Suction Position Research Articles

A Dual-Arm Robot That Manipulates Heavy Plates With the Support of a Vacuum Lifter

A vacuum lifter is widely used to hold and pick up large, heavy, and flat objects. Conventionally, when using a vacuum lifter, a human worker watches the state of a running vacuum lifter and adjusts the object&#x2019;s pose to maintain balance. In this work, we propose using a dual-arm robot to replace the human workers and develop planning and control methods for a dual-arm robot to raise a heavy plate with the help of a vacuum lifter. The methods help the robot determine its actions by considering the vacuum lifer&#x2019;s suction position and suction force limits. The essence of the methods is two-fold. First, we build a Manipulation State Graph (MSG) to store the weighted logical relations of various plate contact states and robot/vacuum lifter configurations, and search the graph to plan efficient and low-cost robot manipulation sequences. Second, we develop a velocity-based impedance controller to coordinate the robot and the vacuum lifter when lifting an object. With its help, a robot can follow the vacuum lifter&#x2019;s motion and realize compliant robot-vacuum lifter collaboration. Real-world experiments are carried out to investigate the proposed planning and control methods. The results show that a robot can effectively and flexibly work together with a vacuum lifter to manipulate large and heavy plate-like objects with the methods&#x2019; support. <i>Note to Practitioners</i>&#x2014;This paper is motivated by the vacuum lifters used for transporting heavy plates in a factory that produces building materials. In the factory, a human worker attaches the suction cup of a vacuum lifter to a plate and controls the vacuum lifter to pull the plate up. Meanwhile, another human worker moves and lifts the plate to a goal pose, following the vacuum lifter while maintaining balance. The job is dangerous as the plate is heavy, and the vacuum lifter is not always strong enough to hold the plate firmly. Inspired by the usage and safety problem, we in this paper develop a planning and control method for a dual-arm robot to replace humans. The robot coordinates its motion to work with the vacuum lifter and performs lifting tasks. The vacuum lifter could remain operated by a human worker or be actuated by signals from the dual-arm robot or other third-party machines. The work is complementary to our previous study that developed planners for robots to use pulley blocks. They together provide extensive knowledge for using low-payload collaboratively robots to manipulate heavy plates.

Numerical Investigation on Suction Flow Control Technology for a Blunt Trailing Edge Hydrofoil

The generation of hydro-mechanical resonance is related to the transition of the boundary layer and the development of vortex shedding. The application effect of suction control in hydrodynamics is equally deserving of consideration as an active control technique in aerodynamics. This study examines how suction control affects the flow field of the NACA0009 blunt trailing edge hydrofoil using the γ transition model. Firstly, the accuracy of the numerical method is checked by performing a three-dimensional hydrofoil numerical simulation. Based on this, three-dimensional hydrofoil suction control research is conducted. According to the results, the suction control increases the velocity gradient in the boundary layer and delays the position of transition. The frequency of vortex shedding in the wake region lowers, and the peak value of velocity fluctuation declines. The hydrofoil hydrodynamic performance may be successfully improved with a proper selection of the suction coefficient via research of the suction coefficient and suction position on the flow field around the hydrofoil. The lift/drag ratio goes up as the suction coefficient goes up. The boundary layer displacement thickness and momentum thickness are at their lowest points, and the velocity fluctuation amplitude in the wake region is at its lowest point as the suction coefficient Cμ = 0.003. When the suction slots are at the leading edge, the momentum loss in the boundary layer is minimal and the velocity fluctuation in the wake zone is negligible.

Analysis of biomechanical characterization of the thumb rubbing method.

Thumb rubbing is one of the widely accepted massage techniques, owing to its simple and effective operation. Exploring the biomechanical characteristics of the thumb rubbing method can assist the understanding of the operating characteristics of manipulation, thereby improvising the therapeutic role of manipulation. To study the kinematic and kinetic characteristics of the thumb kneading method from the biomechanical point of view, and to quantitatively analyze the key points of thumb kneading operation. We explored the biomechanical characteristics of the thumb kneading operation by an analysis of the parameters scored by the experts and students using the "thumb kneading data glove and data collection system". (1) Force trajectory: The expert group showed a regular force trajectory compared to the student group, with a stable thumb suction position, small drift and concentrated force. (2) Force value: The average force value of the expert group was concentrated in the range 0.614 ± 0.041kg, while the average force value of the student group was concentrated in the range 0.650 ± 0.146kg and the difference was not statistically significant. (3) Frequency: The frequency of the expert group was mainly concentrated in the range 134.280 ± 39.106 times/min, while that of the student group was 66.04 ± 23.651 times/min, (P< 0.05). (4) Period: The operation cycle during the thumb kneading of the expert and student groups was mainly concentrated in the range of 0.476 ± 0.117s and (0.990 ± 0.259) s, respectively, and the difference was statistically significant (P< 0.05). The present study revealed that the technical operation of the expert group was more stable and standardized than that of the student group. It was found that the force value was inversely proportional to the frequency of the operation. In the "circular rotation" operation of the thumb rubbing method, the force value conversion degree of different parts of the thumb reflected the motion trajectory. Furthermore, the "circular rotation" operation performed by the expert group was better than the student group. The study of the parameters, including the angle of frequency, period and force value can reflect the biomechanical characteristics of thumb rubbing method to a significant extent.

Aerodynamic and aeroacoustic performance assessment of a vertical axis wind turbine by synergistic effect of blowing and suction

The power efficiency of Darrieus wind turbines significantly deteriorates during rotation caused by periodic dynamic stall at low tip speed ratios. This leads to a strong fluctuation in torque and a reduction in energy acquisition. This paper aims to improve the aerodynamic performance of an H-type Darrieus wind turbine using an innovative fluidic flow control technique based on the synergistic effect of blowing and suction. The aeroacoustic noise emissions accomplished with this enhancement are evaluated. The Improved Delayed Detached Eddy Simulation turbulence model and the Ffowcs Williams-Hawkings acoustic analogy method are adopted to simulate the instantaneous flow field and predict the far field noise. Following validation of the numerical approach using wind tunnel experimental data on a static airfoil, an orthogonal experimental design method was used to analyze and optimize the operating factors. The factors include suction position relative to leading-edge (Ls), blowing position relative to trailing-edge (Lb) and jet coefficient (Cμ). The results indicate that Cμ plays crucial role in determining the airfoil performance, while the role of Lb is almost negligible. Furthermore, the impact of optimal combination of these factors was analyzed based on three different control strategies. It is found that appropriate application of the active control solution can eliminate the wind turbine’s negative torque, avoid excessive alternating load on the rotor and improve the energy extraction efficiency. The aeroacoustic noise estimation shows that the active device can reduce the noise emission by moderating pressure fluctuation, stabilizing the flow field and influencing the vortex shedding. Similarly, the proposed active control solution can reduce the wind turbine noise level by up to 6.56 dB by modifying the sound pressure spectra at frequencies between 100 and 1000 Hz.

Numerical investigations on oscillating aspirations controlling separation flows in linear highly loaded compressor cascades

The effect of boundary layer oscillating suction (BLOS) on the vortex structure of high-load linear compressor cascades is studied by a high-fidelity numerical calculation. The oscillation parameters (amplitude and frequency) and suction control parameters (suction position and mass flow) are continuously adjusted. It was found that higher aerodynamic efficiency could be obtained with suitable oscillation parameters and suction control parameters. This is achieved because BLOS not only absorbs the low-energy fluid in the boundary layer but also optimizes the vortex structure in the compressor passage.

Machine Learning Based Developing Flow Control Technique Over Circular Cylinders

Abstract This paper demonstrates the feasibility of blowing and suction for flow control based on the computational fluid dynamics (CFD) simulations at a low Reynolds number flows. The effects of blowing and suction position, and the blowing and suction mass flowrate, and on the flow control are presented in this paper. The optimal conditions for suppressing the wake of the cylinder are investigated by examining the flow separation and the near wake region; analyzing the aerodynamic force (lift and drag) fluctuations using the fast Fourier transform (FFT) to separate the effects of small-scale turbulent structures in the wake region. A method for stochastic analysis using machine learning techniques is proposed. Three different novel machine learning methods were applied to CFD results to predict the variation in drag coefficient due to the vortex shedding. Although, the prediction power of all the methods utilized is in the acceptable accuracy range, the Gaussian process regression (GPR) method is more accurate with an R2(coefficient of determination) &amp;gt; 0.95. The results indicate that by optimizing the blowing and suction parameters like mass flowrate, slot location, and the slot configuration, up to 20% reduction can be achieved in the drag coefficient.

Numerical study on the steady suction active flow control of hydrofoil in the profile of the blended-wing-body underwater glider

The hydrodynamic performance of the blended-wing-body underwater glider can be improved by opening a hole on the surface and applying the steady suction active flow control. In order to explore the influence law and mechanism of the steady suction active flow control on the lift and drag performance of the hydrofoil, which is the profile of the blended-wing-body underwater glider, based on the computational fluid dynamics (CFD) method and SST k-ω turbulence model, the steady suction active flow control of hydrofoil under different conditions is studied, which include three suction factors: suction angle, suction position and suction ratio, as well as three different flow states: no stall, critical stall and over stall. Then the influence mechanism in over stall flow state is further analyzed. The results show that the flow separation state of NACA0015 hydrofoil can be effectively restrained and the flow field distribution around it can be improved by a reasonable steady suction, so as to the lift-drag performance of NACA0015 hydrofoil is improved. The effect of increasing lift and reducing drag of steady suction is best at 90° suction angle and symmetrical about 90° suction angle, and it is better when the steady suction position is closer to the leading edge of the hydrofoil. In addition, with the increase of the suction ratio, the influence of steady suction on the lift coefficient and drag coefficient of hydrofoil is greater.

Pengaruh posisi tindakan suction terhadap perubahan saturasi oksigen pada pasien yang terpasang ventilasi mekanik di Ruang Intensive Care Unit (ICU)

One of the conditions that cause respiratory failure is airway obstruction. Including obstruction of the Endotracheal Tube (ETT). Endotracheal Tube (ETT) that has been installed requires special attention in maintaining the cleanliness of the accumulation of secretions. Therefore, it is necessary to suction mucus (suction) which aims to maintain a patent airway due to accumulation of secretions. The purpose of this study is to analyze the effect of the suction position on changes in oxygen saturation in mechanically ventilated patients. This type of research is a quasi-experimental research design with one group pre-post test design. The sample technique used by the researcher is a total sampling technique with a total sample of 20 respondents. The respondents of this study were patients in the ICU who received suction. The action taken is the provision of a semi-Fowler position and a supine position when suction is performed. The statistical test used is the dependent t test. The average SpO2 before suction in the semi-Fowler position was 97.10 and after that it was 90.50. The average SpO2 before suction in the supine position was 97.75 and after that it was 85.30. The results of the comparison test between before and after the intervention obtained a p value of 0.000 (p value &lt; 0.05). The conclusion of this study is that there is an effect of the semi-Fowler suction position and the supine/supine position on oxygen saturation in patients who are mechanically ventilated.

Exergy analysis and optimization of MED–TVC system with different effect group divisions

Multi-effect distillation-thermal vapor compression (MED–TVC) systems have attracted increasing attention due to their relatively low steam consumption. In this work, comprehensive thermal and exergy analyses of MED and MED–TVC systems were implemented. Besides, a detailed energy utilization diagram (EUD) analysis was conducted to reveal the mechanism of the internal exergy loss. According to the EUD analysis, TVC could solve energy level mismatch and improve energy utilization. However, the system's exergy loss was greatly increased. With the introduction of TVC, the performance ratio (Pr) increased from 10.88 to 14.11, and the energy consumption (Q) decreased from 224.09 kJ/kg-Mp to 181.30 kJ/kg-Mp. In addition, a countercurrent grouping feed was adopted in the system. The influence of the suction position combined with different effect group division methods for the 13-effect MED–TVC system was also investigated. Five different effect group division methods were analyzed in terms of system efficiency, performance ratio, exergy destruction, and energy consumption. The results indicated that a more uniform distribution of effects among the effect groups was beneficial for improving the performance of the MED–TVC system. Furthermore, both the Pr and system exergy efficiency (y) improved with an increase in the suction effect number.

Continuous saliva suction tube to prevent aspiration pneumonia during upper GI endoscopy.

Continuous saliva suction tube to prevent aspiration pneumonia during upper GI endoscopy.

The Suction Control Characteristics of Flow Separation on NACA 23012

The enormous loss of momentum leads to stall and adversely affects the aerodynamic performance of aeroplane wings which may lead to a disaster, more importantly, risking the safety of the aeroplane by putting lives of passengers on it in danger. Therefore, this paper focuses on the enhancement of aerodynamic characteristics of NACA 23012 through the mitigation of flow separation and delay of the stall at higher angles of attack by using suction for Reynolds number (Re) = 3.4 x 106 . Considering the different suction features such as suction width, suction position, and suction coefficient, the separation delay capability of a suction control is studied. Also, the lift to drag ratio and the impact of energy consumption variation during the control technique are used for estimating the control effects. The Reynolds Average Navier-Stokes (RANS) equations are employed together with the Menter’s shear stress turbulent model. The result of this study revealed that the jet position just behind the separation point at 0.2 % of the chord length shows an outstanding control outcome on the separation and stall, thereby increasing the lift. The lift to drag ration increased proportionately when the suction jet coefficient was increased. At suction coefficient Cq = 0.00225, a 92.1% drag reduction and 72.7% lift enhancement is observed. Hence, the stall angle is moved beyond 21.5o from an initial angle of 16° and the more energy was saved at a high angle of attack.

Effect of wind curtain on dust extraction in rock tunnel working face: CFD and field measurement analysis

Dust pollution in fully mechanized working faces of rock tunnels seriously threatens the safe operation and workers’ health. In order to effectively control the dust and improve the working environment in the working face, we simulated the effect of dust suction position, ds and the exhaust air rate, Qs on dust diffusion at the working face by the CFD method. The accuracy and reliability of the numerical simulation were verified by field measurements. It was shown that when ds was 0, 1/4, 1/2, and 3/4, the overall airflow in the tunnel was in a disordered state. The dust, carried by the airflow, was eventually spread to the whole tunnel. When ds was 1, an effective dust control wind curtain with the airflow direction pointing to the working face was achieved under the joint action of exhaust air and pressing air. A uniform flow covering the full section of the tunnel was formed within the range of 4.2–6.5m from the working face. The dust was controlled in an enclosed space between the roadheader and the working face. When Qs was 330–500 m3/min, an effective dust control wind curtain was always formed in front of the roadheader. Consequently, the recommended air exhaust rate under the minimum energy consumption was 330 m3/min.

A combined application of micro-vortex generator and boundary layer suction in a high-load compressor cascade

In the current study, the effects of a combined application between micro-vortex generator and boundary layer suction on the flow characteristics of a high-load compressor cascade are investigated. The micro-vortex generator with a special configuration and the longitudinal suction slot are adopted. The calculated results show that a reverse flow region, which is considered the main reason for occurring stall at 7.9° incidence, grows and collapses rapidly near the leading edge and leads to two critical points occurring on the end-wall with the increasing incidence in the baseline. As the micro-vortex generator is introduced in the baseline cascade, the corner separation is switched to a trailing edge separation by the thrust from the induced vortex. Meanwhile, the occurrence of failure is delayed due to the mixed low energy fluid and main flow. The synergistic effects between the micro-vortex generator and the boundary layer suction on the performance of the cascade are superior to the baseline at all the incidence conditions before the occurrence of failure, and the sudden deterioration of the cascade occurs at 10.3° incidence. The optimal results show that the farther upstream suction position, the lower total pressure loss of the cascade with vortex generator at the near stall condition. Moreover, the induced vortex with a leg can migrate the accumulated low energy fluid backward to delay the occurrence of stall.

Optimization of a Low-Voltage Load Switch for a Smart Meter Based on a Double Response Surface Model

The existing electric energy meter load switches have issues such as a low electrical life, poor resistance to short-circuit currents, high contact point resistivity and severe heating. Research has thus been conducted on the optimization of the electric energy meter built-in load switch mechanism to establish a double response surface model for the electromagnetic attractive force and reed reaction force. The model introduces a niche fitness sorting strategy and a Gaussian mutation mechanism that are based on the standard particle swarm algorithm and form an improved multi-objective particle swarm optimization algorithm in which the static attractive force is regarded as the optimization objective. The multi-objective optimization of the structural parameters of the electromagnetic system and the reed system was carried out, and the optimization results were applied in the devices’ design and implementation. The new structure improves the electromagnetic suction and reed force at the suction position. And the results from simulation show that the proposed method exceeds that of the back propagation neural network method in achieving the optimization goal and the new structure can effectively improve the performance of meter built-in load switch by avoiding the recoil phenomenon.

Energy integration of multiple-effect evaporator, thermo-vapor compressor, and background process

Multiple-effect evaporators are commonly used in various industries such as food process, desalination, pulp and paper, etc. for increasing the liquor concentration. Multiple-effect evaporator is an energy intensive equipment. It is often integrated with various energy saving techniques for minimizing the energy consumption. A common technique is integration of multiple-effect evaporator with thermo-vapor compressor. In thermo-vapor compressor the low-pressure vapor produced in multiple-effect evaporator is compressed with the help of the high-pressure motive steam to produce an intermediate-pressure vapor, which in turn acts as a heat source for the multiple-effect evaporator. The optimal location of vapor suction position for thermo-vapor compressor can significantly affect the energy consumption of integrated multiple-effect evaporator and thermo-vapor compressor system. The other way of reducing the energy consumption is by integrating multiple-effect evaporator with the background process. The present work focuses on the development of a methodology to minimize the overall energy consumption by thermally integrating multiple-effect evaporator, thermo-vapor compressor, and the background process. A theorem for optimal location of vapor suction position for thermo-vapor compressor is proposed. Two examples are considered in this study for demonstrating the proposed methodology. An economic analysis is also carried out for calculating the cost benefit for the overall integration. Overall integration leads to 28% of energy saving and 22% reduction in annual cost for corn glucose example compared to standalone system. Similarly, for desalination example, 44% energy and 20% annual cost savings are observed.

Integration of thermo-vapor compressor with multiple-effect evaporator

Thermo-vapor compressor (TVC) is used for compressing the low-pressure vapor with the help of the high-pressure motive steam, to produce the medium pressure vapor. A substantial portion of energy may be conserved by integrating TVC with the multiple-effect evaporator (MEE). The common practice in desalination industry is to compress the vapor produced in the last effect of a MEE using TVC to reduce the overall motive steam requirement. Such integration does not necessarily guarantee energy optimality. The objective of the present work is to optimally integrate TVC with a MEE system to maximize the gain output ratio (GOR). GOR is defined as the ratio of the mass flow rate of vapor produced in MEE to the mass flow rate of the motive steam supplied to TVC. GOR is the measure of the energy efficiency of MEE system. Using the principles of Pinch Analysis and techniques of mathematical optimization, a new methodology for integration of TVC with MEE is proposed in this paper. This is the first analytical methodology to optimally integrate TVC with MEE, avoiding multiple simulations of the overall system. A Theorem is proposed to directly calculate the optimal location of TVC suction position. The proposed methodology gives the designer the freedom to design an MEE-TVC with minimum energy consumption and without carrying out the detailed simulation of the entire system. The methodology is demonstrated through the illustrative case studies for concentrating corn glucose, and freshwater production through thermal desalination. In the case of corn glucose, the optimal integration of TVC with 2-effect MEE resulted in the increase in GOR by 10.1% with a decrease in the specific area requirement by 4.1%. For a desalination system with 11-effect MEE, the optimal integration of TVC improves the GOR by 1.5% and reduces the specific area by 4.3%. Furthermore, sensitivity analysis is carried out to determine the optimal operating parameters for both case studies.

Optimization of location of thermo-compressor suction in MED-TVC desalination plants

AbstractMulti-effect desalination with thermal vapor compression (MED-TVC) is particularly more attractive than other thermal desalination systems due to its low energy consumption. One of the major component of MED-TVC desalination system is thermo-compressor. The overall efficiency of the system is directly influenced by the performance of thermo-compressor. It enhances system’s efficiency by reducing the energy consumption. The location of the steam extraction has a great effect on the performance of the MED-TVC plants. Higher gained output ratio of the desalination plant can be obtained at the optimum position of vapor extraction in the MED-TVC system. The optimization of location of suction position of thermo-compressor in MED-TVC desalination plants could result in maximization of gain output ratio (GOR) and consequently reduction in energy consumption. Furthermore, increasing the suction pressure also results in decreasing the energy consumption of the system. Therefore, this work will analyze the ...

Mean Velocity Distributions under Flow in the Mainstream of a T Pipe Junction

Experimental studies of mean velocity distributions under flow in the mainstream of a T pipe junction are conducted and the inlet flow keeps a good agreement with the previous research with the Reynolds number about 2.9 × 105 based on the hydraulic diameter and centerline velocity in the main duct inlet. ATSI Constant Temperature Anemometer hot wire system is used to acquire the velocity data in a low speed wind tunnel. The results show that from the suction position, the correlation coefficient and amplitude ratio decrease strongly and recover slowly as the distance far away from the suction. The influence of different inlet velocity in main duct and velocity ratio is analyzed. It could be expected that the correlation coefficient rises again to 1 again, that is to say, the velocity profile would be normal as a typical symmetry at location far enough. The results would be helpful for designing the ventilation and heat transfer equipment used in high speed train.

Numerical Investigation on the Delay of Boundary Layer Separation by Suction for NACA 4412

Transition flow over airfoils at the higher angle of attack shows a lot of unsteady phenomena such as local separation regions, boundary layer transition, turbulence and shock boundary layer interaction. These phenomena are associated with high energy loss and adversely effects the aerodynamic loads in the form of lift loss and drag increase. Controlling the flow through separation delay by suction at different slots, by flaps, by introducing bumps and sophisticated high lifting devices can mitigate the aerodynamic losses. This paper focuses on the delay of boundary layer separation of 2D NACA 4412 by suction using CFD analysis. Picking out the right suction position augments the aerodynamic performance. So a slot with a width of 2% of the chord length is placed at five different locations starting from 48% to 70% of the chord length. The main part of the paper is related to the selection of a suction position and outcome of different suction pressures at a definite slot. Suction with the lower pressure at a definite position moves the separation of boundary layer in the vicinity of trailing edge of the airfoil most. By suing suctionat suction pressure 65kPa on 68% of the chord length of the airfoil with a constant angle 20 with the upper surface of the airfoil, AOA=130and M=0.6, it is possible to move the transition to turbulent flow about 91% of the chord length of the airfoil near the trailing edge where it is found at 43% of the chord length of the airfoil without suction. So the laminar region is extended and the lift increases. Along with this, at low angle of attack, the lift to drag ratio after suction increases about 2.24 times compared to that of without suction.

Numerical Investigation on Aerodynamic Force of Streamlined Box Girder with Uniform Air Suction

In the present study, the flow around a streamlined box girder with uniform air suction has been investigated numerically. Two-dimensional incompressible unsteady Reynolds averaged Navier-Stokes (URANS) equations are solved in conjunction with the SST kω − turbulence model in simulations. Taking the Great Belt Bridge girder as an example, cases of different suction positions on the girder section were discussed. The effect of the suction ratio and the angle of attack (AOA) of wind also were investigated. The result showed that the aerodynamic drag force was influenced by the uniform suction through either upper surface or lower surface of the box girder. The larger the suction ratio was, the more the drag-reducing could be. The suction position and AOA had a comprehensive effect on the drag force. The vortex shedding frequency was also affected by air suction. For the aerodynamic lift force and moment, air suction showed no obvious influence. If necessary, using a combined suction scheme to reduce the aerodynamic drag force or to control the flow wake would be more efficient in engineering design.