Ring Vacuum Research Articles

Optimization of vacuum membrane distillation and advanced design of compact solar water heaters with heat recovery

With the escalating global population, freshwater scarcity has become a pressing challenge. To address this issue, this paper presents a novel compact solar water heater (CSWHT) system incorporating heat recovery and submerged-membrane filtration. The research aims to develop an efficient desalination method that reduces water production costs and maximizes output. The system comprises a feed storage tank, a vacuum membrane distillation (VMD) system positioned atop the submerged CSWHT, a liquid ring vacuum pump (LRVP) utilizing waste heat from the outlet to preheat the feed, and hollow fiber membranes.Three critical parameters, namely the mass of the feed in the storage tank, the number of hollow fiber membrane rows, and the feed volumetric flow rate, were optimized using a multi-objective non-dominated sorting genetic algorithm II (NSGA II) to minimize water production cost (WPC) while maximizing water production. Subsequently, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was employed to identify the optimal scenario from among the selected best solutions.For Mediterranean seawater and a 6 m2 solar collector area, the multi-objective NSGA II algorithm identified 20 membrane rows per collector, 334.4 kg feed mass in the storage tank, and 0.027 kg.s−1 feed mass flow rate as the optimal system parameters. Under these optimized conditions, the system exhibited a daily production capacity of 92.5 kg water, 4.6 kg chloride, and 0.03 g bromide, while achieving a production cost of 12.2 USD.m−3 and a gain output ratio (GOR) of 1.6. These results highlight the system's remarkable potential for desalination with high efficiency and low cost. Future research should focus on scaling up the system and exploring its applicability in various geographical locations.

Synthesis and characterization of MWCNTs nanocomposite for fabrication of tensometric transducers

A nanocomposite was prepared using MWCNTs and micro-sized bronze particles dispersed in elastomer silicone organic compound (SILAGER 8030). The nano-composite was characterized by FT-IR, SEM, EDS and Raman spectroscopy; showing the rough surface of the composite with interweaving of nano threads. This nano-composite was used to manufacture strain gauge. The conductivities were measured concerning wt% of micro-sized bronze, compression and time. The maximum electrical conductivity obtained was 2.1 S/m at 5.0 wt% bronze metal alloy and MWCNT (3.0 wt%) at 16% compression. With increasing amplitude and frequency of ultrasonic exposure, an increase in the pressure associated with cavitation in the liquid was observed. Each value of ultrasound exposure corresponded to a certain value of electrical resistance. At the same time, with an increase in the intensity of the cavitation effect on the strain gauge transducer, extremum points appeared, which corresponded to a decrease in resistance. The developed material is highly useful for manufacturing strain gauges to be used in liquid ring vacuum pumps as a measuring transducer of liquid ring pressure into signals associated with changes in resistance. This allows liquid ring vacuum pumps to be precisely controlled; improving their energy efficiency and reliability.

Effect of temperature on the drag reduction characteristics of xanthan gum in the liquid ring vacuum pump

Xanthan gum (XG) solution has been proven to be an effective working fluid in the liquid ring vacuum (LRV) pump to achieve significant energy savings. As an important influencing factor of the LRV pump performance, the effect of temperature on the drag reduction performance, rheological properties, and microstructure of XG solution in the LRV pump were experimentally investigated in this paper. The results indicate that with the increase of temperature, the drag reduction rate of the XG solution in the LRV pump initially rise and subsequently decline, and XG solutions with different concentrations show different optimal drag reduction temperatures. The microscopic parallel double-chain structure of XG has the same change pattern as the drag reduction performance, while the steady-state and dynamic shear characteristics of the XG solution manifest a downtrend. For instance, as the temperature of 4000 ppm XG solution increases from 10 °C to 60 °C, the drag reduction rate decreases by 20 %; the parallel double-chain structure decreases from 91.3 % to 89.9 %; the yield stress and relaxation time decrease from 4.63993 Pa to 4477.56 s to 3.37808 Pa and 143.27 s, respectively; the drag reduction rate reaches the maximum value when the temperature is 40 °C.

Finite Element Analysis for NEG coated vacuum chamber based on ANSYS Workbench

The Hefei Advanced Light Facility (HALF) is a diffraction limited storage ring (DLSR) being constructed. As the main component of the storage ring vacuum system, the vacuum chamber transports the beam and withstands the thermal effect of synchrotron radiation simultaneously. The thermal and mechanical condition of the vacuum chamber of HALF were quantitatively analysed by means of ANSYS Workbench in this work. Combining the Computational Fluid Mechanics (CFD) and Finite Elements Analysis (FEA), the temperature and thermal stress maps of the vacuum chamber were calculated. The CFD calculation displays that the heat transfer coefficient between the water and the chamber is 7966-13093 W/(m2·°C). The thermal-mechanical simulation shows that the maximum temperature and thermal stress are 53.5 °C and 42.1 MPa, respectively. The static structural analysis was performed on vacuum chamber under the ultra-high vacuum condition, with the maximum stress of 1.7 MPa and the maximum deformation of 0.0003 mm. These results show that the vacuum chamber meets the design requirements and provide a critical theoretical basis for the design of the vacuum system of HALF.

ЖИДКОСТНОКОЛЬЦЕВЫЕ ВАКУУМНЫЕ НАСОСЫ КОМБИНИРОВАННОГО ТИПА ДЛЯ ЭНЕРГОЭФФЕКТИВНЫХ ТЕХНОЛОГИЧЕСКИХ ПРОЦЕССОВ ПЕРЕРАБОТКИ РАСТИТЕЛЬНОГО СЫРЬЯ

The use of one- and two-stage liquid ring vacuum pumps of a combined type for agricultural processes is justified: drying, extraction, vacuum evaporation and transportation of plant materials. The purpose of the article is formulated, which is to develop a method of theoretical calculation for the selection of liquid ring vacuum pumps of a combined type for the presented agricultural processes. Scientists who have been and are currently continuing research on this problem are presented. The general methodology for calculating the speed of action, adjusted for the flow rate and geometric parameters of a liquid ring vacuum pump (LVN), is described. The technological scheme of the processes of two-stage convective-vacuum-pulse drying (DCVID) and extraction is described and the use of a two-stage liquid-vitrochemical drying agent for them is justified. A method for calculating the speed of action based on the technological parameters of the devices used is presented. A method for determining the speed of action for DKVIS and extraction in the case of using pulsed action on the processed plant material is also described. The rationality of creating pulses during DCVIS in an additional container or one housing (when using a multi-body apparatus) is substantiated. A technological scheme of the process of vacuum transportation of dry bulk plant material is described. It is proposed to use a single-stage liquid liquid pump for this process. A method for selecting a vacuum pump based on the required performance and air flow is described. Based on the presented materials, conclusions and conclusions are drawn.

РАСЧЁТ КОМБИНИРОВАННОЙ КОНСТРУКЦИИ ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА

Liquid ring vacuum pumps are widely used in many areas of the agro-industrial complex, in particular for milking processes, storage of plant materials, their drying and extraction, as well as pneumatic transport. It has been revealed that one of the main disadvantages of liquid ring vacuum pumps - low efficiency (25-50%) is often caused by hydraulic losses during rotation of the liquid ring on a stationary body, as well as inaccurate physical prerequisites in the equations describing the movement of the liquid ring - a two-phase turbulent flow in the working pump cavity. As a consequence, the pump engineering calculation method leads to overestimated performance characteristics at the design stage. In this regard, a combined design of a liquid ring vacuum pump with a rotating casing has been proposed, in which rotation can be transmitted from the impeller blades to the casing blades (in the case of low and medium speed pump size), through involute engagement, or from the casing blades to the impeller blades (in in case of high and especially high speed of action). The basis for calculating the liquid ring is the continuity equation, the stability condition of the liquid ring and the threshold for the occurrence of cavitation phenomena, as well as a coefficient characterizing the drop in speed for turbulent motion in a bladeless space in areas (suction, maximum, compression, discharge). In this case, the mechanism of movement of the liquid ring in the working cavity of the pump is represented by physical processes in the form of the interaction of two power flows: the hydraulic flow of the working fluid and the thermodynamic flow of the gaseous medium. When calculating the main operating parameter of the pump - the actual speed of action - the evaporation of liquid droplets due to changes in the temperature of the liquid ring was taken into account. The forces acting on the rotating wheel and the rotating body of the combined design of a liquid ring vacuum pump are determined analytically.

ВЫБОР ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА ДЛЯ ШАРОВОЙ МЕЛЬНИЦЫ С ВАКУУМНЫМ ОТВОДОМ

The use of powders is of interest in many industries. At the same time, the degree of grinding of materials depends on the intended purpose; in particular, in the production of paints, it is necessary to ensure a certain fineness of grinding of the pigment. The smaller the particles, the higher its hiding power. However, excessively high grinding fineness may reduce the hiding power of the pigment. It is proposed to grind the pigment in a two-section cylindrical-conical ball mill with vacuum removal of particles of a given degree of grinding. The article describes the design of the mill and shows a diagram of the line for vacuum transportation of the crushed pigment. The purpose of the work is to determine the main parameters of the vacuum line of pneumatic transport when grinding solid organic materials using a ball mill with a vacuum outlet. A method for calculating the geometric, kinematic and dynamic parameters of the developed mill and pneumatic transport line is presented. A significant reduction in energy costs for excess grinding is achieved through timely vacuum removal of crushed particles. The vacuum in the system is created and maintained by a liquid ring vacuum pump. Various options for the operation of the developed installation are described: direct grinding; additional grinding and recirculation of additional liquid generated during the operation of the liquid ring vacuum pump, which further reduces energy costs during grinding

Effect of working fluid temperature on energy dissipation characteristics of liquid ring vacuum pump

Liquid ring vacuum (LRV) pump working fluid temperature has a great influence on its energy efficiency. To improve the energy efficiency of the pump, a new model for the energy dissipation of the LRV pump was established based on the relationship between pump suction capacity, the vaporization loss rate of the working fluid and working fluid temperature. Furthermore, the theoretical model was experimentally verified and quantitatively analyzed. The results showed that the useless power increased and suction capacity decreased with increasing working fluid temperature. When the pump shaft speed was 1500r/min and the inlet pressure was 45kpa, the inlet liquid temperature increased from 15 °C to 45 °C, while the proportion of waste work dissipated by temperature rise of the working fluid significantly decreased from 78.8% to 22.1%. On the contrary, the proportion of the working fluid vaporization, the temperature rise of gas, and the convective heat transfer from the pump outer wall increased. The working fluid temperature positively correlated with the inlet fluid temperature and negative correlated with the inlet flow rate. To further reduce the pump operating temperature, it is necessary to increase the flow rate and reduce the inlet temperature.

Study of Liquid Ring Vacuum Pump's Capacity to Reduce Motive Steam Consumption of Gas Removal System in Indonesia's Geothermal Power Plant 117 MW

Study of Liquid Ring Vacuum Pump's Capacity to Reduce Motive Steam Consumption of Gas Removal System in Indonesia's Geothermal Power Plant 117 MW

Designing the technology and composition of plant extracts using reduced atmospheric pressure

The study aims to establish the regimes and parameters of extraction of bioactive substances from raw plant materials by means of extraction with reduced atmospheric pressure for the purpose of manufacturing non-alcoholic functional syrups. The work is performed by leading specialists of the Kemerovo State University using conventional methods. Preparation of the extracts involves aqueous alcoholic treatment of the crushed mass of raw plant materials selected according to the functional parameters. Extraction is performed in a Soxhlet extractor with an advanced liquid ring vacuum pump. The extraction process is monitored by changes in the content of terpenoids in the extract obtained and the mass fraction of dry matter. As a result, the study establishes the parameters and regimes for carrying out and intensifying the extraction of terpenoids and dry matter from fennel, anise, caraway, and dill: pressure – 0.2 MPa, extraction temperature – 50°С, duration of the process – 45 min, solvent – 40 % aqueous alcoholic solution, raw material particle size – 2-3 mm. These process conditions guarantee the highest degree of extraction of terpenoids and dry matter from raw materials, as well as reduce the time and economic costs.

ВАКУУМНЫЕ ТЕХНОЛОГИИ ПРОИЗВОДСТВА ПОРОШКОВ И ЭКСТРАКТОВ ИЗ ОВОЩЕЙ, ПЛОДОВ И ЯГОД ДЛЯ ФУНКЦИОНАЛЬНЫХ ПРОДУКТОВ ПИТАНИЯ

The development of technologies and equipment for obtaining food products with the addition of functional biologically active substances from vegetables, fruits, berries in the form of powders and extracts is promising. The technologies of vegetable processing of raw materials: cleaning, cutting, drying, grinding, extraction are analyzed. The scheme of the technological processing line for the production of plant powders and extracts is given, which provides for the use of production waste as animal feed. It was revealed that the finished product in the form of dried material (chips) can be obtained at the drying stage, and the remaining distillate is collected after extraction. As an example of the results obtained empirically, the drying curve of the cauliflower "Françoise" and the curves of the extraction of strawberries "Moroshko" are considered. Experimental studies of the drying process were carried out on the developed two-stage convective vacuum impulse drying plant, consisting of a convective fluidized bed dryer and a vacuum cabinet. The universal vacuum-pulse extraction-evaporator is designed for the study of extraction. A comparison of different extraction options was carried out: infusion, heating, heating with stirring and extraction using vacuum. It has been established that vacuum extraction gives the highest yield of dry soluble substances. The main element of the described installations is a liquid ring vacuum pump. Depending on the required vacuum value, it can be singlestage or two-stage. Its use provides sparing temperature conditions, excluding the loss of biologically active substances, and also helps to reduce the time spent on processes.

Novel efficient energy saving approach for liquid ring vacuum pump in coal mine gas drainage

Liquid ring vacuum (LRV) pumps used in the coal mine gas drainage system waste a considerable amount of electrical energy due to the extremely low efficiency, which has been a dramatic limitation over many decades not effectively solved using the conventional structural optimization method. Here a novel approach for drastic improvement of LRV pump efficiency, based on turbulent drag reduction theory, is proposed to reduce the useless energy consumption. Furthermore, a new kind of drag-reducing working fluid (DRWF) for the LRV pump and a supporting closed energy-efficiency system, are developed. Industrial-scale measurements are conducted on the LRV pumps with various models to evaluate the influence of the new DRWF on the overall pump performance. The experimental results show that the new approach can achieve approximately 10% pump efficiency improvement and maximally 21–24% energy-saving rate at an optimum concentration of xanthan gum of 4000 ppm in the DRWF. A cost-effectiveness analysis shows the economic viability of this approach. This technology has been commercially applied to reduce the electricity waste in coal mine gas drainage system, and the energy-saving rate reaches 15–22%, and the carbon emissions reduction for Gucheng mine in China can reach 987 tons per year, which is proved to be an effective approach to achieve China's carbon peak and neutrality goals.

Research on hydraulic loss of liquid ring vacuum pump and optimization of shell profile for high efficiency and energy saving

The shell profile of liquid ring vacuum pump has an important influence on the flow channel, the gas-liquid two-phase flow distribution and the working efficiency of liquid ring vacuum pump. Firstly, the hydraulic loss theoretical model of the liquid ring vacuum pump is developed, and the mechanism of hydraulic loss is revealed. Then the scale and distribution of hydraulic loss are studied based on entropy production theory. The results indicate that the direct dissipative entropy production, the turbulent dissipative entropy production and the wall effect entropy production account for 39.85%, 20.24% and 39.91% of total entropy production respectively. Secondly, a high-efficiency and energy saving design method for the shell profile of liquid ring vacuum pump is studied, and the parametric control model for shell profile is proposed based on the direct free form deformation algorithm. The optimized shell profile for maximum suction capacity can achieve the suction capacity increase of 45.7% and isothermal compression efficiency increase of 8.1%, while the optimized shell profile for minimum wall effect entropy production can achieve the wall effect entropy production decrease of 18.7% and specific power decrease of 11.6%. Finally, the multi-objective optimization design is carried out with the elitist nondominated sorting genetic algorithm.

폼산칼륨 수용액 농도에 따른 액봉식 펌프의 진공성능에 관한 실험적 연구

Liquid ring vacuum pumps using water as the liquid ring fluid (LRF) have a definite vacuum degree limiting characteristic according to the vapor pressure of water. As the degree of vacuum increases, the efficiency of the vacuum pump decreases rapidly, and it is difficult to have a lower vacuum pressure. Therefore, in order to solve the above problems, the substitute liquid ring fluid with properties of the low viscosity and low vapor pressure are selected to expand the usable vacuum area and improve energy efficiency. The liquid ring fluid in this study was potassium formate solution (PFS) and water, and the performance test was conducted at various concentrations of 0~70%. As a result, the vacuum performance decreased due to the increase in the internal temperature of the liquid ring vacuum pump for all liquid ring fluids. However, it has a lower vapor pressure than conventional water and the vacuum pressure of the pump is improved. In addition, it was observed that the pump performance improved as the concentration increased.

КАВИТАЦИОННЫЕ РАЗРУШЕНИЯ В ЖИДКОСТНОКОЛЬЦЕВЫХ ВАКУУМНАСОСАХ

The relevance of studying the parameters of operation of liquid ring vacuum pumps and the development of new designs is due to their demand in the agro-industrial complex. The paper provides a description of the cavitation phenomena that occur during the operation of a liquid ring vacuum pump. Cavitation degrades pump performance and can often cause failure. It can occur due to: low barometric pressure; large vacuum suction height; high temperature of the pumped liquid; additional pressure loss in the pump impeller. To identify the possibility of cavitation in a liquid ring vacuum pump, a cavitation characteristic is compiled. It is based on testing the pump at a constant flow rate of the working fluid and the speed of the impeller, performed on a special installation, the scheme of which is presented in the article. Cavitation phenomena in a liquid ring vacuum pump with water occur at a vacuum above 90%. For a single-stage liquid ring vacuum pump, this value corresponds to a vacuum range of 20-10 kPa, for a two-stage one - 10-1 kPa. A photo of the impeller blades of a liquid ring vacuum pump exposed to cavitation is presented. The formula for calculating the cavitation coefficient, which characterizes the cavitation reserve, is given. Its value depends on the design of the considered pump and the operating conditions of its operation and can be determined empirically. Practical recommendations are offered to prevent the occurrence of cavitation phenomena: decrease in water temperature; improving the accuracy of model selection; equipping the pump with an air ejector; use as a working fluid with a low content of saturated steam; production of the impeller from materials with increased anti-cavitation properties

Experimental study on pressure fluctuation characteristics of gas–liquid flow in liquid ring vacuum pump

Experimental study on pressure fluctuation characteristics of gas–liquid flow in liquid ring vacuum pump

A Comprehensive Review of Liquid Ring Vacuum Pumps and Compressors for Improving Global Efficiency and Energy Saving

Liquid ring vacuum pumps and compressors are mechanical positive displacement turbomachines that can operate in the mode of both vacuum compressor and vacuum pump. They are widely used in the fields of filtration, cryogenic, reaction, gas injection, condensation, evaporation, and convective drying. Despite their low performance, they have many advantages such as low costs, simplicity, reliability, improve suction characteristics, and in many cases, can provide a more efficient option. Improving efficiency is the key to decrease energy consumption and costs. The article analyzed and evaluated the previous investigations regarding these machines with a focus on challenges of improving efficiency, advances in numerical simulation, and experiments to afford beneficial insight on future research and next steps. The study revealed that the thermal interaction and the cavitation phenomenon are among the most important problems that require further research.

УПРОЧНЕНИЕ МЕТАЛИЗАЦИЕЙ ПОЛИМЕРНЫХ ДЕТАЛЕЙ МАШИН И МЕХАНИЗМОВ АПК, ПОЛУЧЕННЫХ ПОСРЕДСТВОМ АДДИТИВНЫХ ТЕХНОЛОГИХ

The active introduction of additive technologies in many industries, including agriculture, determines the relevance of studying the properties of materials used in printing and the characteristics of the resulting products. Polymeric materials are widely used in 3D printing, which can be used to create new composites with the required parameters. One of the approaches to significantly improve the properties of parts made of polymers obtained using 3D printing is their metallization. The article proposes a technology for surface hardening of parts made of thermoplastic polymer materials. This technology is based on combining the action of an external heat flux, which is directed to the hardened surface, and a magnetic field, acting from the opposite surface of the part. Under the influence of magnetic and thermal fields, diffusion of metal powder particles into the polymer surface occurs. In particular, the hardening of the impeller blade of a liquid ring vacuum pump made of ABS plastic by means of three-dimensional printing using FDM technology is considered. The characteristics of the used thermoplastic polymer, which affect the regime parameters of the printing process and subsequent hardening, are considered. The developed installation is described, by means of which magnetothermal reinforcement is carried out. The following surface hardening parameters are possible: molding pressure 2 MPa; preheating the mold to 160-180℃ (approximately 20℃ lower than the melting point of ABS plastic); exposure at the specified temperature and pressure for no more than 2 minutes, followed by cooling in air. Nickel powder with a particle size of 40 μm was chosen as a ferromagnet for hardening. In the future, it is possible to conduct research on the introduction of metal powder into the product during the printing process.

АНАЛИЗ РАСЧЁТА ПРИВОДА КОМБИНИРОВАННОЙ КОНСТРУКЦИИ ОДНОСТУПЕНЧАТОГО ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА

The use of vacuum technologies and equipment in the processing of agricultural products can significantly reduce the loss of biologically active substances and functional components in the final product. Liquid ring vacuum pumps (LHVN) are considered in the work. A significant disadvantage of the LHVN is its low efficiency (about 50%), which is due to hydraulic losses due to friction of the liquid against the stationary pump casing and excessive power consumption for compressing the gas phase. A new design of a combined LHVN with a kinematic lock and an adjustable discharge window (LHVN KM) is proposed. The design allows to reduce the power consumption for the friction of the working fluid against the body; in the initial modes of operation - to minimize over compression and overflow of the gas phase from the injection area to the suction area; at limiting operating modes - to ensure the displacement of the gas phase from the working cavity and eliminate the effect of "locking", accompanied by destabilization of the working process. A standard size range of LHVN KM for various technological processes is presented. For LHVN KM of especially high speed of action, it is proposed to carry out the working process by rotating the body with blades through the designed drive. The scheme and methodology for calculating the drive on the basis of GOSTs and known methods for calculating gearing are described. In order to reduce the weight and size parameters of the LHVN KM, it is proposed to manufacture drive and pump parts from polymeric materials with subsequent hardening by a magnetothermal method.

АДДИТИВНЫЕ ТЕХНОЛОГИИ ПРОИЗВОДСТВА ДЕТАЛЕЙ ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА ДЛЯ ПРОЦЕССОВ АПК

. The tasks of prototyping using 3D printing are relevant for the needs of the agro-industrial complex, where constant modernization of existing equipment and the development of new designs that increase productivity are required. The printing of structural elements of a liquid ring vacuum pump, which is used in the processing of agricultural raw materials, is considered. Prototypes of structural elements of a single-stage liquid ring vacuum pump were manufactured on a Flying bear ghost 5 3D printer (Fig. 1) using FDM technology.The most optimal set of printing parameters was determined by the method of layer-by-layer deposition modeling. The selected modes provide the required quality indicators of the liquid ring vacuum pump prototype. The following parameters are considered: layer height, extruder nozzle and desktop temperatures, airflow during printing, speed, infill percentage and the need for supports. The analysis of the influence of each of the parameters on the characteristics of the finished product was carried out. It has been established that in order to obtain these structural elements without serious defects with a minimum consumption of material and the shortest printing time, it is necessary: the height of each layer is 0.2 mm; extruder nozzle temperature 230 ºС; desktop temperature 100ºС; print speed 60 mm/s; the percentage of filling the model is 25%. Also, for the best quality of the prototypes, constant airflow was used and supports were used in places where the model has significant protrusions. The manufactured prototypes allow evaluating the design features of the developed liquid ring vacuum pump and conducting simple tests for its performance in order to further eliminate the identified shortcomings of the prefabricated structure.