Cone Cylinder Research Articles

Flow Characteristic of Axial Piston Pump with Conical Cylinder Block

To examine the flow characteristic of axial piston pump with conical cylinder block, a comprehensive mathematical model of flow condition within a single cylinder bore was developed by utilizing discrete approximation. Each step of the discrete analog was fallen into three successive phases with oil compressibility and classical orifice equation. Besides, the discharge flow equation of whole pump was obtained with lumped parameter method. Based upon this model, a simulation system was built in the simulation software. The novel aspect of this research is that analysis of cylinder block cone angle. From the result of numerical simulation, it can be concluded that cylinder block cone angle has a significant impact on the flow characteristics, and conical cylinder block design is more feasible than cylindrical cylinder block from a flow characteristic point of view.

Discharge Flow Ripple of Axial Piston Pump with Conical Cylinder Block

The discharge flow ripple is a crucial criterion for evaluating the piston pump. This research examines the discharge flow ripple of axial piston pump with conical cylinder block by developing a comprehensive mathematical model based upon the Bernoulli equation and the continuity equation. The novel aspect of this research is that it includes the analysis of cylinder block cone angle. From the results of this research, it can be concluded that cylinder block cone angle has a significant impact on the discharge flow ripple, and utilizing a conical cylinder block design is more feasible than cylindrical cylinder block from a flow ripple point of view. This conclusion can be used to guide the up-front design for the variable displacement pump.

Sensitivity and Optimization of Artificial Digestion in the Inspection of Meat for Trichinella spiralis

In many countries, the method of choice in inspecting meat for Trichinella spiralis infection is artificial digestion. We conducted a study of the sensitivity of the artificial digestion method recommended by the International Commission on Trichinellosis for detecting T. spiralis larvae in meat and of the effect of modifications of some procedures used in the method on its sensitivity. As part of this, we evaluated the effects on larval recovery of the vessels used for larval settling, sieve sizes, and temperatures at which larvae passed through the sieves, using larvae from T. spiralis-infected mice. We observed the effects on larval recovery of digestion duration and of modified artificial digestion by using 10-g samples of infected mouse muscle alone or mixed with uninfected pork. The percentages of larvae recovered with the respective use of separatory funnels and conical cylinders were 51.20% and 98.70%. The rates of recovery of T. spiralis larvae at 4 degrees C after passage through sieves of 425-microm mesh (No. 40), 250-microm mesh (No. 60), and 180-microm mesh (No. 80) were 98.42%, 90.59%, and 81.63%, which exceeded the 97.79%, 85.10%, and 61.12% rates of recovery of motile larvae at 40 degrees C and the 95.12%, 78.60%, and 44.16% rates of recovery of dead larvae at 90 degrees C. The larval recovery rate after digestion for 2 hours (96.18%) was greater than that after 0.5 hours (88.00%). We then examined a modified digestion method in which 10-g samples of pork mixed with 300 mL of digestive solution were digested for 2 hours at 43 degrees C followed by chilling of digest solution to 4 degrees C before passing it through a 425-microm mesh (No. 40) sieve and allowing it to settle in a 1-L conical cylinder. With this procedure, the modified method detected T. spiralis in samples of pork meat weighing 10 g and containing either 1 larva per gram or 0.1 larva per gram. Further validation of digestion method incorporating these modifications is required with the use of larger samples of infected muscle from species such as swine, which are routinely tested for T. spiralis for the purpose of food safety.

Fabrication and Operation Testing of an Air-cored Pulse Transformer for Charging a High Voltage Pulse Forming Line

A high voltage air-cored helical strip/wire type pulse transformer has been fabricated for charging of a high voltage pulse forming line. As a primary coil, copper strip of 25mm width was wound helically around a MC nylon cylinder. For a secondary coil, copper enameled wire of 1mm diameter was wound around conical cylinder in order to provide insulation between two windings. The coupling coefficient of 0.53 was obtained when two coils were combined coaxially in the insulation oil filled chamber. Voltage gain and energy transfer efficiency were investigated by varying the parameters of primary and secondary circuit. Test results shows that the voltage gain increases up to 17 with increasing the primary capacitance up to 200nF. And highest energy transfer efficiency of 44% was obtained when the dual resonant operation condition was nearly satisfied. The pulse transformer developed in this study can be used for charging the middle conductor of a Blumlein pulse forming line.

Transition to Taylor vortex flow between rotating conical cylinders

Transition to Taylor vortex flow between two conical cylinders, with the inner one rotating and the outer one stationary, is studied by the numerical method in this article. It is found that the basic flow becomes unstable with increasing of Reynolds number ( Re) above a certain critical value Re c=117 and with the further increase of Re to about Re=300, the first stable vortex is formed near the top of the flow system. The annulus is filled with six pairs of vortices at about Re=800. These are confirmed by experimental observations. Moreover, the local extreme values of pressure and velocity are reached at the adjacent lines between neighboring vortices or at the medium lines of large vortices. The local minimum values of velocity and the local maximum values of pressure are reached at the same point, whereas the local maximum values of velocity of the flow are assumed at the point of inflection for pressure.

The PenetraCone, a new robust field measurement device for determining the penetrability of cementitious grouts

One of the most crucial parameters for successful grouting is to ensure that the grout can penetrate the necessary apertures. For the most commonly used grout, cementitious grout, the available methods for determining the ability to penetrate apertures involves several measurements with different meshes or similar, which need to be evaluated. However, during the grouting process in the field there is rarely any time for evaluation and the most commonly used field method today stipulates a mesh width through which a certain volume need to pass. This implies that only an indirect measurement of the penetrability is performed. In order to perform direct and fast field measurements of the penetrability, a new, robust measuring device has been developed at Chalmers University of Technology in Gothenburg, Sweden. The device is named PenetraCone and the measuring part consists of a gap that is formed between two conical cylinders. The penetrability characteristics are measured by decreasing this gap as grout flows through. The gap is measured using a dial indicator gauge. Initial tests with the PenetraCone show that two characteristic gaps or widths can be evaluated. The width as the grout flow goes from continuous flow to dripping is termed b filter and when the flow stops completely it is termed b stop . The parameter b filter is related to the commencement of clogging or filtration of the cementitious grout. This means that for apertures larger than b filter the cement passes unrestricted but for narrower apertures filtration will commence. This filtration process will occur in apertures down to b stop , which indicates the smallest aperture that the cement can pass through and for apertures below b stop the cement will not penetrate at all. The device is easy to use and the tests show that consistent values are obtained. The accuracy seems good enough for use as a control of the penetrability of cementitious grouts in the field. For use in production, the PenetraCone should be placed on the grouting rig, after the mixer, so that direct measurements can be performed on the grout that will actually be used for grouting. By relating the measured parameters to the penetrability requirements, quick decisions regarding the quality of the grout can be made directly on the grouting rig.

Occurrence of Taylor vortices in the flow between two rotating conical cylinders

The behavior of the flow between two coaxial conical cylinders with the inner one rotating and the outer one stationary is studied numerically. Special attention is paid to the occurrence of Taylor vortices in basic flow and unsteady helical vortices. It is found that, in basic flow, the vortices occur in the direction toward smaller radius, while toward bigger radius in unsteady helical vortices; moreover, the unsteady helical vortices can coexist with unstable steady Taylor vortices. The results suggest that the behavior of conical flow is dominated by a competition between the meridional flow and radial flow. The effect of meridional flow is most significant at small apex angle or in basic flow and helical vortices, while the radial flow dominates the structure at larger apex angle or in steady vortical flow. In order to get better understanding the competition and the transition of Taylor–Couette flow to conical flow, a velocity angle related to velocity components is defined, and the pattern evolution of velocity, streamlines and the velocity angle are examined with respect to apex angle, as well as Reynolds number. Finally, the statistical properties of turbulent conical flow are investigated.

Heat transfer in a conical cylinder with porous medium

In this paper, numerical study of heat transfer in a conical annular cylinder fixed with saturated porous medium is presented. The heat transfer is assumed to take place by natural convection and radiation. The inner surface of conical cylinder is maintained at uniform wall temperature. The governing partial differential equations are non-dimensionalised using suitable non-dimensional parameters and then solved by using finite element method. The porous medium is divided using triangular elements with uneven element size. A computer software is used to solve the coupled momentum and energy equations in an iterative manner. The results are discussed for various values of geometric and physical parameters of porous medium with emphasis on cone angle of the cylinder. It is seen that the cone angle plays a vital role in heat transfer from the hot surface to porous medium.

Fabrication of an antireflective polymer optical film with subwavelength structures using a roll-to-roll micro-replication process

An antireflective optical film with subwavelength structures replicated by use of a roll-to-roll micro-replication process (RMRP) is investigated. Firstly, a single layer of a nanostructure on a polymer film is designed for an antireflection purpose by the finite difference time domain method in the visible light spectrum. Structures of a conical cylinder array, with spatial period of 400 nm, diameter of 200 nm and height of 350 nm, are numerically obtained. Then, such structures are fabricated by RMRP combining originated structure fabrication realized by deep ultra-violet lithography and dry etching, Ni mold electroplating and replication by using the roll-to-roll process imprinting into the flexible polyethylene terephthalate substrate. A nanostructure roller mold bonded with Ni molds has been successfully fabricated and coated with the self-assembly monolayer process for the purpose of fabricating an anti-adhesion film and improving the lifetime of the Ni molds. The duplicated nanostructure films show a good optical quality of antireflection (AR ⩽ 2.45% in a 400–700 nm spectral range) and are in good agreement with the theoretical predictions. The experimental results show that the developed process is a promising and cost-effective method for the continuous duplication of flexible devices with nano-scaled feature sizes used in nanophotonics by RMRP.

Improving Heat Transfer with Taylor Vortices in a Compact Modified Couette-Taylor Apparatus

A numerical study has been conducted to determine the effect of radial heating on the stability of Taylor vortices in a system formed by concentric conical cylinders. The outer conical cylinder is stationary while the inner conical cylinder rotates. Both conical cylinders have the same apex angle resulting in a constant annular gap. The study of the effects of the introduction of buoyancy on the flow properties has been accomplished by considering both conical cylinders to be isothermal, the inner conical cylinder at a higher temperature than the outer conical cylinder. The calculations are achieved by the use of a Simplified Marker and Cell algorithm using a staggered mesh grid. The investigation is concerned with radius ratios of 0.8 defined at the top of the flow system. The results have shown that the apex angle affected the symmetry of the flow structures and the heat transfer mechanism. It was revealed through the Nusselt number that the overall heat transfer increased when the apex angle was increased.

An Investigation of Wide-Angle Dense-Medium Cycloning for the Recovery of Metal and Aggregate from Fine Slag

An investigation was carried out to evaluate the feasibility of using wide-angle dense-medium cycloning to process a fine (‐600 μm) stainless-steel slag. The slag was characterized by size and density using a combination of sieving and pycnometer measurements. Separation testing was carried out using a laboratory dense-medium cyclone to concentrate the stainless-steel fraction and produce a low-metal aggregate material. The effects of cyclone geometry (cone angle, underflow diameter, overflow diameter, cylinder length, and vortex finder length) and medium density on cyclone performance were evaluated. A Plackett-Burman statistical design was used to determine the significant variables as related to recovery and purity of the metal and aggregate products. Based on these results, full-factorial designs were performed at two different medium densities. Regression models relating the significant variables to product recovery and purity were developed for both the metal and aggregate fractions.

Mechanical properties of tool steels with diffusion carbon and nitrocarbon layers

The present paper presents the results of metallographical investigation and wear tests of tool steel grades: hot work steels 4H5W2FS, AMS 6437E and cold work steels ASTM A681, Ch12FS. All surfaces were hardened by the Carbo process (carburising) and by the NiCar process (nitrocarburising). The thermochemical treatment was conducted in powder pack for durations of 6 h (carburising) and of 4 h in the case of nitrocarburising. Wear tests were conducted by the three cylinder cone method. Wear velocity was 0·58 m s−1, unit loads were 50 and 400 MPa, wear path was 3470 m. Oil SAE30 was applied at the rate of 30 drops/min−1. Factors investigated were: morphology, depth and microhardness of the cases obtained, their microstructure, as well as phase composition.

Computational analysis of a variable ejector flow

The present study addresses a variable ejector which can improve the ejector efficiency and control the re-circulation ratio under a fixed operating pressure ratio. The variable ejector is a facility to obtain specific recirculation ratio under a given operating pressure ratio by varying the ejector throat area ratio. The numerical simulations are carried out to provide an understanding of the flow characteristics inside the variable ejector. The sonic and supersonic nozzles are adopted as primary driving nozzles in the ejector system, and a movable cone cylinder, inserted into a conventional ejector-diffuser system, is used to change the ejector throat area ratio. The numerical simulations are based on a fully implicit finite volume scheme of the compressible, Reynolds-Averaged Navier-Stokes equations. The results show that the variable ejector can control the recirculation ratio at a fixed operating pressure ratio.

A Study on Flow Characteristics in a Spiral Flow Nozzle

A conventional Swirl jet is generated by applying a tangential force in the fluid injected to the nozzle. For this reason, the nozzle structure is complicated and the nozzle has a difficulty to manufacture. According to recent researches, it is known that a unique nozzle unit with an annular slit and conical cylinder can generate a spiral flow which is a kind of swirl flow without a tangential force in the jet. Pressurized fluid from the reservoir is supplied to an annular chamber and then injected into the convergent nozzle through the annular slit. In this paper, the effect Of the ratio of air pressure in the buffer to stagnant atmospheric pressure on the spiral flow field is investigated numerically. As a result, axial and tangential velocities increased with an increase of the pressure ratio. Furthermore, in case of the high-pressure ratio, the variation in axial and tangential velocities for a fully developed flow was caused by relatively high flow instability in the buffer area.

Growth of Conical Carbon Nanotubes by Chemical Reduction of MgCO3

Carbon nanotubes were synthesized by chemical reduction of magnesium carbonate with metallic lithium at 600 degrees C. The nanotubes with an average length of 13 microm and diameter of 60 nm are made of short coaxial conical cylinder tubular graphite sheets with their cone axis parallel to the tube axis, different from the ordinary carbon nanotubes, composed of concentric cylindrical graphite layers with their normal perpendicular to the tube axis. It is suggested that nanoscale rough surface of lithium formed at the interface between supercritical carbon dioxide and liquid lithium takes the roles of both the reductant for reduction of carbon dioxide to carbon and the template for growth of carbon nanotubes.

Buckling behaviour of imperfect ring-stiffened cone–cylinder intersections under internal pressure

Cone–cylinder intersections are used commonly in pressure vessels and piping. In the case of a cone large end-to-cylinder intersection under internal pressure, the intersection is subject to a large circumferential compressive force. While both the cone and the cylinder may be locally thickened to strengthen the intersection, it is often desirable and convenient to provide an annular plate ring at the cone-to-cylinder joint to supplement local thickening or as an alternative strengthening measure, leading to a ring-stiffened cone–cylinder intersection. Only limited work has been carried out specifically on ring-stiffened cone–cylinder intersections under internal pressure. This paper presents the first experimental study on such intersections. In addition to the presentation of test results including geometric imperfections, failure behaviour and the determination of buckling mode and load based on displacement measurements, results from nonlinear bifurcation analysis using the perfect shape and nonlinear analysis using the measured imperfect shape are presented and compared with the experimental results.

Dynamics of the helical flow between rotating conical cylinders

The stability of the helical flow in a system of coaxial rotating conical cylinders, the inner one rotating and the outer one stationary was experimentally investigated. The helical flow resulted from a Hopf bifurcation, which occurred only when the acceleration of the inner conical cylinder was smaller than 0.06 rad/s 2. When the rotational speed of the inner conical cylinder was increased, the transition to turbulence occurred following a succession of flow states: (i) three-dimensional laminar flow (TDLF), (ii) laminar periodic helical flow (LPHF), (iii) doubly periodic wavy helical flow (DWHF), (iv) weakly turbulent helical flow (WTHF) and (v) fully turbulent helical flow (FTHF). Time series obtained by an electrochemical method permitted the identification and analysis of the fundamental frequencies and their evolutions associated with each time-dependent flow state, using Fourier and wavelet transforms. Phase space analysis revealed the associated attractors constructed from the embedded time series. In the FTHF flow state, the fundamental frequency of the helical flow was observed to have a ratio to the rotational frequency of almost twice that of the one measured in the LPHF regime.

직접모사법을 이용한 극음속 대기 유동과 측면 제트의 상호 작용 해석

본 논문에서는 직접모사법을 이용하여 고 고도 희박 영역에서 로켓의 자세 제어에 필수적인 측면 제트 분사와 그에 따른 자유 흐름 유동과 측면 제트의 상호 작용에 대한 연구를 수행하였다. 밀도 차가 큰 자유 흐름 유동과 제트 유동을 동시에 모사하기 위해 입자 가중치 기법을 사용하였다. 두 수직한 평판 사이의 유동 및 측면 제트 분사에 의한 상호 작용 해석을 수행하였고 그 결과를 실험치와 비교하여 프로그램을 검증하였다. 좀 더 실제적인 로켓 모델로 blunted cone cylinder 형상에 대하여 받음각을 변화시켜가며 자유 흐름 유동과 측면 제트의 상호 작용에 대한 연구를 수행하였다. 표면 압력 차이의 분포를 기준으로 람다(lambda) 충격파와 후류의 영향을 토의하였다. 받음각이 있는 유동의 경우 leeward 방향으로는 제트와 자유 흐름 유동의 상호 작용이 약해지며, windward 방향으로는 상호 작용이 매우 강해지는 것을 확인할 수 있었다. The interaction between hypersonic free stream and side jet flow at high altitudes is investigated by using the direct simulation Monte Carlo (DSMC) method. In order to alleviate the difficulty associated with the large density difference between the free stream and the side jet flow and to simulate the two flows simultaneously, a weighting factor technique is applied. For validation, the corner flow over a pair of plates perpendicularly attached is calculated with and without a side jet, and the results are compared with experiment. For a more realistic configuration, the flow past a blunted cone cylinder shape is solved. The leeward or windward jet is injected into the free stream and the effect on the aerodynamic force and moment is observed at various flow angles. The lambda shock effect and the wake structure are studied in terms of the surface pressure differential. A higher interaction between the free stream and the side jet flow is observed when the side jet is injected in the windward direction.

DYNAMIC LOADS ON THE DRIVE SHAFT BEARINGS OF A SWASH PLATE AXIAL PISTON PUMP WITH CONICAL CYLINDER BLOCK

Variable displacement swash plate pumps are invariably used under conditions that involve heavy loads with variable flow demands. Swash plate pumps with conical cylinder blocks are now widely used in view of their good static and dynamic characteristics. However, drive shafts of these pumps experience dynamic loads due to the pressure forces transmitted through the body of the conical cylinder block to the supporting bearings. Dynamics of such rotating mechanism are quite interesting and should be considered in the design process of the drive shaft and the supporting bearings. A mathematical model is formulated for a 9-piston swash plate pump with conical cylinder block in order to evaluate the dynamic loads on the drive shaft. Results are presented and discussed.

Effect of acceleration on transition properties in a conical cylinder system

Visualization and spectral studies of the flow between two conical cylinders, with the inner one rotating, revealed different flow modes that were sensitive to the way in which the inner conical cylinder was accelerated until a specified angular velocity was attained. Control of the inner conical body rotation using a computer permitted the quantification and classification of the different flow modes obtained with regard to the non-dimensional acceleration rate d Re d t imposed, where Re is the Reynolds number. In the range of Reynolds numbers between 0 and 1000, a transition branch was observed during the transition from the laminar state, according to the acceleration rate d Re d t . For very slow acceleration of the inner conical cylinder speed, i.e. d Re d t < 6.8 , a helical downward motion settled in the flow system, while for higher acceleration rates, d Re d t ⩾ 6.8 , the first observed toroidal vortices were followed by an upward vortical motion. This motion stopped when the Reynolds number was increased, and steady Taylor vortices became established in the fluid column. These Taylor vortices became wavy for higher Reynolds numbers and acceleration. A study of the time dependence of these flow modes showed in particular that only a single periodic wavy mode exists in the range of Reynolds numbers investigated.