Long Ni

Optimizing Geometric Parameters in Hydrocyclones for Enhanced Separations: A Review and Perspective

Hydrocyclones have been extensively applied for solid–liquid or liquid–liquid separations in various industries. However, the exact mechanisms underlying the enhanced separation technologies based on the optimization of geometric parameters of hydrocyclones remain unclear, and a number of research teams have performed numerous studies to enlarge the application scope of hydrocyclones by optimizing geometric parameters. This review provides a comprehensive state-of-the-art review of hydrocyclone enhanced-separation technologies. The enhanced-separation technologies are categorized into ten groups: cylindrical section, inlet, vortex finder, underflow pipe, conical section, hydrocyclone inclination angle, hydrocyclone insertion, conical-section/apex water injection, reflux device, and multi-hydrocyclone arrangement. These enhanced-separation technologies were analyzed and summarized according to the key separation-performance parameters of hydrocyclones, such as separation efficiency, cut size, split ratio, energy consumption, and capacity. It is expected that both the reviewed contents and the proposed challenges and future methodologies and technologies may provide research fellows working in this field with an improved understanding of enhanced separation technologies of hydrocyclones.

Experimental study of the relationship between separation performance and lengths of vortex finder of a novel de-foulant hydrocyclone with continuous underflow and reflux function

ABSTRACT To solve the blockage and defer the fouling of sewage heat exchanger, a novel de-foulant hydrocyclone with continuous underflow and reflux function was proposed. Experimental results demonstrated that the novel hydrocyclone had a remarkable behavior on separating the sand (75–250 μm) and foulant (<4 mm). The continuous underflow and reflux function could significantly improve the separation efficiency by relieving the particle re-entrainment and eliminating the air core without increasing energy consumption (<17 kPa) and split ratio (<10%) considerably. Besides, the range of optimum vortex finder length was proportional to the particle density.

Performance improvement of water-cooled screw chiller under part load operation conditions by the paralleling throttle mechanism

Cur rently, wa ter-cooled screw chiller is widely ap plied in com mer cial and in dus trial build ings, and the en ergy con sump tion of wa ter chiller even could cover 70% of air-con di tion ing en ergy con sump tion in the most ad verse op er at ing con di tions. More over, a num ber of chill ers are run ning at a low rate un der part-load state. In or der to re duce the en ergy con sump tion of wa ter-cooled screw chill ers un der part-load state, the pa per pres ents the par al lel ing throt tle mech a nism. Through ex per i men tal study, un der part-load state, it can be found that the by-pass tube di am e ter Ø16 has the most pos i tive ef fect on the per for mance of wa ter-cooled screw chiller in four by-pass tube di am e ters. The oblique ac cess mode is better than the ver ti cal ac cess mode, while the spi ral ac cess mode has lit tle in flu ence on the chiller per for mance. Be cause of par al lel ing throt tle us ing, the exergetic loss of the evap o ra tor and chiller is able to be re duced by 3.4%-15.5% and 0-6.7%, re spec tively. Mean while, the co ef fi cient of per for mance of chiller can be en hanced by 0.2%-1.6%, and dis charge tem per a ture can be re duced by 0.4-2.7 °C. In ad di tion, the eco nomic and en vi ron men tal ben e fits of the ad vanced wa ter-cooled screw chiller are more ev i dent than the con ven tional wa ter-cooled screw chillers.

Research on the aquifer temperature field of Groundwater Heat Pump with Pumping & Recharging in the Same Well

Mathematical model of pumping and recharging well (PRW) for ground water heat pump(GWHP) was developed and two operating modes(one is operating only in winter and the other is continuous operating in winter and intermittent operating in summer) of the PRW in Shenyang for a office building was simulated and studied using the developed model. Simulation results showed that, when the GWHP operated only in winter, the largest temperature drop was about 8.3°C at the end of the first heating season. The temperature recovered only 1.2°C in the transition season when the heat pump stopped running and the groundwater will freeze in 2∼3 yeas if the system continuously running in operating only in winter mode. When the GWHP system runs in continuous operating in winter and intermittent operating in summer mode, the aquifer composed of temperature drop zone and the temperature raise zone, and the largest temperature drop and raise was about 4.5°C and 3.6°C respectively at the end of first running year. With the running of the ground water heat pump, the temperature drop zone enlarged gradually, while the temperature raise zone gradually shrunk. At the end of the fifth heating season, the temperature raise zone disappeared, the temperature drop of the aquifer was 7.5°C and the influence radius of PRW was about 58 m. It can be concluded that when the ground water heat pump operates in severe cold region, where the building heating and cold load was highly unbalanced, it was necessary to take varied seasonal thermal energy storage measures.