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Experimental Study on Diesel Spray and Flame Asymmetry Characteristics of Dual-Orifice Nozzles for a Medium-Speed Engine

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Journal of Thermal Science 2025年第1期 303-322页

作者： ju Dehao liu Rui ZHENG Liang DENG Jiahui ZHANG Wenzheng HUO Jinlu HUANG Li Shanghai Marine Diesel Engine Research Institute National Key Laboratory of Marine Engine Science and Technology Key Laboratory for Power Machinery and Engineering Ministry of EducationShanghai Jiao Tong University

The asymmetry of the multi-orifice spray will cause uneven heat load of the marine diesel engine,thereby affecting its working performance and service ***,an in-depth understanding of the spray and flame characteristics of multi-orifice nozzles will guide the optimization of the nozzle structure,needle design and diesel atomization and combustion *** this reason,four groups of dual-orifice nozzles with different hole diameters(0.1-0.55 mm) and mass flow rates covering the typical marine medium-speed diesel injections are designed and customized,and the constant volume chamber(CVC) with high temperature and pressure is used to simulate the actual in-cylinder working conditions of the diesel engine for the spray visualization *** study the asymmetry of the fuel sprays discharged from a diesel injector,the multi-orifice nozzle is simplified as a dual-orifice nozzle in this *** with X-ray Computed Tomography(CT) imaging technology,the influences of the nozzle internal structure on the spray and flame asymmetry are studied in the constructed supercritical *** is found that the asymmetry of the inlet angle and the equivalent length-diameter ratio is positively correlated with the inconsistency of the dual *** an increase in the injection pressure and nozzle diameter,the asymmetry of the dual spray becomes more pronounced,resulting in greater disparities in the ignition delay times and ignition positions of the two ***,the increase in nozzle diameter also leads to combustion instability,resulting in a flame with a serrated *** the increase of ambient temperature,the proportion of liquid phase in the jet decreases and the relative density of spray front decreases.

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Porosity of crushed rock layer and its impact on thermal regime of Qinghai-Tibet Railway embankment

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Journal of Central South University 2017年第4期24卷 977-987页

作者： liu ming-hao LI Guo-yu NIU Fu-jun LIN Zhan-ju LIN Zhan-ju State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences School of Resources and Environment University of Chinese Academy of Sciences

It has been proven that crushed rock layers used in roadbed construction in permafrost regions have a cooling effect. The main reason is the existence of large porosity of the rock layers. However, due to the strong winds, cold and high radiation conditions on the Qinghai-Tibet Plateau(QTP), both wind-blown sand and/or weathered rock debris blockage might reduce the porosity of the rock layers, resulting in weakening the cooling effect of the crushed rock layer(CRL) in the crushed rock embankment(CRE) of the Qinghai-Tibet Railway(QTR) in the permafrost regions. Such a process might warm the underlying permafrost, and further lead to potential threat to the QTR's integrity and stability. The different porosities corresponding to the different equivalent rock diameters were measured in the laboratory using water saturation method, and an empirical exponential equation between porosity and equivalent rock diameter was proposed based on the measured experimental data and an important finding is observed in our and other experiments that the larger size crushed rock tends to lead to the larger porosity when arbitrarily packing. Numerical tests were carried out to study impacts of porosity on permafrost degradation and differential thaw depths between the sunny and shady shoulders. The results show that the decrease in porosity due to wind-blown sand or weathered rock debris clogging can worsen the permafrost degradation and lead to the asymmetric thermal regime. In the traditional embankment(without the CRL within it), the largest differential thaw depth can reach up to 3.1 m. The optimized porosity appears in a range from 34% to 42% corresponding to equivalent rock diameter from 10 to 20.5 cm. The CRE with the optimized porosities can make underlying permafrost stable and 0 ℃ isotherms symmetric in the coming 50 years, even under the condition that the climate warming can lead to permafrost degradation under the CRE and the traditional embankment. Some practical implica

关键词： Qinghai-Tibet Railway crushed rock embankment porosity wind-blown sand permafrost degradation

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Temporal evidence combination method for multi-sensor target recognition based on DS theory and IFS

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1114-1125页

作者： ju Wang Fuxian liu Air and Missile Defense College Air Force Engineering University Xi’an 710051 China

In order to effectively deal with the conflict temporal evidences without affecting the sequential and dynamic characteristics in the multi-sensor target recognition(MSTR) system at the decision making level, this paper proposes a Dempster-Shafer(DS) theory and intuitionistic fuzzy set(IFS) based temporal evidence combination method(DSIFS-TECM). To realize the method,the relationship between DS theory and IFS is firstly analyzed. And then the intuitionistic fuzzy possibility degree of intuitionistic fuzzy value(IFPD-IFV) is defined, and a novel ranking method with isotonicity for IFV is proposed. Finally, a calculation method for relative reliability factor(RRF) is designed based on the proposed ranking method. As a proof of the method, numerical analysis and experimental simulation are performed. The results indicate DSIFS-TECM is capable of dealing with the conflict temporal evidences and sensitive to the changing of time. Furthermore, compared with the existing methods, DSIFS-TECM has stronger ability of anti-interference.

关键词： Dempster-Shafer(DS) theory intuitionistic fuzzy set(IFS) temporal evidence combination relative reliability factor

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Isoparametric Hypersurfaces Induced by Navigation in Lorentz Finsler Geometry

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Acta Mathematica Sinica,English Series 2023年第8期39卷 1547-1564页

作者： ming XU ju TAN Na XU School of Mathematical Sciences Capital Normal UniversityBeijing 100048P.R.China School of Microelectronics and Data Science Anhui University of TechnologyMaanshan 243032P.R.China

Using a navigation process with the datum(F,V),in which F is a Finsler metric and the smooth tangent vector field V satisfies F(−V(x))>1 everywhere,a Lorentz Finsler metric F˜can be *** functions and isoparametric hypersurfaces with or without involving a smooth measure can be defined for F˜.When the vector field V in the navigation datum is homothetic,we prove the local correspondences between isoparametric functions and isoparametric hypersurfaces before and after this navigation *** these correspondences,we provide some examples of isoparametric functions and isoparametric hypersurfaces on a Funk space of Lorentz Randers type.

关键词： Finsler metric homothetic vector field isoparametric function isoparametric hypersurface Lorentz Finsler metric Zermelo navigation

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Data-driven spatiotemporal projections of shallow permafrost based on CMIP6 across the Qinghai‒Tibet Plateau at 1 km^(2) scale

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Advances in Climate Change Research 2021年第6期12卷 814-827页

作者： YIN Guo-An NIU Fu-jun LIN Zhan-ju LUO Jing liu ming-Hao liu State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

The degradation of near-surface permafrost under ongoing climate change on the Qinghai‒Tibet Plateau (QTP) is of growing concern due to its impacts on geomorphological and ecological processes, as well as human activities. There is an increased need for an in-depth understanding of the evolution of permafrost temperature (Ttop) and active-layer thickness (ALT) at a fine scale on the QTP under climate change. This study evaluated the permafrost thermal development over the QTP for the period 1980–2100 at a 1 km^(2) scale using a physically analytical model accounting for both climatic and local environmental factors based on multi-source data. The model results were validated against thermal borehole measurements and baseline maps. The modeled current (2001–2018) permafrost area (Ttop ≤ 0 ℃) covers 1.42 × 10^(6) km^(2) (ca. 56.1% of the QTP land area), 10.1% of which thawed over the historical period 1981–2000. To assess how the ground thermal regime could develop in the future, we utilized the multi-model ensemble mean of downscaled outputs from eight climate models under three Shared Socio-economic Pathways (i.e., SSP126, 245, and 585) in CMIP6 to force the permafrost model. Model results suggest that the current (2001–2018) permafrost extent is likely to dramatically contract in the future period (2021–2100), as indicated by consistent Ttop warming and ALT increasing due to climate changing. About 26.9%, 59.9%, 80.1% of the current permafrost is likely to disappear by the end of the 21st century under SSP126, SSP245, and SSP585 scenarios, respectively. The simulation results may further provide new opportunities to assess the future impacts of climate warming on environments and engineering development over the QTP.

关键词： Climate change Analytical model Permafrost degradation Active-layer CMIP6 Qinghai‒Tibet Plateau(QTP)

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A review of carbonates as hydrocarbon source rocks: basic geochemistry and oil–gas generation

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Petroleum Science 2019年第4期16卷 713-728页

作者： liu-Wen Xia Jian Cao ming Wang ju-Lei Mi Ting-Ting Wang MOE Key Laboratory of Surficial Geochemistry School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023JiangsuChina Research Institute of Experiment and Testing PetroChina Xinjiang Oilfield CompanyKaramay 834000XinjiangChina

Carbonates have been known to act as hydrocarbon source rocks, but their basic geochemical and associated hydrocarbon generation characteristics remain not well understood as they occur with argillaceous source rocks in most cases, and the hydrocarbon generation from each rock type is di cult to distinguish, forming one of puzzling issues within the field of petroleum geology and geochemistry. To improve the understanding of this critical issue, this paper reviews recent advances in this field and provides a summary of key areas that can be studied in future. Results show that carbonate source rocks are generally associated with high-salinity environments with low amounts of terrestrial inputs and low dissolved oxygen contents. Petrographically, these source rocks are dark gray or black, fine-grained, stratified, and contain bacterial and algal bioprecursors along with some other impurities. They generally have low organic matter contents, although these can vary significantly in di erent cases(e.g., the total organic carbon contents of marine and lacustrine carbonate source rocks in China are generally 0.1%–1.0% and 0.4%–4.0%, respectively). These rocks contain type I and type II kerogen, meaning there is a lack of vitrinites. This means that assessment of the maturity of the organic matter in these sediments needs to use non-traditional techniques rather than vitrinite reflectance. In terms of molecular geochemistry, carbonate source rocks have typical characteristics indicative of generally reducing and saline environments and lower organism-dominated bioprecursors of organic matter, e.g., high contents of sulfur compounds, low Pr/Ph ratios, and dominance of n-alkanes. Most of the carbonate source rocks are typically dominated by D-type organic facies in an oxidized shallow water mass, although high-quality source rocks generally contain A-and B-type organic facies in saline lacustrine and marine-reducing environments, respectively. The hydrocarbon generation mod

关键词： Saline lacustrine source rocks Carbonates Organic facies Hydrocarbon generation

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果胶酶催化条件探索及澄清果汁的研究

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吉林大学自然科学学报 1993年第2期 106-112页

作者：郭慧云张应玖于雷杨平曹文华王红梅刘宝琦徐坚平明炬刘兰英吉林大学分子生物学系长春130023

测定了黑曲霉JB513果胶酶催化果汁澄清的最适条件.并对影响果汁澄清的其它因素进行了考察,结果表明,适量的明胶可使果汁澄清的时间缩短;纤维素酶有利于果汁的澄清;金属离子Ca^(2+),Mg^(2+)对果胶酶有激活作用,Sn^(2+),Fe^(3+)对果胶酶... 详细信息

测定了黑曲霉JB513果胶酶催化果汁澄清的最适条件.并对影响果汁澄清的其它因素进行了考察,结果表明,适量的明胶可使果汁澄清的时间缩短;纤维素酶有利于果汁的澄清;金属离子Ca^(2+),Mg^(2+)对果胶酶有激活作用,Sn^(2+),Fe^(3+)对果胶酶有抑制作用.

关键词：果胶酶催化条件澄清果汁

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Synthesis and Structure of Bis[2,6-bis(2-pyridylamino)pyridinium] Tetrachlorocadmiumate(II)

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Chinese Journal of Structural Chemistry 2006年第6期25卷 714-718页

作者： ZHANG Min XIE Yong-Shu WEI Kai-ju liu Qing-Liang PENG Shie-ming Department of Chemistry University of Scienceand Technology of China i-lefei 230026 China Department of Chemistry National Taiwan University Taipei Taiwan

The title compound （H3tpda）2[CdCl4] （H2tpda = 2,6-bis（2-pyridylamino）pyridi-ne） was synthesized by the reaction of CdCl2 with H2tpda in methanol under acidic condition. Singlecrystal X-ray analysis reveals that the compound crystallizes in monoclinic, space group P21/n with a = 13.377（3）, b = 16.978（3）, c = 14.328（3） A, β = 94.75（3）°, V = 3243.1（11） A^3, Z = 4, De = 1.603 g/cm^3,μ = 1.042 mm^-1, F（000） = 1576, C30H28CdCl4N10, Mr = 782.82, T = 291（2） K, R = 0.0433 and wR = 0.0848 for observed 4554 reflections with I 〉 2σ（I）. The cadmium（Ⅱ） atom in the complex anion is tetrahedrally coordinated by four chlorine atoms, whereas, in each [H3tpda]＋ cation, one pyridyl nitrogen is protonated. A 3D network is formed by multiple intermolecular hydrogen bonds between the cations and anions as well as π-π interactions among the pyridyl rings.

关键词： crystal structure cadmium complex 3D network tripyridyldiamine

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Performance comparison of permafrost models in Wudaoliang Basin,Qinghai-Tibet Plateau,China

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Journal of Mountain Science 2016年第7期13卷 1162-1173页

作者： YIN Guo-an NIU Fu-jun LIN Zhan-ju LUO Jing liu ming-hao State Key Laboratory of Frozen Soils Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Knowledge of the spatial distribution of permafrost and the effects of climate on ground temperature are important for land use and infrastructure development on the Qinghai-Tibet Plateau(QTP). Different permafrost models have been developed to simulate the ground temperature and active layer thickness(ALT). In this study, Temperature at Top of Permafrost(TTOP) model, Kudryavtsev model and modified Stefan solution were evaluated against detailed field measurements at four distinct field sites in the Wudaoliang Basin to better understand the applicability of permafrost models. Field data from 2012 to 2014 showed that there were notable differences in observed ground temperatures and ALTs within and among the sites. The TTOP model is relatively simple, however, when driven by averaged input values, it produced more accurate permafrost surface temperature(Tps) than the Kudryavtsev model. The modified Stefan solution resulted in a satisfactory accuracy of 90%, which was better than the Kudryavtsev model for estimating ALTs. The modified Stefan solution had the potential of being applied to climate-change studies in the future. Furthermore, additional field investigations over longer periods focusing on hydrology, which has significant influence on permafrost thaw, are necessary. These efforts should employ advanced measurement techniques to obtain adequate and extensive local parameters that will help improve model accuracy.

关键词： Permafrost model Active layer thickness Soil freeze-thaw Soil temperature

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Variations in the northern permafrost boundary over the last four decades in the Xidatan region, Qinghai–Tibet Plateau

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Journal of Mountain Science 2018年第4期15卷 765-778页

作者： LUO Jing NIU Fu-jun LIN Zhan-ju liu ming-hao YIN Guo-an State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China South China Institute of Geotechnical Engineering School of Civil Engineering and Transportation South China University of Technology Guangzhou 510641 China

The distribution and variations of permafrost in the Xidatan region, the northern permafrost boundary of the Qinghai-Tibet Plateau, were examined and analyzed using ground penetrating radar(GPR), borehole drilling, and thermal monitoring data. Results from GPR profiles together with borehole verification indicate that the lowest elevation limit of permafrost occurrence is 4369 m above sea level in 2012. Compared to previous studies, the maximal rise of permafrost limit is 28 m from 1975 to 2012. The total area of permafrost in the study region has been decreased by 13.8%. One of the two previously existed permafrost islands has disappeared and second one has reduced by 76% in area during the past ~40 years. In addition, the ground temperature in the Xidatan region has increased from 2012 to 2016, with a mean warming rate of ~0.004℃ a^(-1) and ~0.003℃ a^(-1) at the depths of 6 and 15 m, respectively. The rising of permafrost limit in the Xidatan region is mainly due to globalwarming. However, some non-climatic factors such as hydrologic processes and anthropic disturbances have also induced permafrost degradation. If the air temperature continues to increase, the northern permafrost boundary in the Qinghai-Tibet Plateau may continue rising in the future.

关键词： Qinghai-Tibet Plateau Permafrost Climate warming Permafrost limit Ground penetrating radar Thermal monitoring.

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