Mixer Design Research Articles

Effective Mixer Design an Important Factor In SSCR Systems for Reduction of NOx from Exhaust of Diesel Engines

In recent decades, the environment has been seriously polluted by the hazardous exhaust components of diesel engines. The international community, which is dedicated to preserving the harmony between nature and humanity, has taken this seriously and imposed strict regulations on Diesel engine manufacturers regarding the quantity of exhaust components from Diesel engines that may apply to the standards of EURO-VI. The SCR technology attempted to reduce the problem somewhat, but the associated problems of solid particle formation on the pipe walls, ammonia slip, and incomplete NOx reduction led to the development of new technology - solid selective catalytic reduction. The use of solid ammonium salt for ammonia generation has shown better results in NOx reduction and reduction of solid particle formation compared to SCR. However, it was not possible to fully resolve the ammonia slip issue. A uniform flow rate of ammonia through the SCR catalyst can reduce NOx efficiently. In this paper, the role of mixer design in achieving a uniform flow rate of ammonia is investigated in detail. The results show that an optimized mixer design leads to efficient reduction of NOx and thus reduces ammonia slip to a great extent. When the mixer is placed near the ammonia injection point, the most homogeneous ammonia distribution is achieved for flow through the SCR catalyst.

The relevance of the use of low-volume rotary disk mixers

In the presented work, a description of the principle of operation of a rotary-disk mixer is given. The author notes that in industry the designs of a rotary-disk mixer with smooth disks having additional elements rigidly fixed in the form of blades or teeth of various shapes are most widely used in industry. The description of 4 developed constructions of working disks with structural differences is given. An experimental proof of the effectiveness of the use of additional working bodies is given. It is noted that the latter lead to the emergence of new highly turbulent flows of the processed medium, which has a positive effect on the processes of emulsification and dispersion. It is shown that with an increase in the proportion of the dispersed phase in a stirred medium, the average size of the droplets of the dispersed phase increases. This is explained by an increase in the concentration of the dispersed phase and the frequency of collisions of droplets of dispersed particles, which lead to coalescence. It has been established that the size of the particles of the dispersed phase decreases inversely with the rotor speed and the increase in the dissipation energy.

DESIGN AND CONSTRUCTION OF MIXER WITH VARIABLE SPEED FOR MANUFACTURING NANOPARTICLE COMPOSITE MATERIALS

Variable speed mixer machine is a tool to help stir and mix resin with nanoparticles, design and build of the mixer plan the design of the variable speed mixer which aims to make the resin viscosity more evenly distributed in the manufacture of composites and determine the performance of the equipment produced by the variable speed mixer. This is because in manual mixing the mixed materials such as resin nanoparticles have not been mixed evenly or homogeneously. This mixer design tool can be used as a basis for developing work in the field of composite mixing, problems in composite manufacturing include; resin flow control and how to prevent the occurrence of white spots (white dots in the composite). y designing and using this variable speed mixer machine, the results of designing a mixer image with variable speed control using solid works software is the first step in working on a mixer design with variable speed control, after having data in the form of design drawings, a product design in the form of a mixer with variable speed is obtained. . speed control. It is known that the specifications of the mixer with variable speed for composites and nanoparticles are known, it is known that the working principle of a mixer with variable speed control for composites and nanoparticles can make the viscosity mixed more evenly. because the stirring speed regulated by the speed control has a constant speed. The results of testing the mixer machine with speed control, namely the motor can work according to the design plan, where the motor can produce rotation with the required variations and can be adjusted as needed.

Improvement in Injection Molding Quality Performance with Innovative Cyclone Mixers Used in Polypropylene with Spherical Silicon Dioxide Composites.

This research proposes an innovative design of a new cyclone mixer for the quality of polymer materials, and it presents a systematic optimization model of process parameters for plastic injection molding. Thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to determine the appropriate thermal properties of processing in order to select appropriate control factors and level values for a Taguchi orthogonal array. The injection molding machine was used to make sample test pieces for tensile strength, hardness and impact strength. Significant factors were found by the signal-to-noise (S/N) ratio with an analysis of variation (ANOVA), and the single-quality optimal parameter combination was obtained. The reproducibility of the experiment was evaluated, and various quality weights were evaluated by principal components analysis (PCA). The multi-quality optimal parameter combination was found, and the comprehensive scores were compared. Finally, the process capability indices were combined with a multi-process capability analysis chart (MPCAC) to compare the process yields of cyclone mixing and screw mixing. The mechanical properties of products were evaluated to verify the performance of cyclone mixing and to provide perfect information for the injection molding quality performance of cyclone mixing and screw mixing. It was concluded that the overall quality of the cyclone mixing products is 42.72, and the total quality of the screw mixing products is 41.85. The total number of defects for the cyclone mixing is 9659 ppm, and that of the screw mixing is 10688 ppm. It can be seen that, for the overall product quality performance, cyclone mixing can be applied in the plastic injection molding process instead of screw mixing.

3D active mixing of confined power law aqueous polymer solutions: a comparative numerical study

PurposeThis paper aims to study the influence that the second invariant of the rate-of-strain tensor of a power law polymeric fluid (aqueous solution of hydroxyethyl cellulose [HEC]) has on convective mixing performance downstream of a 3D confined oscillating prism. Newtonian and non-Newtonian Reynolds numbers, the mass concentration of HEC and prism oscillation frequency were varied.Design/methodology/approachA conceptual problem was designed. Its objective was to analyze the convective mixing of two adjacent flow streams when they pass around a moving confined prism. The rectangular prism had a square section, and its sinusoidal motion was prescribed inside a channel with a square section too. OpenFOAM libraries were used to simulate the flow field. Regarding prism motion, the icoDyMFoam solver was used. The problem was analyzed both at the global level (mixing parameter) and local level (detailed flow topology).FindingsFor constant Reynolds number, increasing mass concentrations of HEC (in the range from 0.2% to 0.5%) led to better mixing parameters. The improvement was linked to the effect that the second invariant of the rate-of-strain tensor had on flow topology. It was found that mixing is maximum when the prism motion and its wake (the frequency of the first instability) are synchronized. In practical terms, this means that the optimum stirring frequency does not need to be very high; it suffices that it ensures that synchronization occurs. The dominant vorticity shedding pattern found was the so-called 2P mode. However, a significant difference was found when compared to the free-stream situation. While in the former, the two vorticity regions that make up the 2P pair come from the prism, in the present confined case, one came from the prism, and the other came from the wall. Another difference was that in the present case, the 2P pairs were much more elongated than in the free stream case, and this had a significant influence on the stretching and bending of streak lines and, therefore, on mixing.Practical implicationsThe study that has been presented has a practical industrial implication for the processes industry because it provides guidelines to design active mixers that deal with aqueous power law polymeric solutions. In parallel, it opens up some new research lines in the direction of studying whether the mixing concept might be modified so as to develop a fully passive system that could be far simpler and, possibly, more attractive to industry.Originality/valueThe originality and value of the study are associated to the systematic approach that has been followed. It has allowed to establish a clear pattern regarding the active mixing behavior of HEC solutions in confined flows. To the best of authors’ knowledge, this could be the first study of this type in the literature. Also, the study has contributed to understand the vorticity shedding patterns that appear in these types of problems and how they shape wake topology and, consequently, mixing performance. The finding that optimum mixing requires synchronization of stirring motion frequency and wake first natural frequency of instability may help to improve the design and operation of industrial mixers dealing with polymeric aqueous solutions.

Comparing the performance of 850 GHz integrated bias-tee superconductor-insulator-superconductor (SIS) mixers with single- and parallel-junction tuner

We present and compare the design and performance of two 850 GHz radial probe fed superconductor-insulator-superconductor mixers, where the antenna is aligned perpendicular to the E-Plane of the input full-height rectangular waveguide connected to a multiple flare-angles smooth-walled horn. Both designs are comprised of 0.5 µm2 hybrid niobium/aluminium-nitride/niobium-nitride tunnel junction, fabricated on top of a niobium titanium nitride ground plane with an Al wiring layer. The entire superconducting circuit is supported with a 40 µm thick quartz substrate. The major difference between the two designs is the method used to cancel out the parasitic junction capacitance for broadband performance. The first design utilises two identical junctions connected in parallel with a short transmission line to convert the capacitance of one junction into the equivalent inductance of the other junction, commonly known as the twin-junction tuning scheme; whilst the second design employs an end-loaded scheme with only one tunnel junction. We found that both methods offer similar radio frequency performances, with close to 2× the double sideband quantum noise temperature, but the twin-junction design is more resilient to fabrication tolerances. However, the end-loaded design offers a much better intermediate frequency (IF) bandwidth performance, made possible by the sub-micron and high current density tunnel junction technology. The improved IF performance is important for many millimetre (mm) and sub-mm observatories, such as future upgrades of Atacama Large Millimetre/sub-mm Array receivers, as well as forthcoming space-borne far-infrared missions. Therefore, we conclude that the single-junction mixer design is the preferred option for THz applications, as long as the fabrication error can be minimised within a certain limit.

A maddock mixer design that mitigates gels in polyethylene resin film applications

Maddock mixers are ubiquitous in plastics processing for single-screw extruders and injection molding plasticators due to their low cost to build and their ability to provide a uniform level of dispersive mixing. If the mixer is designed properly, all entering solid polymer fragments and certain types of gels can be trapped and dispersed into the matrix resin. Many mixers that are used commercially, however, provide lower levels of dispersive stress mixing than required by the process and they can degrade polyethylene (PE) resins. This paper will describe the mechanisms that are occurring in a Maddock mixer and develop guidelines for obtaining optimal mixing stresses while mitigating resin degradation.

High shear mixer works as a heat exchanger enhancing the liquid–liquid direct contact heat transfer

As an indispensable unit equipment in industrial production, the design of efficient heat exchangers is of great significance to improve energy utilization rate. In this paper, the in-line high shear mixer (HSM) was investigated as a heat exchanger for the first time by experiments and assisted with CFD simulations, and the heat transfer performance was measured using kerosene and thermal water as the heat transfer fluids. Effects of operational parameters, including rotor speed, fluids temperature and flow rate, as well as the structural parameters, involving the rotor teeth number, teeth height, and the shear gap, were studied on the volume heat transfer coefficient and the heat transfer efficiency of such inline HSM. The results indicated that the volume heat transfer coefficient can be significantly improved by increasing the rotor speed and the flow rate of the heat transfer fluids, but reducing the heat transfer temperature difference, whereas increasing the thermal fluid flow rate deteriorates heat transfer efficiency. Furthermore, the structural parameters including rotor teeth number and teeth height, the shear gap within the stator and rotor were optimized to enhance the heat transfer of HSM. The optimal HSM possesses a shear gap of 0.5 mm, a teeth height of 10 mm and a teeth number of 6, which can generate larger turbulent energy dissipation rate and higher shear rate, meanwhile make more fluids jet out of the shear gap and stator hole. The maximum volume heat transfer coefficient and heat transfer efficiency can be up to 2522.8 kW·m−3·°C−1 and 92.4% with the optimal structure. Finally, the dimensionless correlations of heat transfer performance were established to guide the operating mode and structural design of high-efficiency high shear mixer.

An in-tire-pressure monitoring SoC using FBAR resonator-based ZigBee transceiver and deep learning models

In automobiles, tires play an important role in ensuring safe driving. Hence tire pressure monitoring system (TPMS) has become the most important safety system in automobile vehicles. In this work, a new indirect TMPS is proposed that measures the pressure of all the tyres indirectly using the available sensors already mounted for typical vehicle dynamics control purposes. The available sensors in vehicles usually contain a power supply module, a microcontroller, and transceiver and resonator circuitry. The available wheel speed sensor is modified by reducing the wireless receiver system in communication protocols to minimize the power consumption. The transceiver structure is modified using a suitable local oscillator (LO) frequency plan based on a temperature-compensated thin film bulk acoustic wave resonator (FBAR). In addition, the proposed TPMS SoC uses a deep-stacked autoencoder to detect the adherence conditions of the tires and a pressure loss based on wheel speed. This module will initially pre-process the speed signals to remove the speed error caused by manufacturing error. After pre-processing, different features such as statistical, frequency-domain and the fitted frequency-domain characteristics are extracted from the wheel speed signal and fed to the learning model for the judgment of the tire state. The proposed system was designed in Verilog synthesis and layout were made in cadence tool. For ASIC implementation, we use TSMC 65 nm CMOS Library for LNA/hybrid mixer design. The performance measures of the pressure detection model in terms of accuracy and errors are evaluated. Also, the performance metrics of the transceiver architecture in terms of gain, NF, IIP3, S11 and FOM are evaluated. The experimental evaluation describes that the model procures a maximum gain of 58 dB, NF of 2.15 dB and IIP3 of 6.6 dBm respectively. The die area is 0.45 mm2with 0.8 supply voltage and 0.83 mW power. In addition to this, the relationship between peak amplitude and speed vehicle regarding time and frequency domain features are evaluated.

High-linearity Gilbert-cell mixer design for cryogenic applications

High-linearity Gilbert-cell mixer design for cryogenic applications

High throughput millifluidics mixer with double triangle baffle for improvement of mixing performance and reduction of flow resistance designed by grey relational analysis

To improve the mixing performance and reduce flow resistance, in this study, a novel mixer with double triangle baffles was designed and optimized by the combination of CFD simulation and grey relation analysis method. Mixing index and Poiseuille number were selected as two key indexes to evaluate the mixing performance and flow resistance of the mixer. The orthogonal experiment was conducted with selecting the aspect ratio of baffles (α), the thickness of baffles (h), the spacing between adjacent baffles (c) and the number of baffles (d) as design variables. Among all design variables, d has the greatest influence on the mixer performances. The results show that the optimized mixer has a maximum increase of 14.25% in mixing index and a maximum decrease in Poiseuille number of 60.02%. Finally, the optimal configuration was scaled-up to centimeter level, which makes the mixer have high mixing performance, low flow resistance and high throughput at the same time. All the findings provide useful references for high throughput mixer design and optimization.

Effect of static mixer on fiber orientation of injection molded fiber‐reinforced composites

AbstractThe effect of an in‐mold static mixer on orientation of fiber‐reinforced polypropylene (PP) was explored within the injection molding process. Several mold geometries and helical mixer designs were assessed via simulation to identify the mixing ability and the potential effect on fiber orientation. It was found that the static mixers within the runner segment could successfully mix the polymer and randomize the fibers but that the fiber alignment reduction was quickly recovered. Injection molding experiments were carried out to verify these simulations using one geometry case. Fiber orientation at different mold locations were measured using micro‐CT (μCT) scans and the degree of fiber orientation was quantified by “goodness of fit” to a normal Gaussian function approach. The experimental fiber orientation results showed good agreement with the simulations. These experiments indicated that the use of a static mixer within the runner system of a mold could be used for mixing the polymer melt after the plasticizing unit of the injection molding machine. However, its effect on changing the overall alignment of the fibers within injection molded parts could be offset by the melt flow downstream of the static mixer, suggesting the importance of mixer location with respect to the part cavity.

Design and parametric optimization of a fan-notched baffle structure mixer for enhancement of liquid-liquid two-phase chemical process

Abstract The mixing uniformity plays a crucial role in a liquid-liquid two-phase chemical process. To quantify the uniformity of the liquid–liquid process, the specific surface area ratio is proposed and studied through computational fluid dynamics simulation. There is a scale effect in the liquid–liquid two phase chemical processing that the specific surface area ratio decreases to 7.01% when the diameter of the Y-like mixer increases from 1 mm to 10 mm. A millimeter-scale mixer with a fan-notched baffle structure was designed, and the baffle unit length, baffle tilt angle, baffle notch size and baffle thickness of the mixer were optimized. Compared with the 1 mm Y-like mixer, the specific surface area ratio of the 10 mm mixer with notched baffle structures increases to 2.5 times and the treatment capacity increases to 100 times. Additionally, experiment and simulation results prove that FNBS is considered to be a suitable structure for enhancing liquid-liquid two-phase. This study will provide a useful reference for the design of large-scale mixers applicable to liquid-liquid heterogeneous chemical processes.

Microfluidic formulation of lipid/polymer hybrid nanoparticles for plasmid DNA (pDNA) delivery

Lipid/polymer hybrid nanoparticles loaded with red fluorescent protein (RFP) encoded plasmid DNA (pDNA) was formulated using poly-lactic-co-glycolic acid (PLGA), cationic lipid DC-cholesterol and surfactant mPEG2000- DSPE. A lipid/ polymer ratio of 1: 10 at 1 mg/mL surfactant concentration was found to be optimal for producing nanoparticles with diameters of 100–120 nm that remained stable upon ultracentrifugation. The production of lipid/ polymer hybrid nanoparticles was investigated using microfluidics with a toroidal mixer design. Our results showed that the flow parameters significantly influenced the physicochemical characteristics of nanoparticles and loading of pDNA was only achieved at flow rate ratio (FRR) of 3: 1. The pDNA associated with nanoparticles was demonstrated to be structurally intact using gel electrophoresis, and the encapsulation efficiency (EE) was measured to be ∼65%. The prepared hybrid nanoparticles resulted in 20% of transfection efficacy in human embryonic kidney cells (HEK293T). This study demonstrated the potential of microfluidics in the development of hybrid nanoparticles for pDNA delivery, thus facilitating the clinical translation of DNA therapeutics.

Effects of Structured 3D Electrodes on the Performance of Redox Flow Batteries

AbstractIn recent years, the interest in redox flow batteries as stationary energy storage devices is growing, for which disordered three‐dimensional electrodes such as felts have been the state‐of‐the‐art due to their large surface area and improved mass transfer properties. However, such electrodes present a high pressure drop and operating cost. In this work, the performance of structured three‐dimensional electrodes in a redox flow battery was studied. Compared to the carbon felt electrode similar electrochemical behaviour was demonstrated with these structured electrodes, which were based on the most common static mixer designs, but at a power consumption that was two to three orders of magnitude lower. Moreover, due to its ordered electrode design unwanted side reactions were suppressed. Consequently, these results demonstrate the influence of structured static mixer based three‐dimensional electrodes in redox flow batteries and the opportunities they hold to surpass the current state‐of‐the‐art.

ОБЗОР И АНАЛИЗ КОНСТРУКЦИЙ СМЕСИТЕЛЬНЫХ УСТРОЙСТВ

The search for a rational design of an animal feed mixer is reduced to determining the structural and operational parameters of a machine that, in terms of its quality and energy costs, would most fully meet the zootechnical and technical and economic requirements. The analysis of the most typical designs of feed mixers was made. Their main shortcomings were revealed: low productivity, complexity of hardware solutions of the main processes, high energy consumption of the mixing unit and the probability of jamming when objects hit the sides; lack of control over the mixing parameters; complexity of the process of unloading the finished product and its automation; manual control of nodes. The classification of feed mixers is proposed according to the indicators of the greatest influence on the quality of the mixture and the energy consumption of the process: the type of feed; kinematic mode; the nature of mixing; the constructive sign; the design of the hopper; the number of mixing shafts; the location of the working body; the method of mixing; by the type of movement of the components being mixed; by the type of working body. A promising design was chosen: according to the type of feed – for dry; according to the kinematic mode - slow–speed; by the nature of mixing – periodic action; by the structural feature - with a fixed body; by the design of the hopper – round shape; by the number of mixing shafts – two–shaft; by the location of the working body – inclined; by the method of mixing – forced action; by the type of movement of the components being mixed - circulating; by the type of working body – screw with an active reverse channel. The use of such a design will ensure high quality of mixing; will increase the technological reliability of the mixing units; it will reduce the specific energy costs for the process of preparing a portion of the lump mixture.

Redesign of water-diesel emulsion fuel mixer

Emissions and fuel consumption are essential parameters to indicate the working of a combustion engine. This paper discusses the methods to achieve lower emissions and efficient fuel consumption. One of the methods is by making emulsion fuel. The emulsion-making methods are surfactant emulsion, micro-emulsion, ultrasonic emulsion, and real-time emulsion non-surfactant (RTES). In the research, the emulsion fuel is a mixture of B30 Biodiesel and water without surfactant that is supplied in real-time after being mixed in a mixer. The ratio is 85% biodiesel and 15% water. The RTES mixer in the old model has a big size, and high-power consumption of about 150-433,5 W. This research's purpose is to develop a simple design and low power consumption of the RTES Mixer. The new RTES mixer design only needs 150 W motor power. Its dimension is more superficial and produces tiny droplets with a main diameter range between 0.1 to 0.5 ?m, with good-mixed visually.

A Cryo-CMOS Wideband Quadrature Receiver With Frequency Synthesizer for Scalable Multiplexed Readout of Silicon Spin Qubits

In this article, a cryo-CMOS receiver integrated with a frequency synthesizer for scalable multiplexed readout of qubits is presented, focusing on radio frequency (RF) reflectometry readout of silicon-based semiconductor spin qubits/quantum dots. The proposed spin qubit readout chip consists of a wideband low noise amplifier (LNA), a quadrature mixer, a complex filter, a pair of in-phase/quadrature (I/Q) intermediate frequency (IF) amplifier chains, and a type-II charge-pump phase-locked loop (PLL) with a programmable frequency divider providing local oscillator (LO) signals. Noise optimizations are applied to the LNA design and the quadrature active mixer design to obtain the required performance. A mode-switching complementary voltage-controlled oscillator (VCO) is proposed to achieve low-power and low-phase noise in a wide-frequency tuning range (46.5%). Circuit modifications and design considerations for robust cryogenic temperature operation are presented and discussed. Measurements show that the receiver provides an average gain of 65 dB, a minimum noise figure of 0.5 dB, an IF bandwidth of 0.1–1.5 GHz, and an image rejection ratio of 23 dB at 3.5 K with a power consumption of 108 mW. This cryo-CMOS receiver with frequency synthesizer for spin qubit readout is a first step toward fully-integrated qubit readout and control.

Design and optimization of a novel ellipsoidal baffle mixer with high mixing efficiency and low pressure drop

AbstractBACKGROUNDThroughput, mixing efficiency and pressure drop are three key performance indicators of a mixer or reactor. However, it is difficult to simultaneously achieve high throughput, high mixing efficiency and low pressure drop in a traditional mixer.RESULTSA novel mixer was designed and constructed by adding an ellipsoidal baffle to a large‐scale Y‐shaped mixer (YEBM) through computational fluid dynamics. The effects of ellipsoid period length, short and long axes, rotation direction, rotation angle and entrance angle of the mixer on mixing and flow characteristics were investigated and optimized. Compared with a 1 mm mixer, the throughput of the optimized YEBM is increased 100 times, the mixing efficiency is comparable and the pressure drop is reduced by 7.4%. Additionally, the application range of the YEBM with high mixing efficiency is extended to 499.1 < Re < 999.8.CONCLUSIONSThe results showed that the novel ellipsoidal baffle mixer could effectively enhance performance and reduce the pressure drop on the premise of ensuring high throughput. All the findings reported provide useful references for enhancement of mixing efficiency and reduction of pressure drop in a large‐scale mixer. © 2022 Society of Chemical Industry (SCI).

Numerical evaluation of an additively manufactured uniform fractal flow mixer

The uniform distribution and mixing of fluids is a common functional requirement in a range of process intensified fluid handling applications. Traditional manufacturing processes have limited the design and performance of flow distributors and mixers. However, the maturing of additive manufacturing (AM) has increased the range of manufacturable geometries, enabling the construction of novel high-performance flow distribution devices. An additively manufactured fractal flow mixer was designed using the concept of self-similar bifurcating channels that symmetrically bifurcates a flow into multiple channels, achieving flow uniformity through a series of sequential stages. After four stages of bifurcation, a y-junction on each channel was introduced before the outlet, mixing the flow from two modules. Computational fluid dynamics (CFD) simulations were carried out to characterise the hydrodynamics and mixing performance of the newly designed mixer over a range of operating conditions and for mixing two gases. Effect of inlet Reynolds numbers (Re) and flow ratio was studied, the maximum relative standard deviation (RSD) was found to be ∼8%, and majority of the flow was uniformly mixed with a distribution index close to unity. The fractal flow mixer was successfully manufactured using vat photopolymerisation (VP) and laser powder bed fusion (L-PBF) techniques without any supports.