Ejector performance prediction at critical and subcritical operational modes

Li, Fenglei,Tian, Qi,Wu, Changzhi,Wang, Xiangyu,Lee, Jae-Myung Pergamon 2017 Applied thermal engineering Vol. No.

<P><B>Abstract</B></P> <P>Traditional ejector models are focusing on the ejector performance predictions at critical mode under design conditions. In reality, ejector systems cannot be operated under these conditions perfectly. Thus, the study of ejector performance at subcritical mode under off-design conditions is important. In this paper, novel models for ejector performance predictions at critical point and breakdown point are developed based on constant-pressure mixing and constant-pressure disturbing assumptions. Then, the two models are integrated as the model to predict ejector performance at critical and subcritical operational modes. In order to determine the ejector component efficiencies in the models, a novel concept, the effect of the change (EOC) of efficiency, is introduced to identify the efficiencies which affect ejector performance significantly. Then, the identified efficiencies are determined by sparsity-enhanced optimization method. The predicted results obtained by our model are much more accurate than those obtained by existing methods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel models for ejector performance analysis at critical and breakdown points are developed. </LI> <LI> The models are integrated to predict ejector performance over entire operational range. </LI> <LI> An analysis method is developed for identifying the ejector component efficiencies. </LI> <LI> The performance prediction errors over entire operational range are within ±10%. </LI> </UL> </P>

IMPACTS OF WATER AND SEDIMENT LOAD CHANGE ON DEVELOPMENT OF MEANDERS IN LOWER YELLOW RIVER

CHANGZHI LI,ZHAOYIN WANG,JING ZHOU,JIXIANG LIU 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Incremental gradient-free method for nonsmooth distributed optimization

Li, Jueyou,Li, Guoquan,Wu, Zhiyou,Wu, Changzhi,Wang, Xiangyu,Lee, Jae-Myung,Jung, Kwang-Hyo AMERICAN INSTITUTE OF MATHEMATICAL SCIENCES 2017 JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION Vol. No.

Numerical and experimental verifications on damping identification with model updating and vibration monitoring data

Li, Jun,Hao, Hong,Fan, Gao,Ni, Pinghe,Wang, Xiangyu,Wu, Changzhi,Lee, Jae-Myung,Jung, Kwang-Hyo Techno-Press 2017 Smart Structures and Systems, An International Jou Vol.20 No.2

Identification of damping characteristics is of significant importance for dynamic response analysis and condition assessment of structural systems. Damping is associated with the behavior of the energy dissipation mechanism. Identification of damping ratios based on the sensitivity of dynamic responses and the model updating technique is investigated with numerical and experimental investigations. The effectiveness and performance of using the sensitivity-based model updating method and vibration monitoring data for damping ratios identification are investigated. Numerical studies on a three-dimensional truss bridge model are conducted to verify the effectiveness of the proposed approach. Measurement noise effect and the initial finite element modelling errors are considered. The results demonstrate that the damping ratio identification with the proposed approach is not sensitive to the noise effect but could be affected significantly by the modelling errors. Experimental studies on a steel planar frame structure are conducted. The robustness and performance of the proposed damping identification approach are investigated with real measured vibration data. The results demonstrate that the proposed approach has a decent and reliable performance to identify the damping ratios.

Numerical Investigations of Collision Modes of Double Droplets on a Spherical Surface Based on the Phase Field Method

Jiang Changzhi,Wang Zhaohui,Yang Qianwen,Gao Quanjie,Li Deli 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.6

Droplet collision on surface is widely existed in nature and industrial production. In our research, two-dimensional rotational models and three-dimensional symmetric models based on the phase fi eld method have been developed to simulate the collisions of continuous droplets on spherical surfaces. Using parametric dimensionless, the spreading diameter of the coalescing droplets, the width of the liquid bridge between the droplets, and the moving velocity of the three-phase contact line are obtained. When the two droplets are coaxial, the collision velocity of the droplets increases, and the radial velocity of the liquid bridge also increases. Due to the increase of droplet energy, both the fi rst and second maximum spreading are increased, but the characteristic spreading t s time is reduced. When using the modifi ed capillary inertia time ′ i normalized spreading time t s , it is found that it fi ts well with the Weber number (We) by the curve 1.505 We −0.478 . Increasing the ratio of curved surface to droplet diameter λ can reduce maximum spreading time and maximum rebound height of droplet. When there is a deviation between the centers of the droplets, the spread of the droplets no longer shows symmetry and the center of the condensed droplets moves towards the off set side of the tail droplets. These fi ndings will provide insight into the dynamics of continuous droplet collisions.

Numerical and experimental verifications on damping identification with model updating and vibration monitoring data

Jun Li,Hong Hao,Gao Fan,Pinghe Ni,Xiangyu Wang,Changzhi Wu,이제명,정광효 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.2

Identification of damping characteristics is of significant importance for dynamic response analysis and condition assessment of structural systems. Damping is associated with the behavior of the energy dissipation mechanism. Identification of damping ratios based on the sensitivity of dynamic responses and the model updating technique is investigated with numerical and experimental investigations. The effectiveness and performance of using the sensitivity-based model updating method and vibration monitoring data for damping ratios identification are investigated. Numerical studies on a three-dimensional truss bridge model are conducted to verify the effectiveness of the proposed approach. Measurement noise effect and the initial finite element modelling errors are considered. The results demonstrate that the damping ratio identification with the proposed approach is not sensitive to the noise effect but could be affected significantly by the modelling errors. Experimental studies on a steel planar frame structure are conducted. The robustness and performance of the proposed damping identification approach are investigated with real measured vibration data. The results demonstrate that the proposed approach has a decent and reliable performance to identify the damping ratios.

Enrichment of C17:0-rich saturated fatty acids from sheep tail fat for adjuvant therapy of non-small-cell lung cancer

Xiaoqi Yu,Xiaoyi Liu,Yuanli Li,Huimin He,Xinxin Pei,Tengfei Ma,Yuanyuan Chen,Yi Wang,Hongxia Li,Wenchu Lin,Changzhi Xu,Buchang Zhang 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.8

Heptadecanoic acid (C17:0), an odd-chain saturated fatty acid (OCSFA) in ruminant lipid, has been demonstrated to be potential for treating cancers. Our results also showed that sheep tail fat (STF) with higher level of C17:0-containing saturated fatty acids (SFAs) whereas lower level of oleic acid (C18:1), performed remarkable inhibition against non-small-cell lung cancer (NSCLC) cells. To enrich the content of C17:0, a C17:0-rich SFA concentrate (HRSC) was prepared from STF by solvent crystallization and urea complexation methods (hexane/STF = 3.5/1, 4 °C for 8 h, and 80% ethanol/urea/free fatty acids = 8/1/1, 4 °C for 6 h). The content of C17:0 was up from 3.02 to 6.34% and the recovery was 4.17%. Biological experiments showed that HRSC exerted better antiproliferative effect against NSCLC cells. Moreover, HRSC performed enhanced inhibitory effect in A549 cell xenograft mouse model. Therefore, HRSC has the potential to be applied in adjuvant therapy for NSCLC.

Dynamic and static structural displacement measurement using backscattering DC coupled radar

Shanyue Guan,Jennifer A. Rice,Changzhi Li,Yiran Li,Guochao Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.3

Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar’s measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.