Measurement and analysis of the internal flow field in the hydrodynamic torque converter with adjustable guide vanes

This article presents a particle-tracking velocimetry experiment for studying internal flows of hydrodynamic torque converter whose guide vanes are adjustable. The torque converter in which the flow region is an enclosed space with multiple impellers has a complicated geometry of impellers. Complex flows in adjustable stator are experimentally analyzed using particle-tracking velocimetry, and some advanced measurement technique has been successfully applied. Under each opening, using the single-frame and triple-exposure method, images of the flow fields in the adjustable stator were recorded at three typical working conditions as the speed ratios were equal to 0 (stall), 0.5 (design), and 1 (idle). According to particle trajectories on the images, the displacements and corresponding velocity vectors were obtained. The internal flow pattern of the hydrodynamic torque converter with adjustable guide vanes were acquired and analyzed in two cases: the changing conditions under the same opening and the changing openings under the same condition

Mathematical Model for Elliptic Torus of Automotive Torque Converter and Fundamental Analysis of Its Effect on Performance

Passenger car torque converters have been designed with an increasingly flatter profile in recent years for the purpose of achieving a weight saving and more compact size. However, a flatter design tends to result in the reduced hydrodynamic performance. To improve its performance, a new flat torus of elliptic type method concentrating on the solution to flat TC was put forward, and four torque converters of different flatness ratios were designed to judge the superiority of the flat torus design method. The internal flow characteristics were numerically investigated using CFD codes and resulted in good agreement with experimental data. The results indicate that the main cause of this performance degradation can be attributed to deterioration of the velocity fields of the pump, and a case of flatness ratio 0.8 illustrates the reason that the performance designed by the flat torus design method based on the elliptic shape is more excellent than that of the traditional one. Furthermore, this study proposed a structure of removal of inner ring to improve the performance of torque converter

Drag Reduction and Performance Improvement of Hydraulic Torque Converters with Multiple Biological Characteristics

Fish-like, dolphin-like, and bionic nonsmooth surfaces were employed in a hydraulic torque converter to achieve drag reduction and performance improvement, which were aimed at reducing profile loss, impacting loss and friction loss, respectively. YJSW335, a twin turbine torque converter, was bionically designed delicately. The biological characteristics consisted of fish-like blades in all four wheels, dolphin-like structure in the first turbine and the stator, and nonsmooth surfaces in the pump. The prediction performance of bionic YJSW335, obtained by computational fluid dynamics simulation, was improved compared with that of the original model, and then it could be proved that drag reduction had been achieved. The mechanism accounting for drag reduction of three factors was also investigated. After bionic design, the torque ratio and the highest efficiencies of YJSW335 were both advanced, which were very difficult to achieve through traditional design method. Moreover, the highest efficiency of the low speed area and high speed area is 85.65% and 86.32%, respectively. By economic matching analysis of the original and bionic powertrains, the latter can significantly reduce the fuel consumption and improve the operating economy of the loader

Characteristics of Natural Ti-Bearing Nanoparticles in Groundwater within Karst Areas of Northern China

Karst areas are widespread in China and can be divided into southern karst and northern karst based on the geographical boundary of Qinling Mountains and Huaihe River. In northern karst regions, karst springs are the predominant landform. Previous studies on karst springs have predominantly focused on macroscopic perspectives, such as water chemistry characteristics, with less attention given to the microscopic characteristics of springs. Therefore, this study focused on the Jinan Baotu Spring area, representative of a typical northern karst region, and investigated the natural nanoparticles present in different aquifers at various depths from a microscopic point of view. Through the observation of nanoparticle tracking analyzer (NTA), numerous nanoparticles were identified in the groundwater samples. The particle size range of the particles contained in groundwater is mainly concentrated in the range of 150–500 nm, and the particle concentration is mainly concentrated in the range of 1.5–5.0 × 105 Particles/L. The microstructure, chemical composition, and element distribution of these nanoparticles were analyzed using TEM-EDS techniques. The results unveiled the presence of Ti-bearing nanoparticles in various groundwater layers, including both crystalline and amorphous states, as well as nanoparticles exhibiting the coexistence of crystal and amorphous structures. By comparing the measured lattice spacing with PDF cards, the crystalline Ti-bearing nanoparticles were identified as rutile, brookite, anatase, ilmenite, pseudorutile, and ulvospinel. Furthermore, the main components of the amorphous Ti-bearing nanoparticles predominantly consisted of Ti or a mixture of Ti and Fe. EDS analysis further indicated that the Ti-bearing nanoparticles carried additional metal elements, such as Zn, Ca, Mn, Mo, Cr, and Ni, suggesting their potential role as carriers of metal elements during groundwater transportation. This discovery provided new insights into the migration of metal elements in groundwater and underscores the capacity of nanoparticles to enhance the mobility of inorganic substances within the water environment. Notably, brookite was detected in three different areas, including the direct discharge area, indirect recharge area, and discharge area, which may indicate that some special natural nanoparticles could serve as natural mineral tracer particles in the process of groundwater migration

Hydrogeochemical Characteristics and Evolution Processes of Karst Groundwater Affected by Multiple Influencing Factors in a Karst Spring Basin, Eastern China

Karst groundwater is an important water supply, especially in northern China. With the rapid development of China’s economy, anthropogenic activities have had a significant impact on karst groundwater formation, circulation and other processes. In this paper, the Baotu spring basin, which is closely related to anthropogenic activities, was selected as the research object to carry out a study of water chemical characteristics and evolutionary processes. And, mathematical statistics, Piper trilinear diagram, Gibbs diagram, and ion ratio methods were used to analyze the characteristics and evolution processes of groundwater. The results of this study show that the hydrogeochemical components of karst groundwater are mainly controlled by the weathering of rocks, mainly by the dissolution of carbonate rocks and silicates with the dominant cation of Ca2+ and the dominant anion of HCO3−. Considering the role of anthropogenic activities, including agricultural and industrial activities, the evolution process of karst groundwater is mainly controlled by hydrogeochemical effects such as mineral dissolution and filtration, the mixing of multiple water bodies, anthropogenic activities (domestic sewage, industrial and agricultural wastes), oxidation–reduction and cation alternating adsorption. Moreover, the influence of anthropogenic activities on the formation and evolution of karst groundwater gradually increases, leading to the rise in nitrate content in karst groundwater and accelerating carbonate rock dissolution. The research results of this paper can provide a favorable reference for environmental protection and research on karst groundwater in areas of intensive anthropogenic activity

Characteristics and Controlling Factors of Groundwater Hydrochemistry in Dongzhi Tableland Area of the Loess Plateau of Eastern Gansu—A Case Study of Ning County Area, North China

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater were determined by using statistical analysis, hydrochemical methods, and hydrogeochemical simulation. The results indicated that the groundwater in the NCA was alkaline as a whole, and the average pH values of LPW and BPW were 8.1 and 7.8, respectively. The mean values of TDS concentrations of LPW and BPW were 314.9 mg/L and 675.3 mg/L, and the mean values of TH contents were 194.6 mg/L and 286.6 mg/L, respectively, which were mainly divided into hard fresh water. The Piper diagram illustrated that the hydrochemical type of groundwater in the NCA was mainly the HCO3·Ca type. The main recharge source of groundwater was atmospheric precipitation, and it was affected by evaporation to a certain extent. The linear relationships of δ18O and δ2H of LPW and BPW were δ2H = 6.998δ18O − 3.802 (R2 = 0.98) and δ2H = 6.283δ18O − 10.536 (R2 = 0.96), respectively. Hydrochemical analysis indicated that the groundwater in the NCA was mainly controlled by rock weathering and cation exchange. BPW was affected by the dissolution of gypsum. The possible mineral phases were identified on the basis of the main soluble minerals in the aquifer, and hydrogeochemical reverse simulations were performed. The dissolution of calcite, illite, and hornblende, and the precipitation of dolomite, plagioclase, and microcline occurred on both the LPW and BPW pathways

Characteristics and Controlling Factors of Groundwater Hydrochemistry in Dongzhi Tableland Area of the Loess Plateau of Eastern Gansu—A Case Study of Ning County Area, North China

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater were determined by using statistical analysis, hydrochemical methods, and hydrogeochemical simulation. The results indicated that the groundwater in the NCA was alkaline as a whole, and the average pH values of LPW and BPW were 8.1 and 7.8, respectively. The mean values of TDS concentrations of LPW and BPW were 314.9 mg/L and 675.3 mg/L, and the mean values of TH contents were 194.6 mg/L and 286.6 mg/L, respectively, which were mainly divided into hard fresh water. The Piper diagram illustrated that the hydrochemical type of groundwater in the NCA was mainly the HCO3·Ca type. The main recharge source of groundwater was atmospheric precipitation, and it was affected by evaporation to a certain extent. The linear relationships of δ18O and δ2H of LPW and BPW were δ2H = 6.998δ18O − 3.802 (R2 = 0.98) and δ2H = 6.283δ18O − 10.536 (R2 = 0.96), respectively. Hydrochemical analysis indicated that the groundwater in the NCA was mainly controlled by rock weathering and cation exchange. BPW was affected by the dissolution of gypsum. The possible mineral phases were identified on the basis of the main soluble minerals in the aquifer, and hydrogeochemical reverse simulations were performed. The dissolution of calcite, illite, and hornblende, and the precipitation of dolomite, plagioclase, and microcline occurred on both the LPW and BPW pathways