Annular Groove Research Articles

Experimental and CFD investigation on the thermal performance of two phase closed thermosyphons: Effect of corrugated evaporator

The use of a corrugated pipe in a thermosyphon can extend its applications in confined spaces or limited displacements due to its the flexible characteristics. However, there has been limited research on the inner heat transfer mechanism of corrugated thermosyphons so far. This study experimentally investigates the heat transfer characteristics of thermosyphons with both corrugated and smooth evaporators under various filling ratios and heating temperatures. In addition, a computational fluid dynamics (CFD) model is developed to reproduce the phase change behavior and two-phase flow of the working fluid in thermosyphons. The experimental results reveal that thermosyphon with a corrugated evaporator exhibits superior heat transfer performance, achieving the lowest total thermal resistance of 0.0243 K/W, which is lower than that of the smooth evaporator under optimal conditions within the test range. Additionally, the corrugated evaporator also demonstrates improved stability and reliability. The simulation results indicate that the use of corrugated pipe makes the boiling state in the evaporator more chaotic and strengthens the boiling heat transfer to a certain extent. Additionally, in the region above the liquid pool in evaporator, surface evaporation of returning condensate is the main heat transfer mechanism in tradition thermosyphon. However, boiling occurs within the annular groove of corrugated pipe due to the presence of the working fluid, resulting in a similar heat transfer efficiency distribution as observed in the liquid pool boiling zone.

Wetting and Dewetting Behaviors of Droplets on the Nanoring Surface

AbstractThis study uses molecular dynamics simulations to investigate the wetting behavior of water droplets on a gold substrate with annular grooves. The research finds that droplet size and substrate hydrophilicity similarly affect wetting behavior. Enhanced hydrophilicity changes the velocity trend of droplet contact line movement, while droplet size impacts the magnitude of velocity change. Contact angle fluctuations are observed and analyzed theoretically based on Young's equation. The results provide insights into the relationship between droplet dynamics and surface structure, contributing to a better understanding of wetting processes at the microscopic level.

Study of the sealing performance of a high-speed deep groove mechanical seal thermodynamic lubrication model

PurposeThe purpose of this study is to investigate the sealing performance of different deep groove mechanical seals by considering the changing law of dynamic pressure effect and temperature gradient caused by high speed and high pressure.Design/methodology/approachA thermohydrodynamic lubrication model (THD) of the mechanical seal was constructed and solved using the commercial software FLUENT. The pressure and temperature distributions of the fluid under different groove types, as well as the sealing performance under different pressures, rotational speeds and sealing gaps, are obtained.FindingsThe annular groove (AG) can effectively reduce the temperature, and the T-type spiral groove (STG) can effectively inhibit the leakage. The increase of pressure and rotational speed leads to the enhancement of dynamic pressure effect and the increase of leakage, while the sealing gap increases and the leakage increases while taking away more heat. The choice of groove type is very important to the impact of sealing performance.Originality/valueIn consideration of the beneficial effect of deep grooves on cooling performance, the viscous temperature equation and the impact of the thermodynamic lubrication model are evaluated in conjunction with the sealing performance of four distinct groove types. This approach provides a theoretical basis for the optimal design of mechanical seals.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0184/

Enhancing spool valve sealing performance with an annular groove

Enhancing spool valve sealing performance with an annular groove

ВПЛИВ КІЛЬЦЕВИХ КАНАВОК ХОЛОДНОГО ОБТИСКУ НА ДОВГОВІЧНІСТЬ ПАНЕЛЕЙ КРИЛА З ФУНКЦІОНАЛЬНИМИ ОТВОРАМИ

This article studies in detail the method of cold extrusion annular grooves to solve the problem of aircraft fatigue life extension that reduces the fatigue life of aircraft wing panels due to functional holes. This method is a very simple and effective anti-fatigue manufacturing technology. In order to simulate the different wing panels with functional holes, the experiment is designed to extrude the specimen with different extrusion forces to obtain annular grooves of different depths. Fatigue tests are conducted on specimens with annular grooves. The test results show that: 1) Cold extrusion annular grooves can extend the fatigue life of wing panels with functional holes; 2) The fatigue life of wing panels with functional holes is affected by the depth of the cold extrusion annular groove. The fatigue life changes in an inverted "V" shape as the depth of the cold extrusion annular groove increases; 3) When cold extrusion annular groove depth is 0.26mm, the fatigue life of specimen with holes is maximum, and the fatigue life is increased by 2.35~32.9 times when specimen thickness is 5 mm

Making the diamond vortex phase masks for the METIS instrument

Direct observation of exoplanets and proto-planetary disks with the METIS instrument at the Extremely Large Telescope will provide new insights into the processes of planet formation and exoplanet atmospheres. This will be possible thanks to a powerful vector vortex coronagraph that can suppress the starlight to reveal faint signals around it. Here we present the process of making the phase masks at the heart of the coronagraph. These annular groove phase masks consist of deep sub-wavelength gratings in diamond that are etched using inductively coupled oxygen plasma with a strong bias. The METIS instrument requires a wider bandwidth than such components have previously been demonstrated for, leading to a grating design with higher aspect ratio and more vertical walls. To achieve this, the etch mask used for diamond etching was changed from aluminium to silicon and the plasma power was increased. We also improved on our method for reducing the grating depth of finished components to fine-tune them. Together with improved optical testing, this allowed us to produce the best vortex phase masks so far demonstrated for the astronomical N-band.

ANALYSIS OF THE FORM AND SURFACE OF DENTAL IMPLANTS

The aim of the work – to study the peculiarities of the shape and surface relief of the main types of dental implants. Materials and methods. 12 dental implants used in the medical practice of Ukrainian dental clinics were studied. The study of the shape and surface relief of the implants was carried out using a scanning electron microscope GSM-649 (Japan). Results. All implants in the apical part have the shape of a cone with threads and cutting grooves. The thread with a large profile is located in the apical part of the implant, has an average pitch of turns of 1.1±0.05 mm and a profile height of 0.3±0.02 mm. The thread with a small profile is located in the part of the implant near the neck, has a pitch of 0.4±0.02 mm and a profile height of 0.1±0.02 mm. The thread pitch of implants with a single profile is 0.8±0.05 mm, and the height of the profile is 0.2±0.01 mm. Threads with a triangular profile have a profile angle of 50.0±2.9 degrees. The highest roughness is the surface of the top of the fine profile thread with the height of micro-uniformities from 7.0±2.2 to 36.0±8.3 μm, the smallest roughness with the height of micro-uniformities from 3.0±1.1 to 14.0±6.1 μm have surface areas in the area of the implant neck. Conclusions. 50% of the examined implants were made with two thread profiles: a large one in the apical side and a small one closer to the neck, 50% – with the same thread profile from the apical end to the neck. In most implants, the thread with a small profile is made in the form of annular grooves. The large thread of the implants had a rectangular, rounded and triangular profile with one or two steps. In some implants, as they approach the neck, the shape changes and the height of the thread profile decreases. The shape of the profile of small threads in all implants was close to rounded. The implants had different surface roughness. The highest roughness was recorded on the surface of the top of the small profile thread, and the lowest – in the area without a thread in the area of the implant neck.

Graphene-Dielectric metasurface of asymmetric grooved disks for biosensing and surface roughness evaluation

In this paper, we propose a high-performance graphene-dielectric metasurface that is applied as an optical biosensor. The proposed metasurface is based on an array of asymmetric grooved silicon disks grown over a graphene sheet. The asymmetric silicon disks lead to the formation of a high quality factor (Q-factor) Fano resonance. In addition to the sharp resonance, the strong field confinement provided by annular grooves results in an enhanced light-analyte interaction and sensitivity of as high as 640 nm/RIU. According to the presented results, the biosensor exhibits a high linearity R2 value of 0.999 and low resolution of 1.56e-4 RIU. Furthermore, the proposed biosensor is polarization-insensitive with a figure of merit (FOM) as high as 784 RIU−1. To the best of our knowledge, this is the highest FOM ever reported for a polarization-insensitive biosensor. Such characteristics are promising for effective detection of biomolecules like hemoglobin. Finally, the effect of surface roughness on performance of the proposed biosensor is investigated where different resonance characteristics and sensitivities are obtained. It implies that the proposed structure as a multiparameter sensor could be applied for biosensing and also for evaluation of the amount of surface roughness due to fabrication errors.

Diamond Grinding of Ceramic Balls in an Annular Groove

Diamond Grinding of Ceramic Balls in an Annular Groove

Flow field analysis and structure optimization of liquid sodium hybrid bearing

AbstractLiquid sodium hybrid bearing is mechanical pump shaft bottom key support components, that play a balanced radial force of the impeller by fluid effect, in order to improve the bearing performance, based on the calculation model, simulation analysis, structure improvement and other aspects of analysis, this paper based on the theory of fluid mechanics of bearing finite element model for numerical calculation and analysis of flow field. Under different eccentricities and vibration velocities, the influence of structure improvement on bearing capacity is analysed. The results show that the bearing capacity of the liquid sodium hybrid bearing is mainly the hydrostatic bearing capacity, and the hydrodynamic pressure only plays an auxiliary role. After the improvement of the load‐bearing structure, the load‐bearing capacity is increased by 4%–7.3%. And the leakage is reduced by 27%–38% when the depth of the annular groove is 0.6 mm.

间断环面槽翅片管换热器传热与阻力性能数值模拟研究

间断环面槽翅片管换热器传热与阻力性能数值模拟研究

The Geometric Configuration of Lubricant Recesses of the Polymer Sliding Layer of the Bearing

Polymers have gained a foothold in the international market and are actively utilized at a large scale in various industries. They are used as sliding layers in various types of friction units. However, there is a lack of research on their deformation behavior under different design conditions. This work is focused on studying the influence of the geometrical design of lubrication recesses in a polymer sliding layer operating under conditions of frictional contact interaction. The article investigated an element of bridge-bearing steel plate with recesses for lubrication. Two geometrical configurations of recesses are studied: the annular groove and spherical well in the engineering software package ANSYS Mechanical APDL. Polytetrafluoroethylene (PTFE) is considered an elastic-plastic sliding layer. A comparative analysis of two models with different geometrical configurations of cutouts for lubrication, with/without taking into account its volume in the recess, has been conducted. The article establishes that in the absence of lubrication in the recesses, large deformations of the polymer sliding layer occur. This effect negatively affects the structure as a whole. Changing the geometry of the recess for lubrication has the greatest effect on the intensity of plastic deformations. Its maximum level is lowered by almost ~60% when spherical notches are used for lubrication instead of grooves. The friction coefficient of the polymer has a great influence on the contact tangential stress. At the experimental coefficient of friction, it is lowered on average by ~85%. The friction coefficient of the lubricant has almost no effect on the deformation of the cell (<1%).

Modulating the Acoustic Vibration Performance of Wood by Introducing a Periodic Annular Groove Structure

The acoustic vibration performance of wood affects the quality of many musical instruments, and the variability of wood causes obvious differences between individual timber samples. To mitigate the variations among the individual timber samples intended for musical instruments, in this study, we combined finite element simulation with experimental testing to investigate the effect of the periodic annular groove structure on the comprehensive acoustic vibration characteristics of wood. The results revealed that there are discernible correlations between the structural parameters of the periodic annular groove and the key acoustic parameters of wood, including the resonant frequency, equivalent dynamic modulus of elasticity, equivalent specific dynamic modulus of elasticity, equivalent acoustic radiation quality constant, and equivalent acoustic impedance. These relationships can be used to fine-tune the overall acoustic vibration performance of wood and harmonize the acoustic vibration characteristics among different timber specimens. The effects of the periodic annular groove structure on the five acoustic vibration parameters obtained through finite element simulations exhibited minimal differences to the corresponding results from experimental tests. Furthermore, there was a remarkably strong correlation between the outcomes of the finite element simulations and the experimental test results, with the coefficient of determination exceeding 0.99.

Individualized Design and Field Application of Annular-Groove Polycrystalline Diamond Composite Bit

Summary Aiming at the problems of slow drilling speed, low service life, and poor stability of conventional polycrystalline diamond compact (PDC) bits in deep formations that are difficult to drill, a new annular-grooved PDC bit is proposed. The bit adopts discontinuous tooth arrangement to set cutters, and a circumferential annular groove around the center of the bit is set on the bit body to form a fragile convex annular ridge at the bottom of the well, improving the bit’s ability to invade the formation and its rock-breaking efficiency. Combined with the formation characteristics of Shapai 11 well and Shixi 102 well in Xinjiang Oil Field, the PDC bit crown shape, annular-groove design, cutter selection, and other aspects are designed individually, and the dynamic rock-breaking and hydraulic characteristics of the annular-groove PDC bit are simulated and analyzed. Finally, two PDC bits with different diameters are developed—a Φ215.9-mm annular-groove PDC bit and the field application bit. The field application bit results show that compared with the bit in the same layer of adjacent wells, the mechanical penetration rate of the annular-groove PDC bit is increased by 29.8–176.7%, and the footage is increased by 142.5–273.1%. It is concluded that the annular-groove PDC bit can significantly reduce the rock-breaking energy consumption of the bit and improve the mechanical rate of penetration (ROP) of the bit. At the same time, the raised annular ridge can reduce the lateral vibration of the bit and extend the service life of the bit, which will accelerate the exploration and development of deep difficult-to-drill formations. It is of positive significance to reduce drilling costs.

CENTRIFUGAL PUMP ROTOR NUT

A centrifugal pump rotor is proposed with the impeller mounted on the shaft using two nuts of fixed interacting reciprocal conical surfaces. The scientific work relates to the field of pump engineering, namely, to one of the methods of locking the rotor nut used in the design of centrifugal pumps, various self-locking devices of mechanisms and structural elements of fasteners that prevent self-unscrewing. The self-locking nut includes a nut, a solid crown with an inner conical surface interacting with the annular groove of the nut itself and with an annular conical groove on the outer surface and, moreover, on one side of the annular groove of the nut itself with a conical outer surface, and the inner conical surface of solid crown is conjugated with the outer conical surface of the nut itself. The inner conical surfaces of the solid crown are connected to the outer ones – the nut with tension.

Exit-hole repairing in 7475 aluminium alloy welded joints based on refill friction stir processing

In this study, the refill friction stir processing (RFSP) method was utilised to repair a exit-hole defect located at the end of the friction stir welding (FSW) joints in 7475 aluminium alloy plate. The morphology, macroscopic defects, and mechanical properties of the repaired joints were investigated. The results demonstrate that the exit-hole was successfully refilled after RFSP. Material flow caused the refill voids, annular grooves, and un-stirred material defects. The maximum strength reached 415 Mpa, equal to 105% of the base defect-free weld. The mechanical properties of repaired joint were largely influenced by the stir zone (SZ) boundary and un-stirred material defects.

Comparative analysis of quasi-static penetration characteristics of slotted granite and intact granite

The stress release method with rock slotting in the bottom hole by ultra-high-pressure water jet is proposed as a solution to the problem of increased rock strength due to high in-situ stress. However, the failure mode of rock with annular grooves under the simultaneous action of geostatic stress and hydrostatic pressure is still unclear. The failure characteristics, penetration force, failure mode and deformation characteristics of rock under geostatic stress are studied by numerical simulation. The results showed that the presence of an annular groove changes the rock failure mode. The radial crack propagation direction dominated by extrusion shear is deflected and will be connected to the peripheral area of the groove’s bottom. It becomes the primary crack propagation dominated by tensile shear, controlled by the crack formation zone and the stress concentration zone at the peripheral area of the groove’s bottom. The annular groove can significantly reduce the peak penetration force by about 72%. There is a critical value for the influence of groove depth on the peak penetration force. The presence of an annular groove changes the load-penetration curves from ductile failure to brittle failure mode. The groove modifies the stress propagation mode, altering the rock response and crack propagation zones. In addition, the annular groove decreases the radial force that restricts the extension of rock in the surrounding area, allowing the rock to expand more easily in the surrounding area. Therefore, this stress release method and the study’s findings are instructive for improving rock-breaking efficiency and gaining a deeper understanding of the technique.

Fluid-solid coupling simulation study on fuel leakage and deformation characteristics of precision coupling component in common rail injector and influence of pressure equalizing structure

In the foreseeable future, the use of fossil energy is still irreplaceable, makes efficient use of fossil energy and reduce emissions became important topics. Diesel engines have a very high share in the transportation field, and high-pressure common rail system has highly improved the performance of diesel engines. As the most important component of common rail system, the performance of common rail injector directly affects the engine. Precision coupling components are composed of moving parts with very precise clearance fit in the injector. With the wear of parts, fuel leakage of precision coupling components may reach the same level as injection quantity, which will seriously affect the injection pressure actually established, and then affect the power, efficiency, and emission performance of diesel engine. Many researchers have studied fuel leakage of precision coupling components, and put forward different methods to reduce fuel leakage, including improving the machining accuracy and machining annular grooves on parts. However, the wear of parts makes it a high-cost and low-effective method to improve machining accuracy. Besides, researchers have not fully considered the deformation of parts. In this work, fluid-solid coupling simulations were performed to analyze deformation and static fuel leakage characteristics, and to investigate effects of pressure equalizing structure on deformation and leakage of precision coupling component in common-rail injector. Different from the previous researches, the influence of machining the annular groove on the plunger sleeve instead of on the plunger, and influence of coexistence of annular groove and deformation were considered. The results show the deformation characteristics of the parts, the fuel flow characteristics in the gap, and the influence of the annular groove on the fuel leakage. The connection between the deformation of parts and fuel leakage, and potential methods to reduce the leakage are also discussed.

Numerical study on the influence mechanism of different types of burst disc on high pressure hydrogen spontaneous combustion in tube

High-pressure transportation and storage are the current main methods for storing hydrogen. Burst discs, which are common in high-pressure storage devices, can cause hydrogen leaks to ignite and create serious accidents when certain conditions are met. To investigate this, this paper studies the effect of different blasting slot shapes on the spontaneous combustion of leaked high-pressure hydrogen. Numerical simulations, using LES, EDC model, Ten-Step Burst Disc Opening Method and 19-Step Detailed Hydrogen Combustion Mechanism, were conducted to analyze the spontaneous combustion of hydrogen with annular grooves, star grooves, cross grooves and grooveless burst discs. The results of the study show that the shape of the groove in the bursting disc will significantly affect the shock wave structure and spontaneous combustion time of leaked high pressure hydrogen in the tube. Among the four types of bursting discs, the order of spontaneous combustion in the tube is annular groove (approximately 90 μs), star groove (approximately 110 μs), cross groove (approximately 120 μs), and grooveless bursting disc (approximately 130 μs). Secondly, the double spherical shock waves produced by annular groove bursting disc collide with each other, resulting in a higher rising speed of pressure and temperature in the tube than with other bursting discs. Finally, the spontaneous combustion time of the leaked hydrogen is proportional to the open area of the bursting disc. When the opening area is the same, the smaller the exit shape coefficient is, the shorter the spontaneous combustion time is. The research results can provide some reference for the design and application of bursting disc in high pressure hydrogen storage equipment.

TECHNICAL SOLUTION OF PROBLEMS ARISING ON THE SUCTION AND DISCHARGE VALVES OF THR DRILING PUMP

The purpose of the article is to extend the operational life of piston pumps by making beneficial modifications to the suction and discharge valves. The most common cause of mud pump failures is the wears on the valves so there is an urgent need to increase the durability of the inlet and outlet valves. This research will allow us to: - lengthen the functional life of the suction and discharge valves. - develop the mud pump's technical requirements. - enhance the drilling pump's economic effectiveness. Thus, it makes sense to do study on piston mud pump valves in order to improve the technical parameters by making some positive adjustments. A moved forward valve situates which essentially diminishes the affect stretch caused by the effect of a piston pump valve body contrary the valve situates. The valve situate comprises a by and large round and hollow body parcel portion parcel with a fixing surface which is slanted from the external surface of the round and hollow body parcel toward an insides throat of said round and hollow body parcel. The valve body comprises a for the most part disc-shaped parcel and a truncated funnel shaped parcel. An elastomer embed is gotten in a groove within the valve body. The cone shaped parcel of the valve comprises an inclined confront, counting a metal parcel and an elastomeric parcel shaped by the elastomeric embed. Within the valve situate of the present innovation, an annular weight alleviation groove within the round and hollow body parcel of the valve situate permits the inclined confront of the valve situate to flex subsequently calming a noteworthy sum of the affect stack between the restricting confront of the valve gathering. Keywords: suction valve, discharge valve, valve wears, valve seat, poppet valve, piston mud pumps.