Experimental Test Setup for Deoiling Hydrocyclones Using Conventional Pressure Drop Ratio Control

Summary Produced water is a major challenge in the oil and gas industry, especially with the aging of oil fields. Proper treatment of produced water is important in reducing the environmental footprint of oil and gas production. On offshore platforms, hydrocyclones are commonly used for produced-water treatment. However, maintaining the efficiency of hydrocyclones subjected to plant disturbances is a difficult task owing to their compact nature. This paper describes a new experimental test rig built at the Department of Mechanical and Industrial Engineering at the Norwegian University of Science and Technology for testing industrial-scale hydrocyclones. The test setup can emulate first-stage separation and create plant disturbances, such as changes in flow rate, oil concentration, and oil droplet distribution at the inlet of the hydrocyclones. Also, the setup is capable of testing different control algorithms, which helps to maintain the efficiency of hydrocyclones in the presence of such disturbances. The test rig is equipped with various instruments that can monitor such parameters as pressure, flow, temperature, and oil concentration. A typical pressure drop ratio (PDR) control scheme for hydrocyclones is tested in the test rig, which can control the disturbances in the inflow rate. The PDR control scheme does not detect disturbances in the inlet oil concentration and changes in droplet distribution, and these scenarios are shown experimentally in this paper.

DESIGN AND TEST OF SELF-PROPELLED STRADDLE-TYPE LYCIUM BARBARUM L. SPRAYING MACHINE

According to the planting agronomy of Lycium barbarum L. in Ningxia, a self-propelled straddle-type sprayer was designed. The aim was to reduce the labor requirements, improve the spraying effect to the middle and lower parts of the canopy, reduce the influence of natural wind on droplet drift, and recycle excess liquid medicine to reduce environmental pollution. Tests showed that the coverage rate of liquid medicine on the leaf surface and back of the leaf peaked at 84.2% and 48.3%, respectively, when spraying pressure was high. Under different spraying distances, the coverage rate of liquid medicine on leaf surface and back of leaf reached 73.3% and 38.3% at the shortest distance. The uniformity of the spray droplet distribution was good, the use error was less than 10%, and the excess liquid was effectively recovered.

Investigation of Droplet Size Distribution for Vibrating Mesh Atomizer

Vibrating mesh atomizers (VMA) are increasing in demand for various aerosol applications due to their ability to generate uniformly sized droplets. Currently there are two types of VMA (commercial metallic membranes and silicon based). High Uniformity and control of small droplet size are the basic requirements for many aerosol applications, for which ultrasonic or VMA are employed. However, there is limited research on understanding the droplet size distribution of different types of atomizers. In this study three aerosol generators were investigated: Ultrasonic, metallic VMA, and MEMS-based silicon VMA. The primary objective was to compare these devices on droplet size distribution and mechanism of action. A systematic study to compare the performance of the two VMA was investigated based on droplet distribution, volumetric median diameter (VMD) using liquids with different physiochemical properties. Size distribution of the droplet produced by the metallic VMA was twice the span compared to silicon VMA for fluids with viscosity <2cP. The metallic VMA also resulted in an increase in VMD as the viscosity increased, whereas the Si VMA did not see a significant increase in VMD. The silicon-based VMA demonstrated a 4-15x increase in fine particle fraction control compared to metallic VMA. The results demonstrate that silicon based VMA has narrower droplet distribution with more uniform droplet size and lower span compared to metallic VMA.

A Reconfigurable Perovskite/Polymer Composite Film for Real-Time Detection of Agricultural Spraying

Responsive composites that can display sophisticated responses under environmental stimuli are of paramount importance for developing smart materials and systems. However, the hierarchical design of their multiscale constituents to achieve such response remains a challenge. Here, we report a responsive polymer composite obtained by integrating hierarchical interactions between the polymer network meshes, perovskite nanoinclusion, and a microstructured layout. More specific, a layered composite film has been made with perovskite nanoparticles embedded in a hydratable polymer network as the top layer. The perovskites inclusions can undergo a reversible transformation between a nanocrystalline state and a dissociated ion state, triggered by spraying aqueous solutions on the polymer top layer, resulting in an on/off switch of fluorescence at 510 nm. Meanwhile, the surface layer experiences a reconfigurable micro-wrinkling that can gradually change the film transmittance between 90% and 10%. The two orthogonal responses show a good reversibility for at least 15 cycles. They can be manipulated independently as they respond differently to the amount of water applied. We demonstrate the use of such film by real-time, quantitative, and repeatable detection of spraying and subsequent droplet distribution. Such a sensing capability is urgently needed in precision agriculture for fast assessing the deposition quality of pesticides and fertilizers, yet still not available. Our findings enable the design of perovskite-based responsive composites with multiple functions as well as novel device applications in sensors, actuators, and optoelectronics.

An Aerosol Containment and Filtration Tent for Intubation During the COVID-19 Pandemic

Background. Exposure to infectious droplets confers a high risk for infection transmission by the SARS-CoV-2 coronavirus. Aerosolizing procedures pose particular concern for increasing healthcare workers’ (HCWs) risks of infection. Multiple creative personal protective equipment solutions have been utilized to minimize exposure to infectious particles; however, the overall benefit of many of these devices is limited by a number of factors. Methods. We designed an intubation tent consisting of a metal frame and a clear plastic sheet. The flexible walls of our tent offer increased maneuverability & access, although the efficacy in reducing risk of transmission to HCWs remained unclear. Using an atomizer, particle generator, and matchstick smoke, we simulated the generation of infectious respiratory droplets and aerosols and tested whether our device effectively decreased the concentration of these particles to which a provider might be exposed. Finally, we tested whether the addition of a vacuum fan fit with a high efficiency particulate air filter designed to evacuate contaminated air would influence particle concentrations inside and outside the tent. Results. Droplet dispersion tests with the tent in place showed that the simulated droplet distribution was limited to surfaces within the tent. Aerosol testing under a variety of circumstances consistently showed only a minor rise in particle concentration in the air outside the tent despite an initial peak of particle concentration during generation within. All testing demonstrated declining inside concentrations over time. Conclusions. Our simulations suggest our device has the potential to effectively decrease HCWs’ exposure to infectious droplets and aerosolized viral particles.

Preparation and application of a thidiazuron·diuron ultra-low-volume spray suitable for plant protection unmanned aerial vehicles

Spraying of defoliant can promote centralized defoliation of cotton and advance maturity to facilitate harvesting. Modern pesticide application equipment includes plant protection unmanned aerial vehicles (UAVs), which are used widely for spraying defoliants. However, commonly used defoliant formulations are mainly suspension concentrates and water-dispersible granules, which need to be diluted with water when used. These are not suitable for plant protection UAVs with limited load capacity, especially in arid areas such as Xinjiang, China. Therefore, we prepared a thidiazuron·diuron ultra-low-volume (ULV) spray, which can be used directly without dilution in water. We found that ULV sprays had better wettability than the commercially available suspension concentrate, could quickly wet cotton leaves and spread fully. The volatilization rate was lower. ULV sprays also showed better atomization performance and more uniform droplet distribution than the commercially available suspension concentrate. At a dosage of 4.50–9.00 L/ha, the coverage rate on cotton leaves was 0.85–4.15% and droplet deposition densities were 15.63–42.57 pcs/cm2; defoliation rate and spitting rate were also greater than those of the reference product. This study could be contributed to the development of special pesticide formulations suitable for UAVs.

AN ANALYSIS OF THE LIQUID FILMS BREAK-UP USING THE COMPUTER VISION TECHNIQUE

The aim of this paper is to introduce a novel approach for analysing the droplet formation in a transonic flow. The method suggested in this work is based on the combination of the measured data from the wind tunnel by an optical measurement and image processing. A new wind tunnel was developed for the study of the liquid film atomization at high speed flows similar to ones that can be found in steam turbines. The coarse droplets in steam turbines are formed from the liquid films on the blades and inner casings. The coarse droplets formed on the stator blades don´t follow the bulk flow and collide with the following moving blades. These collisions cause erosion and corrosion processes, which have an unfavourable effect on the reliability and the efficiency of the low pressure stages of steam turbines. The tunnel is equipped with a standard instrumentation for the measurement of the flow properties and for the analysis of the size distribution of the droplets. Two measurement methods were used for the measurement of the size of the droplets, photogrammetry and light scattering. In this paper, the image processing of the captured images is discussed. The images were taken by a camera with a telecentric lens. The paper contains an assessment of three image processing methods used for the measurement of the droplet distribution by the light extinction. Moreover, the formation of the droplets is captured on the trailing edge of the profile in the flow. The results bring a new view on the formation of droplets at high speeds.