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The 7th International Symposium on Measurement Techniques for multiphase flows

作者： Chen XiPing Yan JunJie Huang RongHai Liu JiPing State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao tong University

Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032 *** length,inter diameter of the tube was 110 mm,0.727 mm,*** tests were performed at a wide range of ethanol concentrations(Cv=0%,1%,2%,5%) and varied velocity of vapor(Uv=2m/s,4m/s,6m/s) and pressure(Pv=31.2kPa,47.4kPa,84.5kPa).With the change of the vapor-to-surface temperature difference,the heat transfer coefficients revealed nonlinear characteristics with the peak values under all ethanol mass fractions of *** heat transfer coefficients decreased with increasing ethanol mass fraction of vapor.

关键词： Condensation Drop Heat transfer mini-tube

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Numerical studies on natural circulation precooling loop of cryogenic liquid rocket engine

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Hangkong Dongli Xuebao/Journal of Aerospace power 2009年第3期24卷 698-704页

作者： Chen, Er-Feng Li, Yan-Zhong Cheng, Xiang-Hua School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

One set of one-dimensional unsteady homogenous mathematic models for flow and heat process of natural circulation precooling loop of cryogenic liquid rocket engine was established, whilst both inverted annular model and dispersed model were introduced for the prediction of filming boiling region. The results indicate the unstable characteristics of circulation flow rate in precooling process is caused by the unstable characteristics of natural circulation driving force, that is, the heat flux transferred to the cryogenic liquid from the natural circulation precooling loop. Moreover, about 80% of wall temperature drop takes place in filming boiling region, and the inverted temperature distribution law of the return pipe is well interpreted by introducing the two filming boiling models mentioned above.

关键词： Rockets

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Experimental and Numerical Investigations on Heat Transfer Characteristics of Supercritical Water in a Vertical Tube

SSRN

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SSRN 2024年

作者： Du, Xiaocheng An, Ning Wei, Ziyu Yang, Dong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Heat transfer performance of working medium is important for supercritical units. In this work, heat transfer experiments and simulations were carried out at 25 to 29.8 MPa. The impacts and influence mechanisms of operation parameters on heat transfer characteristics were analyzed. To describe the fluid heat storage capacity, a metric called cdv is proposed. The findings indicate that thermal conductivity, cdv, and flow turbulence intensity are the three types of factors influencing heat transfer characteristics. As mass flux rises, the radial flow turbulence intensity increases, leading to an improvement in heat transfer performance. The impact of heat flux is mainly showed in high enthalpy zone. Due to the reduction in radial thermal conductivity, heat transfer enhances as heat flux decreases. Large specific heat zone, where the thermophysical parameters vary quickly, are where the influence of pressure is most evident. Because of the high thermal conductivity and cdv, the heat transfer characteristics get better as pressure drops. Finally, typical heat transfer correlations were evaluated using experiment results. The Bishop, Mokry and Miropoiskii-Shitsman correlations exhibited relatively large errors, and the correlations proposed by Swenson and Jackson have a low error and are highly consistent with the experiment results. © 2024, The Authors. All rights reserved.

关键词： Heat flux

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Enhanced Photosynthetic Hydrogen Production of Rhodobacter sphaeroides with Deactivation of spbA and hupSL

Enhanced Photosynthetic Hydrogen Production of Rhodobacter s...

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第五届世界氢能技术大会(WHTC2013)

作者： Xueqing Wang Honghui Yang Yang Zhang Liejin Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi''an Jiaotong University China

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Exergy analysis of solar dynamic closed Brayton cycle for space applications

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Taiyangneng Xuebao/Acta Energiae Solaris Sinica 2010年第3期31卷 351-356页

作者： Chen, Shuangtao Hou, Yu Chen, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Exergy analysis of solar dynamic closed Brayton cycle (SDCBC) for space applications was presented in this paper. An integrated model for the system and specific models for its components were proposed. Influence of main parameters on system exergy efficiency was discussed. The results shown the efficiencies of expander, compressor, and regenerating temperature of the regenerator have significant influence on the exergy efficiency of SDCBC system. Therefore, besides the enhancement of component efficiencies, the matching among components of SDCBC system should be also taken into account. Moreover, it would be always desirable to enhance the effectiveness of recuperator within the requirements of flow resistance and system weight.

关键词： Space applications

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Theoretical Study on Photoacoustic Tweezers Based on Photo-Thermo-Acoustic-Mechanical Coupling Effects

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Zhongguo Jiguang/Chinese Journal of Lasers 2025年第9期52卷

作者： Lin, Zhanle Hu, Feifan Shan, Wanru Li, Dong Chen, Bin Zheng, Yuping Yao, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Department of Ophthalmology The Second Affiliated Hospital Xi’an Jiaotong University Shaanxi Xi’an710004 China

Objective Photoacoustic tweezers (PATs) are a promising noninvasive technology for precise microparticle manipulation that leverage the photoacoustic effect to exert controlled forces on particles within a liquid medium. Conventional methods, such as optical and acoustic tweezers, present limitations such as potential damage to particles, inadequate spatial control, and restricted manipulation in three-dimensional (3D) environments. Hence, this study focuses on the theoretical development of a PAT model that integrates photo-thermo-acoustic-mechanical coupling effects. Using a ring-shaped laser beam, this study aims to investigate particle motion and force characteristics under various laser conditions. Additionally, this study seeks to establish a robust theoretical framework for PATs, thus filling the gaps in 3D particle manipulation and providing guidance for the optimization of experimental parameters. Methods A multiphysics coupling model for PATs was constructed to describe the interactions among photo-thermal, acoustic, and mechanical effects in a liquid medium. The model accounts for the transformation of laser energy density into heat and the subsequent thermal expansion, and the generation of acoustic waves that induces acoustic radiation forces and acoustic streaming. A ring-shaped laser beam was employed to create spatially confined acoustic fields that can trap and manipulate particles. Using the finite-element method (FEM) in Comsol software, the model was used to simulate high-frequency pulsed laser effects, including energy transfer, thermal expansion, acoustic wave propagation, and the resultant particle dynamics. The governing equations for the coupled fields were derived by incorporating the spatial and temporal distributions of the laser, the thermal and acoustic properties of the medium, and force interactions on the particles. The acoustic radiation forces were modeled based on Gor’kov potential theory, whereas the acoustic streaming fields wer

关键词： Acoustic emissions

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Atmospheric Pb levels over Mount Qomolangma region

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Particuology 2009年第3期7卷 211-214页

作者： Renjian Zhang Zhenxing Shen Han Zou Key Labaratory of Regional Climate-Environment Research far Temperate East Asia (REC-TEA) Institute of Atmaspheric Physics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Multiphase Flaw in Power Engineering Deportment of Environmental Science and Engineering Xi'an Jiaotong University Xi'An 710049 China

The Pb spectral concentration of atmospheric aerosol samples observed over Mount Qomolangma site （28° 11＇33＂N, 86°49＇S9＂E, 4950m ASL） in 2002 was 13.3 ng/m^3, about 4.5 times higher than that in 2000. The Pb spectral distribution showed three peaks, located at 〈0.25 μm, 0.5-1 μm, and 4-8 μm in diameters. The peaks for 〈0.25 μm and 0.25-0.5 μm may be due to long-distant transport, while that for 4-8 μm probably results from local floating dust. The atmospheric Pb concentration over Mount Momolangma was lower than that of South Pole, most of the urban areas, and desert areas in the northern hemisphere. The enrichment factors for fine and coarse particles of atmospheric Pb in 2002 over Mount Qomolangma were 413.2 and 62,6, respectively, in support of the slight atmospheric pollution with Pb over the Qinghai- Tibetan Plateau.

关键词： Pb Mount Qomolangma Enrichment factor

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Experimental Study on Total Pressure Distribution for Sonic Submerged Steam Jet

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AIP Conference Proceedings 2010年第1期1207卷 386-390页

作者： D. D. Pan J. J. Yan G. Y. Liu aState Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Experiments on the condensation of steam jet submerged in the subcooled water were carried out. The water temperature and the inlet steam pressure were in the range of 293 K–343 K and 0.2–0.6 MPa, respectively. Four essential shapes of steam plume were enumerated. According to the comparisons of the pictures of steam plume with the graphs in the same size, the pressure came to maximum value in the contraction spots, except for the double expansion‐emanative shape. Moreover, pressure distributions of the flow field were characterized by means of drawing isobar. Comparison and discussions on the relationship between steam plume and pressure distributions were given. With the increase of temperature, pressure distributions within steam plume became more complex. Radial pressure distributions were classified according to different regions. Comparisons of the pressure distributions at different water temperature and inlet steam pressure were obtained.

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Laser-induced Morphology Change and Photo-thermolysis of Gold Nano Particles with Application in Laser Dermatology

Laser-induced Morphology Change and Photo-thermolysis of Gol...

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2017第六届国际新材料大会

作者： Bin Chen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China

Based on the principle of selective photothermolysis,laser photothermal therapy is regarded as the most effective treatment methodology for port-wine stain（PWS）,which is a congenital vascular malformation caused by the expansion of capillaries in the dermis.1064 nm Nd:YAG laser has great potential for the treatment of deeper and larger ***,the clinical effectiveness is limited because of the weak absorption of blood to Nd:YAG *** order to enhance the blood absorption,spherical gold nanoparticles were prepared by Sodium citrate reduction method with average size of 16.7 nm and absorbance peak at 522 *** nanorods were prepared by Seeded growth method and modified by PEG with average length and width of 79.1 nm and 13.5 *** this aspect ratio of 5.89,a strong absorption band at050 nm in the near-infrared range is *** can inject spherical gold particles into the bloodstream to enhance the light absorption of blood in visible range,while using gold nanorod to increase absorbance of blood to Nd:YAG Laser for improving the cure rate of laser treatment of vascular *** absorption was increased by 1.25 times for 581 nm（PDL laser） and 3.71 times for 1064 nm（Nd:YAG laser）.To investigate the morphology change and photothermolysis of gold NRs induced by Nd:YAG laser and obtain the optimal irradiation conditions for effectively destroying the vascular lesions,tissue-like phantoms were prepared and exposed to Nd:YAG laser with various laser parameters to investigate the photothermolysis of gold *** obtained the optimal photothermolysis of gold NRs for destroying the blood vessel as follows:When the concentration of gold NRs is 26.67 g/mL,the Nd:YAG laser energy density should be 40 J/cm2,with long laser pulse width of 0.3 ms for ten pulses.

关键词： Laser-induced Morphology Change and Photo-thermolysis of Gold Nano Particles with Application in Laser Dermatology

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Experimental study on the thermochemical reduction of supercritical CO2 by guaiacol

Experimental study on the thermochemical reduction of superc...

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International Multidisciplinary Conference on Computer and Energy Science (SpliTech)

作者： Yimeng Wei Jiadela Kuanibieke Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China

The continuous growth of CO 2 emissions is one of the global problems facing humanity, and how to convert and exploit the stock of CO 2 has become an urgent issue. Biomass as an activity of CO 2 thermal reduction medium has become the focus of human attention in general. Supercritical CO 2 (SCCO 2 ) has the advantages of near-liquid density and high solubility, which can further strengthen the reduction process (T≥31.26℃, P≥72.9 atm). This paper described a SCCO 2 reduction method of guaiacol on an intermittent Kettle Reactor to investigate the effects of reaction temperature (400-700℃), residence time (5-20 min) and reactant concentration (4 wt%-16wt%) on the three-phase products. The experimental results indicated that the carbon gasification efficiency (CE) and hydrogen gasification efficiency (HE) were 43.7% and 56.7%, respectively, when the carbon dioxide consumption reached 16.15 mol/kg. As the temperature increased, the consumption of carbon dioxide increased and the concentration of reactants increased with opposite results.

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