Conical Part Research Articles

Modular Open Chamber Stand for Biomass Densification Using the Example of Miscanthus × Giganteus Greef Et Deu

This article presents a modular open chamber stand which simulates the densification process that occurs in a single channel of a pelletising die. The results of the verification tests confirmed the suitability of this stand for determining the optimal geometry of the channel. The test material was the biomass of Miscanthus × giganteus which is considered to be a difficult material for pressure densification; therefore, it was decided that it would be a good material for verifying the stand. The stand consists of four modules: an introductory section with a diameter of D = 12 and 10 mm, a conical part with an angle of α = 10°, 20°, 30°, 40°, a cylindrical part with lengths L = 5, 15, 25, 35, 45 mm and diameter d= 8 mm and a pellet receiving module. The stand is able to heat the densification channel. Individual modules can be assembled into test combinations; this results in a change in channel geometry without the necessity to manufacture many singular channels. The optimum geometry of the channel for miscanthus with a moisture content of 13%, densified at 100 °C was determined. It should be a channel with D = 10 mm, α = 40° and L = 18 mm.

Investigation of hot combined extrusion of steel hollow conical parts

Investigation of hot combined extrusion of steel hollow conical parts

THE INFLUENCE OF THE ANGLE OF ENTRY INTO THE BELL-SHAPED TIP OF A SHORTENED ROUND SUPERSONIC NOZZLE OF A ROCKET ENGINE ON ITS IMPULSE CHARACTERISTICS

In gas-dynamic studies of rocket engines, much attention is paid to the characteristics of the nozzle — its geometry, momentum, losses, and manifestation of traction characteristics under various operating conditions. This work is devoted to the study of the influence of the entry conditions into the bell-shaped tip of a shortened nozzle on its gas-dynamic and impulse characteristics. We consider shortened nozzles with the same conical supersonic parts and the same total length of the nozzle but with different angles of connection of the conical part of the nozzle with the bell-shaped tip. When working at sea level, changing the angle of inclination of the forming bell-shaped tip does not significantly change the value of the static pressure at the corner point and the coefficient of nozzle impulse. This is due to the occurrence of flow separation at the corner point and the presence of a large-scale vortex. With a continuous flow in the nozzle during the operation of the rocket engine at altitude, the nature of the pressure distribution on the nozzle wall at the corner point differs when the angle of connection of the conical part with the tip changes, and the maximum value at the nozzle section is approximately the same. This fact is explained by the appearance of a hanging shock wave near the tip wall at small entrance angles (30°). The study examines the flow’s impulse characteristics in the nozzle under different pressure values at the inlet and the surrounding environment. The impulse coefficient in terrestrial conditions depends little on changing the tip and decreases with increasing pressure at the nozzle inlet. When working at height, there is a weak effect of changing the angle of entry into the nozzles on the momentum coefficient.

Influence of the shape of the anode assembly inner channel on plasma flow velocity

This article considers how the shape of the inner channel in the anode assembly affects plasma flow velocity in a plasma torch. Three different shapes of the anode assembly were analyzed, all with a conical confusor part of 50 mm in length: with a diameter transition from 12 to 6 mm, from 12 to 8 mm, and from 12 to 10 mm. A computer experiment was performed using the finite element method and then validated by the subsequent full-scale experiment on a laboratory plasma unit. The obtained results were verified. The verification outcomes showed a satisfactory convergence and were consistent with the published data. A review of the existing plasma unit designs for powder production, application of functional coatings, and surface modification was carried out. The software packages implementing the finite element method to solve these problems were examined. The study yielded practical recommendations for consumers and developers of plasma equipment and identified the shapes of the anode assembly enabling both supersonic and subsonic plasma flow regimes.

Hydro-mechanical deep drawing of conical components: Wrinkling behavior and process enhancement

This study explores the hydro-mechanical deep drawing process of a conical part through finite element simulations using ABAQUS software. The central focus is on investigating the occurrence of wrinkling during the forming process. Given the limitations in generalizing previous studies on wrinkling, there is a critical necessity to comprehensively comprehend and mitigate wrinkling behavior through an investigation into the interplay of various parameters. In response to the recognized challenge of minimizing wrinkles, an experimental setup with a hydro-mechanical deep drawing die was resented, aiming to validate and refine the simulation results. Additionally, a comprehensive study is conducted regarding the effect of fluid pressure, chamber pressure, pre-bulge height, friction coefficients, and sheet thickness on wrinkling behavior. The findings reveal that, at a pre-bulge pressure of 40 bar and a pre-bulge height of 2 mm, the minimum wrinkling height is observed to be merely 0.02 mm — the lowest recorded value. Notably, an increasing drawing ratio demands a 50% higher minimum chamber pressure to prevent wrinkling in the flange. Furthermore, a larger distance between the sheet and the die reduces the safe working range by approximately 57%, impacting the production of a wrinkle-free part. Conversely, elevating the pre-bulge pressure results in a 50% expansion in the safe working area for producing a wrinkle-free part. By explicitly stating the challenge of minimizing wrinkles, this study aims to contribute valuable insights into optimizing the hydro-mechanical deep drawing process for enhanced efficiency and improved product quality.

Analytical description of adjustment of rolls for manufacturing parts from elastic sheet material

The object of research is the process of bending sheet material, taking into account its springiness. When manufacturing sheet parts by bending from a completely elastic sheet, its shape is completely restored after the deformation stops, unlike an elastic sheet. Thus, when producing cylindrical parts by drawing between three rolls, the resulting radius of the cylindrical part will be larger than the calculated one. This phenomenon is evaluated by the coefficient of springing – the ratio of the calculated radius to the one obtained after partial expansion. When manufacturing conical parts, this approach cannot be applied, because the value of the radius is variable. The article applies the theory of surface bending from differential geometry. The curvature of the line on the surface has two components - normal and geodesic. When the surface is bent, the normal component changes, while the geodesic component remains unchanged. The magnitude of the normal component depends on the angle between the origin of the cone and its axis. So, for a cone with a base of radius R and an angle of 20°, the normal curvature is 0.94/R, and the geodesic curvature is 0.34/R. For cylindrical parts, the geodesic curvature of the cross-section (circle) is zero, so it is not necessary to take it into account. Usually, adjustment of rolls for the production of conical parts is carried out experimentally. The difference of the proposed approach lies in the elimination of this problem thanks to the decomposition of the curvature of the base of the cone into two components. This allows to calculate the settings of the rolls and thereby reduce their adjustment time. The parameters of the rolls and their mutual placement are calculated for the production of conical parts of the required size, taking into account their springiness. The field of application of the obtained results is the production of parts by bending flat metal sheet blanks

RESEARCH OF SUPERSONIC FLOW IN SHORTENED NOZZLES OF ROCKET ENGINES WITH A BELL-SHAPED TIP

The flow in a shortened nozzle with a bell-shaped tip is considered. A comparison of the wave structures of the supersonic gas flow in shortened nozzles with short and long tips formed by compression and stretching of the original bell-shaped nozzle for connection, respectively, with the long and short conical part of the base nozzle at the same nozzle length was carried out. Under operation conditions at sea level and low pressure at the nozzle inlet (P0<50·105 Ра), a large-scale vortex structure, starting from the corner point of the nozzle inlet, is observed in both nozzles. In addition, in the long tip, a small-scale vortex is observed on the wall near its cut. A barrel-shaped wave structure of hanging jumps with a closing Mach disc is formed in the flow in both nozzles, inside which a "saddle-shaped" wave structure of low intensity is noticed. In the separation flow in the tip (when Р0<50·105 Ра and Рн = 1·105 Ра), the pressure on the wall in the separation zone is slightly lower (by ≈ 5-10%) than the external pressure Рн. When the engine is operating in the upper layers of the atmosphere, the static pressure on the section of both tips is proportional to the pressure at the entrance of the nozzle. In the cross-section, starting from the axis of the nozzle to ~0.89 R/Ra (the ratio of the current value of the radius R to the radius of the nozzle wall at the outlet Ra), the pressure decreases to a value proportional to the pressure at the nozzle inlet. Then, it increases linearly to the value of the pressure on the tip wall, which is proportional to the pressure at the nozzle inlet. This is due to the wave structure of the flow inside the nozzle. It was established that with a decrease in the length of the nozzle conical part, the impulse coefficient of the nozzle decreases significantly for operating at sea level and slightly decreases for operating in the upper layers of the atmosphere. The results of calculations correlate satisfactorily with the experimental study results of the flows in shortened nozzles with a bell-shaped tip

Forming process chain for manufacturing complex conical-section profiled rings: On a co-design method

The final quality of complex conical-section rings depends on co-design of multiple processes in forming process chain. In this study, for a complex aeroengine casing ring with a large slope and a flange on its end, a co-design method of the forming process chain is put forward towards the objective of precision forming, which not only proposes a standard process route composed of multiple processes of upsetting, punching, rectangular ring rolling, loose tooling forging and profiled ring rolling, but also presents co-design methods of dies and blanks for all the processes. For profiled ring rolling, a design method of preformed blank that makes the blank and the target conical-section ring have the same axial volume distribution is proposed. By the method, the axial metal redistribution during the process can be alleviated greatly thus improving the forming stability and precision of the ring. Based on the geometric features of designed preformed blank, design methods of blanks and dies for loose tolling forging, rectangular ring rolling, punching and upsetting are proposed sequentially. In view of the key roles of loose tooling forging (manufacturing the preformed blank) and profiled ring rolling on the final quality of the conical ring parts, inherited FE simulations for these two processes are performed to verify the proposed design methods and determine appropriate design parameter. It is demonstrated that the proposed design method has significant advantages in improving forming precision. Besides, a suggestive value 1.5 of the rolling ratio for profiled ring rolling (a key design parameter) is given based on comprehensive consideration of multiple indicators such as ring roundness, deformation uniformity and forming load. The corresponding industrial experiments performed illustrate that a high forming precision of the conical-section aeroengine casing ring is achieved.

Experimental investigation of three-dimensional gas-solid flow in CFB cyclone separator using electrical capacitance volume tomography

The anisotropic three-dimensional flow field inside cyclone separators makes it challenging to capture the gas-solid flow characteristics, and the internal behavior of the cyclone separator remains not fully understood. The gas-solid flow characteristics inside a cyclone separator of the circulating fluidized bed (CFB) are investigated using electrical capacitance volume tomography (ECVT). The solid fraction, average velocity, and frequency characteristics of particles were extracted from ECVT images. The experimental results show that the number of turns for the dust strands spirals gradually increases as the inlet gas velocity Uf increases. The axial velocity of the particles in the cylindrical part of the cyclone separator is always greater than in the conical part. In addition, the difference in inlet gas velocity and particle size results in different particle flow characteristics in the CFB riser. It leads to the differences in the particle circulation rate and flow pattern in the cyclone separator.

Friction stir extrusion and mechanical alloying of LM13 casting ingot to produce LM28 tubes

Friction Stir Extrusion (FSE) is applied on the as-cast LM13 aluminum alloy to produce tubes accompanied with the microstructural modification. Then, the process was employed to transform LM13 to LM28 alloy by mechanical alloying by adding Si particles during the process. In addition, a numerical model on the Deform 3D software is developed to simulate the process and investigate the temperature and strain distributions at different zones as well as the material flow over the process. The experimental and numerical results show that the peak temperature and strain of 460 °C and 200 are attained in the zone 6–10 mm after the conical part finish, where the material completely enters the tube channel. The temperature and strain distributions were varying through the tube wall, and the result is that the average Si precipitates’ size in the wall inside reduced to almost 0.8 μm while is 2 μm at the center of the tube wall. Furthermore, the material flow from the primary cylindrical ingot towards the tube wall was not uniform in the sample cross-section due to tool design, and the velocity of material movement at various zones was different. Mechanical alloying of LM13 alloy, by the addition of Si particles in ∼6 %, transformed the alloy to LM28 by increasing the silicon content from 12.2 to 19.2 %. The ultimate compression strength of the LM13 base metal increased from 84.7 to 138.7 MPa and 158.2 MPa, respectively, for LM13 and LM28 by breakage of needle-like Si precipitates and fine dispersion of them in the aluminum substrate.

A new analytical model for force prediction in incremental sheet forming

A new analytical model for forming force prediction in the whole process of incremental sheet forming (ISF) is presented in this work. The modelling of contact region, thickness distribution and strain components are carried out as the basis for the prediction of vertical and horizontal forces. The effect of local contact behaviour and material deformation, as well as the behaviours of global bending, changes of deformation mode and contact condition are taken into account in the modelling of ISF force history. The force prediction model at both plane strain and biaxial tension condition areas is developed based on the differences in contact region and thickness distribution between these two different deformation states. Validated by ISF tests for a truncated cone and pyramid part with varying drawing angles, the prediction of force history captures well the fluctuation of different force components due to the change of deformation conditions and provides an insight into the material deformation mechanisms and the direct correlation to forming force characteristics of the whole ISF process. In a practical case, the model is successfully applied to the force prediction in ISF-based cranial plate manufacture. The model is also validated by a series of ISF tests with accurate force predictions of both the peak and stabilised forces.

Cold Drawing of AISI 321 Stainless Steel Thin-Walled Seamless Tubes on a Floating Plug.

The paper presents the results of an analysis of the process of drawing AISI 321 stainless steel thin-walled seamless tubes on a floating plug. The influence of the geometry of dies and plugs, drawing velocity, and lubricants on the possibility of carrying out the pipe drawing process without a loss of strength of the lubricating film and, consequently, disturbance of the forming process and tube cracking, and also on the temperature in the drawing process, the mechanical properties of the tubes drawn, and the microhardness and roughness of the inner and outer surface of the tubes was investigated. The parameters of the drawing tools used were as follows: angle of drawing dies α = 16° and floating plugs with angles of inclination of the conical part of the plug β = 11.5°, 13°, and 14°. The drawing dies and floating plugs were made of G10 sintered carbide. Drawing speed was varied over the range 1 to 10 m/min. The study used several lubricants. Tubes with dimensions (outer diameter D0, wall thickness g0 before drawing process) D0 = 19 mm, g0 = 1.2 mm and D0 = 18 mm, g0 = 1.2 mm were drawn to produce tubes with dimensions (outer diameter Dk, wall thickness gk after drawing process) Dk = 16 mm, gk = 1.06 mm on a drawbench with the same total elongation, while the diameter and wall thickness were changed. During the process, continuous measurements were made of the drawing force and temperature in the deformation zone and on the tube surface. It was found that the drawing process causes a decrease in the roughness parameters Ra and Rz of the inner surface of the tubes. Moreover, after drawing, an increase of 30-70% was observed in the microhardness of the tube material in relation to the microhardness of the charge material. Based on the test results, it can be concluded that the work of frictional forces is the main direction of optimization of tube drawing on a floating plug process of hard-deforming materials.

Fine-tuning ionic transport through hybrid soft nanochannels: The role of polyelectrolyte charge density distribution

This study investigates a hybrid nanochannel consisting of two cylindrical and conical parts coated with a soft layer exhibiting either of four different spatial distribution functions: constant (type I), exponential (type II), sigmoidal (type III), and soft-step (type IV). The Poisson–Nernst–Planck and Navier–Stokes equations are numerically solved using the finite element method under steady-state conditions. The research focuses on the modification of behavior and enhancement of performance in nanochannels inspired by nature. Considering the spatial variation in charge density distribution and the limited understanding of ion transport mechanisms, this study highlights the importance of modeling tools in advancing this field. The findings contribute to the development of effective strategies for controlling and manipulating the behavior of charged nanochannels. The results demonstrate that changing the decay length from 0.2 to 1 at a concentration of 1 mM leads to an increase in the rectification factor for type II up to 6.129, i.e., 5.7 times. Furthermore, varying NPEL/NA from 25 to 100 mol m−3 at Vapp=+1 V results in ionic selectivity of 0.9072, 0.2009, 0.1543, and 0.9031 for functions of type I to type IV, respectively. These findings not only enhance our understanding of ion transport mechanisms in hybrid nanochannels but also suggest that manipulating the charge density of the soft layer enables the production of intelligent nanochannels with applications in separation, diagnostics, and sensing.

Drying behaviour and visualization of surfactants after co-spray drying of surfactant-stabilized aqueous suspensions

Surfactants are widely used in many industries as dispersants or flocculants for suspensions. As the addition of low concentrations of surfactant is sufficient to execute their effect, they barely alter the formulation composition. In this research it was examined whether surfactants, in particular polysorbate 80 (PS80), were suitable as suspension stabilizers for co-spray drying of drug-filler combinations. Therefore, their drying behaviour at different process and formulation settings was studied and mapped by means of fluorescently labelled PS80. Co-spray drying of 10% w/w aqueous suspensions stabilized with 0.1% w/w PS80 resulted in excessive loss of sticky powder in the conical lower part of the drying chamber and the powder conveyor ducts. Up to 16% of powder was lost in the first transporter (i.e. the first part of the conveyor ducts). The amount of powder deposited in the first transporter, and by extension the stickiness of the recovered powder, was correlated with the presence of PS80 on the surface of the spray dried particles. Redistribution of free surfactant molecules during droplet drying depended on the process and formulation parameters. Enrichment of PS80 at the particle surface was most pronounced after co-spray drying of liquid feedstocks with low suspended fraction at process conditions favouring rapid droplet drying.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. EXPERIMENTAL VERIFICATION OF THEORETICAL FORMULAS IN COMBINED EXTRUSION

Cold combined extrusion of cups with a conical bottom part made of a hardening material is considered. The methods for performing specific calculations of the deforming force for various geometric parameters of free and constrained extrusion are demonstrated in detail. Comparison with the experimental data obtained during the extrusion of aluminum alloy AD1 shows the high accuracy of the derived calculation formulas. It is confirmed that for most of the working stroke, the force of the combined extrusion will be significantly less than the force of the traditional extrusion.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM PRODUCTION TESTS OF COMBINED EXTRUSION

The production testing of cold combined extrusion of glasses with a conical bottom part made of steel 12KH18N9T is considered. Preliminary technological calculations with the help of previously developed methods are demonstrated in detail. Production tests confirmed the high accuracy of the derived calculation formulas and the suitability of the developed methods for designing production technological processes.

A STUDY OF THE EFFECT OF SEMI-ANGLE OF CONE ON THE VIBRATION CHARACTERISTICS OF CYLINDRICAL-CONICAL COUPLED SHELL STRUCTURE

In this work, the effect of variation of semi-angle of the conical part on the vibration characteristics of cylindrical-conical coupled structure is investigated. The shell is made of polyester resin reinforced by continuous E-glass fibers. The case is analyzed experimentally and numerically for orthotropic shell structures. The experimental program is conducted by exciting the fabricated structure by an impact hammer and monitoring the response using an attached accelerometer for different semi-angles of the conical part.Software named SIGVIEW is used to perform the signal processing on the acquired signal in order to measure the natural frequencies and the corresponding mode shapes. The numerical investigation is achieved using ANSYS (Finite Element software) which was verified by the experimental results. Good agreement is achieved when comparing the experimental and numerical results. The maximum deviation in results was found to be (5.9%). The maximum relative nodal rotational and translational amplitudes associated with thefirst normal mode of the orthotropic and isotropic shells are noted for the structure of semi-angle of cone of 45o .

DESIGN AND PRODUCTION OF A DEVICE FOR BASING AND FIXING CONIC DETAILS IN SINE BAR MEASUREMENTS

The geometric features of the conical parts measured by a sine bar requires special devices for basing and fastening. Basing and fixing conical parts on a sine bar is a problem that can lead to deviations in measurements. In the presented study, a fixture for fixing and basing conical details when measuring with a sine bar is designed and manufactured. The device is designed to facilitate the work of the operator in fixing the workpiece during the measurement, which increases the accuracy of the measurements. The developed structure is designed using SolidWorks. After the completion of the 3D model, a choice of material and technology for 3D printing is made. After that, a 3D printer is used for its production. The manufactured device is tested in laboratory studies. The designed device is installed on the sine bar without changing the measurement methodology. The conducted experiments prove its workability and applicability.

CALCULATION OF GAS-DYNAMICS PARAMETERS AND STRESS-STRAIN STATE OF CELSIAN CERAMICS PRODUCTS

In the work using the finite element method, an analysis of the behavior of nose fairings made of radio-transparent ceramic materials of celsian composition was carried out. Determination of parameters of gas dynamics and stress-strain state was carried out using licensed ANSYS software. SSG Reynold Stress turbulence model was chosen for accurate air flow simulation. Geometric and finite element models were used to calculate strength and temperature fields. The analysis of the results of gas-dynamic calculations shows that at the point of transition of the conical part of the rocket into the cylindrical part, there is a sharp change in the flow conditions and a disruption of the flow in the range of speeds of 100-1100 m/s. As a result of modeling the distribution of temperature fields with the stated task, it was established that the temperature on the inner surface of the fairing differs from the temperature on the outer surface by no more than ±1 °C on average, and the maximum surface heating temperature does not exceed 550 °C. According to the results of calculations of the stress-strain state under temperature regimes that simulate the conditions of their operation, it was concluded that under the considered conditions the equivalent (≤ 69.3 MPa) and main (≤ 40 MPa) stresses occurring in the nose fairing are not exceed the bending strength limit for celsian ceramics (290 MPa). It can be observed that the maximum temperature difference in thickness corresponds to the part of the fairing with the minimum radius. Movements on the surface of the fairing do not exceed 0.25 mm, which is acceptable according to the specified parameters. The parametric model provides advantages in justifying rational technical solutions. Ultimately, the nose fairing, made of celsian ceramics, will maintain its integrity in real operating conditions. Keywords: radiotransparent celsian ceramics; nose fairing; finite element method; gas dynamics; thermophysical calculations; strength; stress-strain state

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. EXPERIMENTAL VERIFICATION OF THEORETICAL FORMULAS DURING EXTRUSION WITH INITIAL DEFORMATION BY DIRECT EXTRUSION, AS WELL AS A SHIFT OF THE CENTRAL REGION

Cold extrusion with initial deformation by direct extrusion, as well as with initial shear deformation of the central region of glasses with a conical bottom part made of a hardening material, is considered. The methods for performing specific calculations of the deforming force for various geometric parameters of free and constrained extrusion are demonstrated in detail. Comparison with the experimental data obtained during the extrusion of aluminum alloy AD1 shows the high accuracy of the derived calculation formulas.