Operational performance analysis of spiral capsule robot in multiphase fluid

Robotica ◽  
2018 ◽  
Vol 37 (2) ◽  
pp. 213-232
Author(s):  
Liang Liang ◽  
Bai Chen ◽  
Yong Tang ◽  
Yan Xu ◽  
Yu Liu
Keyword(s):  
Performance Indicators ◽  
Thrust Force ◽  
Optimization Method ◽  
Solid Particles ◽  
Operational Performance ◽  
Maximum Pressure ◽  
High Concentration ◽  
Two Phase ◽  
Axial Thrust ◽  
Mixed Fluid

SUMMARYMinimally invasive surgery is a developing direction of modern medicine. With the successful development of controllable capsule endoscopies, capsule robots are very popular in the field of gastrointestinal medicine. At present, the study of intestinal robots is aimed at the pipeline environment of a single-phase liquid flow. But there exist food residues (i.e. solid particles) or liquid foods in the actual intestine, so intestinal fluid should be liquid–solid or liquid–liquid two-phase mixed fluid. For inner spiral capsule robots with different internal diameters and outer spiral capsule robots, using computational fluid dynamics (CFD) method, the operational performance indicators (i.e. axial thrust force, circumferential resisting moment and maximum pressure to pipeline wall) of spiral capsule robots are numerically calculated in the liquid–solid or liquid–liquid two-phase mixed fluid. By the orthogonal experimental optimization method, the optimum design of spiral capsule robots is obtained in the liquid–solid mixed fluid. The experimental verification has been also carried out. The results show that in the liquid–solid two-phase fluid, the axial thrust force and circumferential resisting moment of the spiral capsule robots decrease with the increase of the size or concentration of solid particles. In the same liquid–solid or liquid–liquid mixed fluid, the operational performance indicators of outer spiral robots are much higher than those of inner spiral robots, and the operational performance indicators of inner spiral robots with bigger internal diameters are higher than those with smaller internal diameters. Adding solid particles of high concentration in the pipeline containing liquid will reduce the drive performance of spiral capsule robots, but adding another liquid of high viscosity will improve the drive performance of spiral capsule robots.

Film Elasticity and Film Stabilization in Firefighting Foam Stabilized by Solid Particles

2017 ◽  
Vol 744 ◽  
pp. 346-349
Author(s):  
Xiu Juan Li ◽  
Rui Song Guo ◽  
Min Zhao
Keyword(s):  
Life Time ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Solid Particles ◽  
High Concentration ◽  
Hydration Effect ◽  
Fixed Area ◽  
The Stability ◽  
Hydration Layers ◽  
Hydration Forces

The structure of the thin liquid films determines the stability of foams and emulsions. In this work the bubbles stretched length with different hollow SiO2 particles concentration is measured when the foam has been stilled for different time. The results show that the bubbles stretched length is longer than that of bubbles when the foam is free of hollow SiO2 particles even when the foam has been stilled for 500mins. The bubbles stretched length increases with increasing the concentration of hollow SiO2 particles. A strong hydration effect leaves a large volume of hydration layers on the solid particles surfaces in aqueous solutions. The water in hydration layers can help the film keep a certain thickness. The existence of hydration forces leads that two particles cannot be too close each other. The high concentration surfactant limited in the fixed area helps the film keep good elasticity. Therefore the film has a long life time with compatible thickness and elasticity and the three-phrase foam is upper stable.

Experimental Determination of Statistical Properties of Two-Phase Turbulent Motion

1960 ◽  
Vol 82 (3) ◽  
pp. 609-621 ◽  
Author(s):  
S. L. Soo ◽  
H. K. Ihrig ◽  
A. F. El Kouh
Keyword(s):  
Gas Phase ◽  
Tracer Diffusion ◽  
Statistical Properties ◽  
Solid Particles ◽  
Turbulent Motion ◽  
Two Phase ◽  
Gaseous State ◽  
Diffusion Technique ◽  
And Diffusion

Experimental methods for the determination of certain statistical properties of turbulent conveyance and diffusion of solid particles in a gaseous state are presented. Methods include a tracer-diffusion technique for the determination of gas-phase turbulent motion and a photo-optical technique for the determination of motion of solid particles. Results are discussed and compared with previous analytical results.

Harmonic Synthesis Design Methodology for Dynamic Spring Balancing

1996 ◽  
Vol 118 (4) ◽  
pp. 733-740 ◽  
Author(s):  
Eungsoo Shin ◽  
D. A. Streit
Keyword(s):  
Dynamic System ◽  
Initial Conditions ◽  
Phase 1 ◽  
System Optimization ◽  
Optimization Method ◽  
Optimization Techniques ◽  
System Response ◽  
Two Phase ◽  
Walking Machine ◽  
Synthesis Design

A new spring balancing technique, called a two-phase optimization method, is presented. Phase 1 uses harmonic synthesis to provide a system configuration which achieves an approximation to a desired dynamic system response. Phase 2 uses results of harmonic synthesis as initial conditions for dynamic system optimization. Optimization techniques compensate for nonlinearities in machine dynamics. Example applications to robot manipulators and to walking machine legs are presented and discussed.

scholarly journals Two-Phase Dusty Fluid Flow Along a Rotating Axisymmetric Round-Nosed Body

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Boundary Layer ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Solid Particles ◽  
Dust Particles ◽  
Computational Domain ◽  
Two Phase ◽  
Carrier Fluid ◽  
Boundary Layer Equations ◽  
Implicit Finite Difference

This article is concerned with the class of solutions of gas boundary layer containing uniform, spherical solid particles over the surface of rotating axisymmetric round-nosed body. By using the method of transformed coordinates, the boundary layer equations for two-phase flow are mapped into a regular and stationary computational domain and then solved numerically by using implicit finite difference method. In this study, a rotating hemisphere is used as a particular example to elucidate the heat transfer mechanism near the surface of round-nosed bodies. We will investigate whether the presence of dust particles in carrier fluid disturbs the flow characteristics associated with rotating hemisphere or not. A comprehensive parametric analysis is presented to show the influence of the particle loading, the buoyancy ratio parameter, and the surface of rotating hemisphere on the numerical findings. In the absence of dust particles, the results are graphically compared with existing data in the open literature, and an excellent agreement has been found. It is noted that the concentration of dust particles’ parameter, Dρ, strongly influences the heat transport rate near the leading edge.

Initial Investigation Into Helical Milling of Laminated Stacks of Electrical Steel

2012 ◽  
Author(s):  
Howard Liles ◽  
J. Rhett Mayor
Keyword(s):  
Electrical Steel ◽  
Thrust Force ◽  
Initial Study ◽  
Helical Milling ◽  
Burr Formation ◽  
Spring Back ◽  
Plunge Milling ◽  
Axial Thrust ◽  
Electrical Steels ◽  
Thrust Forces

This paper serves to report the findings of an initial study on the holing of laminated stacks of electrical steels. Three different holing methods were considered: plunge milling, helical milling (orbit milling), and drilling. Stack delamination, axial thrust force, and burr formation were measured at various feed rates for each process and utilized as comparison metrics. Results from the initial experimental investigation indicate that drilling produces significant burr and plunge milling, whilst reducing burr formation compared to drilling, led to delamination of the stack. Helical milling minimized thrust forces, avoided delamination and minimized burr formation. An interesting spring back effect was also observed during the cutting of the laminated stacks. It is concluded that helical milling is a viable and effective processing method for making holes in laminated stack of hard electrical steels.

scholarly journals The influence of supplier integration and lean practices adoption on operational performance

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Graziela dos Santos Bento ◽  
Klaus Siegmar Schuldt ◽  
Luciano Castro de Carvalho
Keyword(s):  
Survey Data ◽  
Performance Indicators ◽  
New Products ◽  
Operational Performance ◽  
Supplier Integration ◽  
Lean Practices

Abstract This study investigates the influence of supplier integration and lean practices on operational performance indicators: cost, quality, delivery, flexibility and speed of new products introduction. The proposed relationships are analyzed using survey data from a sample of 112 medium-sized textile companies in Brazil. The results suggest that supplier integration is significantly and positively associated with the speed of new products introduction, while lean practices are significantly and positively associated with operational performance indicators, except delivery. In addition, supplier integration does not support lean practices for any of operational performance indicators tested.

scholarly journals Experimental and Numerical Analysis on Two-Phase Induced Low-Speed Pre-Ignition

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5063
Author(s):  
Norbert Zöbinger ◽  
Thorsten Schweizer ◽  
Thomas Lauer ◽  
Heiko Kubach ◽  
Thomas Koch
Keyword(s):  
Gas Phase ◽  
Cfd Simulation ◽  
Particle Temperature ◽  
Solid Particles ◽  
Two Phase ◽  
Engine Operation ◽  
Oil Droplet ◽  
Low Speed ◽  
Detailed Reaction Mechanism ◽  
Oil Fuel

The root cause of the initial low-speed pre-ignition (LSPI) is not yet clarified. The literature data suggest that a two-phase phenomenon is most likely triggering the unpredictable premature ignitions in highly boosted spark-ignition engines. However, there are different hypotheses regarding the actual initiator, whether it is a detached liquid oil-fuel droplet or a solid-like particle from deposits. Therefore, the present work investigates the possibility of oil droplet-induced pre-ignitions using a modern downsized engine with minimally invasive endoscopic optical accessibility incorporating in-cylinder lubrication oil detection via light-induced fluorescence. This setup enables the differentiation between liquid and solid particles. Furthermore, the potential of hot solid particles to initiate an ignition under engine-relevant conditions is analyzed numerically. To do so, the particle is generalized as a hot surface transferring heat to the reactive ambient gas phase. The gas-phase reactivity is represented as a TRF/air mixture based on RON/MON specifications of the investigated fuel. The chemical processes are predicted using a semi-detailed reaction mechanism, including 137 species and 633 reactions in a 2D CFD simulation framework. In the optical experiments, no evidence of a liquid oil droplet-induced pre-ignition could be found. Nevertheless, all observed pre-ignitions had a history of flying light-emitting objects. There are strong hints towards solid-like deposit LSPI initiation. The application of the numerical methodology to mean in-cylinder conditions of an LSPI prone engine operation point reveals that particles below 1000 K are not able to initiate a pre-ignition. A sensitivity analysis of the thermodynamic boundary conditions showed that the particle temperature is the most decisive parameter on the calculated ignition delay time.

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