous deacylation of amides in a high-temperature and high-pressure microreactor

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1818-1825 doi: 10.1007/s11705-022-2182-y

摘要： The deacylation of amides, which is widely employed in the pharmaceutical industry, is not a fast reaction under normal conditions. To intensify this reaction, a high-temperature and high-pressure continuous microreaction technology was developed, whose space-time yield was 49.4 times that of traditional batch reactions. Using the deacylation of acetanilide as a model reaction, the effects of the temperature, pressure, reaction time, molar ratio of reactants, and water composition on acetanilide conversion were carefully studied. Based on the rapid heating and cooling capabilities, the kinetics of acetanilide deacylation at high temperatures were investigated to determine the orders of reactants and activation energy. This microreaction technology was further applied to a variety of other amides to understand the influence of substituents and steric hindrance on the deacylation reaction.

关键词： amide deacylation     microreactor     flow chemistry     reaction intensification    

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Terahertz time-domain spectroscopy of high-pressure flames

Jason BASSI, Mark STRINGER, Bob MILES, Yang ZHANG

《能源前沿（英文）》 2009年 第3卷 第2期   页码 123-133 doi: 10.1007/s11708-009-0033-x

摘要： Laser spectroscopy in the visible and near infrared is widely used as a diagnostic tool for combustion devices, but this approach is difficult at high pressures within a sooty flame itself. High soot concentrations render flames opaque to visible light, but they remain transparent to far-infrared or terahertz (THz) radiation. The first far-infrared absorption spectra, to the best of our knowledge, of sooty, non-premixed, ethylene high-pressure flames covering the region of 0.2-2.5 THz is presented. A specially designed high-pressure burner which is optically accessible to THz radiation has been built allowing flame transmission measurements up to pressures of 1.6 MPa. Calculations of the theoretical combustion species absorption spectra in the 0.2-3 THz range have shown that almost all the observable features arise from H O. A few OH (1.84 and 2.51 THz), CH (2.58 THz), and NH (1.77 and 2.95 THz) absorption lines are also observable in principle. A large number of H O absorption lines are observed in the ground vibrational in a laminar non-premixed, sooty flame (ethylene) at pressures up to 1.6 MPa.

关键词： terahertz time-domain spectroscopy     high-pressure flames     H2O absorption lines    

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A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

《机械工程前沿（英文）》 2009年 第4卷 第2期   页码 219-223 doi: 10.1007/s11465-009-0024-y

摘要： Based on structures and characteristics of traditional hydraulic pumps, this paper proposes a novel high-temperature and high-pressure hydraulic pump (HHHP) that can work under 150°C and 28 MPa to overcome problems of traditional high-temperature plunger pumps. The HHHP is designed with the structure of mechanical division and double cylinder parallel. The control signals of two cylinders are two separate triangle waveforms with 90° phase difference. Because the output waveforms of two cylinders have the same characteristics as the control signals, the HHHP can obtain a stable output after two separate waveforms are superposed. A mononeuron self-adaptive PID control algorithm is also improved by modifying parameters and . Two improved controllers are used to control the two cylinders, respectively, making two displacements of plungers match each other. Therefore, reduced fluctuations and stable pressure output is obtained. Besides simulation, tests on the built prototype test system are carried out to verify the performance of HHHP. Results show that the improved control approach can limit fluctuations to a lower level and the HHHP system attains good outputs under different signal periods and different pressures.

关键词： mononeuron PID control     hydraulic pump     pressure fluctuation    

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Numerical simulation of air flow field in high-pressure fan with splitter blades

LI Jianfeng, LU Junfu, ZHANG Hai, LIU Qing, YUE Guangxi

《能源前沿（英文）》 2008年 第2卷 第4期   页码 438-442 doi: 10.1007/s11708-008-0085-3

摘要： For a deeper understanding of the flow characteristics in the high-pressure centrifugal blower of a fan of Model 9-26 with splitter blades, a three dimensional (3-D) numerical simulation of air flows in the fan was conducted with FLUENT software. The standard - turbulent model and unstructured grids were used. The computational fluid dynamics (CFD) results showed that the performance of a fan could be improved by adding the splitter blades in the channel among the leaf blades. Under operational conditions, with the presence of splitter blades, the air flow rate of the fan increased about 5% and the total pressure at the outlet of the fan increased about 10% on average. It was also found that the length of the splitter blades affected the air flow and pressure drop. There is an optimal value for the length. The simulation results provide helpful information for improving the fan performance.

关键词： splitter     numerical simulation     presence     unstructured     operational    

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Spray characteristics of high-pressure swirl injector fueled with alcohol

WANG Xibin, CHEN Wansheng, GAO Jian, JIANG Deming, HUANG Zuohua

《能源前沿（英文）》 2007年 第1卷 第1期   页码 105-112 doi: 10.1007/s11708-007-0012-z

摘要： The spray characteristics of methanol and ethanol with high-pressure swirl injector were explored experimentally and numerically. Experimental results show that the spray characteristics of methanol and ethanol had displayed the same trends as that of gasoline. Under the low back-pressure ambient conditions, the spray behavior exhibited a hollow cone with wide spray angle and initial spray slug at the tip, while the spray presented a solid cone in the case of high back-pressure. Vortexes in the opposite direction existed in the rear part of the spray under low back-pressure ambient conditions while the vortexes formed in the middle part under high back-pressure ambient conditions. Experiments also showed that methanol had the largest cone angle, while ethanol and gasoline presented almost the same cone angle. Simulation results indicated that methanol and ethanol had a slightly larger Sauter mean diameter (SMD) than that of gasoline with swirl injector. The SMD profile of methanol coincided well with that of ethanol under low back-pressure ambient conditions, but displayed a slightly larger value under high back-pressure due to fuel evaporation. Numerical simulation could successfully demonstrate the spray characteristics of high-pressure swirl injector for methanol and ethanol fuels.

关键词： low back-pressure     diameter     initial spray     hollow     middle    

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Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

HUANG Yongcheng, WANG Shangxue, ZHOU Longbao

《能源前沿（英文）》 2008年 第2卷 第3期   页码 261-267 doi: 10.1007/s11708-008-0062-x

摘要： Effects of Fischer-Tropsch (F-T) diesel fuel on the combustion and emission characteristics of a single-cylinder direct injection diesel engine under different fuel delivery advance angles were investigated. The experimental results show that F-T diesel fuel exhibits shorter ignition delay, lower peak values of premixed burning rate, lower combustion pressure and pressure rise rate, and higher peak value of diffusion burning rate than conventional diesel fuel when the engine remains unmodified. In addition, the unmodified engine with F-T diesel fuel has lower brake specific fuel consumption and higher effective thermal efficiency, and presents lower HC, CO, NO and smoke emissions than conventional diesel fuel. When fuel delivery advance angle is retarded by 3 crank angle degrees, the combustion duration is obviously shortened; the peak values of premixed burning rate, the combustion pressure and pressure rise rate are further reduced; and the peak value of diffusion burning rate is further increased for F-T diesel fuel operation. Moreover, the retardation of fuel delivery advance angle results in a further significant reduction in NO emissions with no penalty on specific fuel consumption and with much less penalty on HC, CO and smoke emissions.

关键词： combustion pressure     further     HC     operation     single-cylinder    

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“高效两冲程发动机概念的更正：具有空气混合动力功能的增压单流扫气直喷汽油（BUSDIG）发动机” [工程5（2019）535–547]

Xinyan Wang, Hua Zhao

《工程（英文）》 2019年 第5卷 第5期   页码 979-979 doi: 10.1016/j.eng.2019.08.004

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Development of lunar regolith-based composite for - 3D printing via high-pressure extrusion system

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0745-8

摘要： To fully utilize the in-situ resources on the moon to facilitate the establishment of a lunar habitat is significant to realize the long-term residence of mankind on the moon and the deep space exploration in the future. Thus, intensive research works have been conducted to develop types of 3D printing approach to adapt to the extreme environment and utilize the lunar regolith for in-situ construction. However, the in-situ 3D printing using raw lunar regolith consumes extremely high energy and time. In this work, we proposed a cost-effective melting extrusion system for lunar regolith-based composite printing, and engineering thermoplastic powders are employed as a bonding agent for lunar regolith composite. The high-performance nylon and lunar regolith are uniformly pre-mixed in powder form with different weight fractions. The high-pressure extrusion system is helpful to enhance the interface affinity of polymer binders with lunar regolith as well as maximize the loading ratio of in-situ resources of lunar regolith. Mechanical properties such as tensile strength, elastic modulus, and Poisson’s ratio of the printed specimens were evaluated systematically. Especially, the impact performance was emphasized to improve the resistance of the meteorite impact on the moon. The maximum tensile strength and impact toughness reach 36.2 MPa and 5.15 kJ/m2, respectively. High-pressure melt extrusion for lunar regolith composite can increase the effective loading fraction up to 80 wt.% and relatively easily adapt to extreme conditions for in-situ manufacturing.

关键词： in-situ resource utilization     melt extrusion molding     lunar regolith-based composites     mechanical properties     additive manufacturing    

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Performance and emission characteristics of QHCCI dimethyl ether engine

WANG Ying, LI Wei, ZHOU Longbao, LIU Shenghua, HU Tiegang

《能源前沿（英文）》 2008年 第2卷 第4期   页码 401-405 doi: 10.1007/s11708-008-0075-5

摘要： Experimental investigation into the effects of different pilot amounts of dimethyl ether (DME) on the performance and emission of a single-cylinder direct-injection DME engine is conducted. The results show that a DME engine can operate at a wider range of speeds and loads at quasi-homogenous charge compression ignition (QHCCI) mode. The brake thermal efficiency increases while the exhaust temperature decreases. NO emission decreases by about 30%–50% although there is a slight increase in HC and CO emissions. NO, HC and CO emissions increase with an increase in the amount of DME pilot. QHCCI is a good way to increase thermal efficiency and decrease NO emission.

关键词： Experimental investigation     single-cylinder direct-injection     exhaust temperature     dimethyl     compression ignition    

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and laboratory experimental studies on hard-rock tunnel excavation based on disc cutter coupled with high-pressure

《结构与土木工程前沿（英文）》   页码 1370-1386 doi: 10.1007/s11709-023-0947-0

摘要： The tunnel boring machine (TBM) is typically used in hard-rock tunnel excavation. Owing to the unsatisfactory adaptability of TBM to the surrounding rock, when crossing high-strength and high-wear strata, the TBM can easily cause defects, such as abnormal wear on cutters and overload damage to bearings, thus affecting the construction efficiency and cost. Therefore, high-pressure waterjet technology should be applied to assist in rock breaking for efficient TBM tunneling. In this study, the effects of water pressure, nozzle diameter, and nozzle speed on cutting are investigated via laboratory experiments of cutting hard rock using high-pressure waterjets. The penetration performance of the TBM under different water pressures is investigated via a field industrial penetration test. The results show that high-pressure waterjets are highly efficient for rock breaking and are suitable for industrial applications, as they can accommodate the advancing speed of the TBM and achieve high-efficiency rock breaking. However, during the operation of high-pressure waterjets, the ambient temperature and waterjet temperature in the tunnel increase significantly, which weakens the cooling effect of the cutterhead and decreases the construction efficiency of the TBM. Therefore, temperature control and cooling measures for high-pressure waterjets during their long-term operation must be identified. This study provides a useful reference for the design and construction of high-pressure water-jet-assisted cutterheads for breaking road headers.

关键词： tunnel boring machine     hard-rock cutting     free face     disc cutter     rock-cutting efficiency    

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Pilot study for the treatment of sodium and fluoride-contaminated groundwater by using high-pressure

Xiaomao WANG,Hongwei YANG,Zhenyu LI,Shaoxia YANG,Yuefeng XIE

《环境科学与工程前沿（英文）》 2015年 第9卷 第1期   页码 155-163 doi: 10.1007/s11783-014-0740-3

摘要： High-pressure membrane process is one of the cost-effective technologies for the treatment of groundwater containing excessive dissolved solids. This paper reports a pilot study in treating a typical groundwater in Huaibei Plain containing excessive sodium, sulfate and fluoride ions. Three membrane systems were set up and two brands of reverse osmosis (RO), four low-pressure RO (LPRO) and one tight nanofiltration (NF) membranes were tested under this pilot study. An apparent recovery rate at about 75% was adopted. Cartridge filtration, in combination with dosing antiscalent, was not sufficient to reduce the fouling potential of the raw water. All RO and LPRO systems (except for the two severely affected by membrane fouling) demonstrated similar rejection ratios of the conductivity (~98.5%), sodium (~98.5%) and fluoride (~99%). Membrane fouling substantially reduced the rejection performance of the fouled membranes. The tight NF membrane also had a good rejection on conductivity (95%), sodium (94%) and fluoride (95%). All membranes rejected sulfate ion almost completely (more than 99%). The electricity consumptions for the RO, LPRO and NF systems were 1.74, 1.10 and 0.72 kWh?m treated water, respectively. The estimated treatment costs by using typical RO, LPRO and tight NF membrane systems were 1.21, 0.98 and 0.96 CNY?m finished water, respectively. A treatment process consisting of either LPRO or tight NF facilities following multi-media filtration was suggested.

关键词： reverse osmosis (RO)     nanofiltration (NF)     water quality standards     sodium     fluoride     cost estimation    

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标题 作者 时间 类型 操作

Development of a simplified n-heptane/methane model for high-pressure direct-injection natural

Jingrui LI, Haifeng LIU, Xinlei LIU, Ying YE, Hu WANG, Xinyan WANG, Hua ZHAO, Mingfa YAO

期刊论文

Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

Yi REN,Xianguo LI

期刊论文

Combustion characteristics of a direct-injection diesel engine fueled with Fischer-Tropsch diesel

HUANG Yongcheng, ZHOU Longbao, PAN Keyu

期刊论文

of ignition timing and hydrogen fraction on combustion and emission characteristics of natural gas direct-injection

WANG Jinhua, HUANG Zuohua, LIU Bing, ZENG Ke, YU Jinrong, JIANG Deming

期刊论文

Continuous deacylation of amides in a high-temperature and high-pressure microreactor

期刊论文

Terahertz time-domain spectroscopy of high-pressure flames

Jason BASSI, Mark STRINGER, Bob MILES, Yang ZHANG

期刊论文

A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

期刊论文

Numerical simulation of air flow field in high-pressure fan with splitter blades

LI Jianfeng, LU Junfu, ZHANG Hai, LIU Qing, YUE Guangxi

期刊论文

Spray characteristics of high-pressure swirl injector fueled with alcohol

WANG Xibin, CHEN Wansheng, GAO Jian, JIANG Deming, HUANG Zuohua

期刊论文

Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

HUANG Yongcheng, WANG Shangxue, ZHOU Longbao

期刊论文

“高效两冲程发动机概念的更正：具有空气混合动力功能的增压单流扫气直喷汽油（BUSDIG）发动机” [工程5（2019）535–547]

Xinyan Wang, Hua Zhao

期刊论文

Development of lunar regolith-based composite for - 3D printing via high-pressure extrusion system

期刊论文

Performance and emission characteristics of QHCCI dimethyl ether engine

WANG Ying, LI Wei, ZHOU Longbao, LIU Shenghua, HU Tiegang

期刊论文

and laboratory experimental studies on hard-rock tunnel excavation based on disc cutter coupled with high-pressure

期刊论文

Pilot study for the treatment of sodium and fluoride-contaminated groundwater by using high-pressure

Xiaomao WANG,Hongwei YANG,Zhenyu LI,Shaoxia YANG,Yuefeng XIE

期刊论文