Influence Of Rotational Speed Research Articles

Hydraulic Tests of the PZ0 Gear Micropump and the Importance Rank of Its Design and Operating Parameters

This article presents the results of hydraulic tests performed for a prototype gear micropump of a new design. The development of modern hydraulic systems is following two directions: the integration of hydraulic and electronic engineering and a reduction in the mass and the dimensions of the system. The scope of this research involved identifying static characteristics of the prototype gear pump, i.e., its efficiency, torque and power. The tests were performed for PZ0 pumps with the following specific deliveries (which are their design parameters), 0.25 cm3/rev, 0.315 cm3/rev, 0.5 cm3/rev, 0.8 cm3/rev, and 1.0 cm3/rev—with two different types of hydraulic oils, Azolla ZS 22 and HL 68. The operating parameters included the rotational speed, the discharge pressure and the flow rate. The obtained research results suggest an application of the decision tree induction-based classification method for identifying the most important design and operating parameters and their values influencing total efficiency. In addition, the article investigates the influence of rotational speed and specific delivery on total efficiency. The total efficiency translates indirectly into the energy consumption of the solution. The criterion of energy consumption is a key parameter for ecological and economical reasons, related mainly to future operating costs.

A novel active volumetric rotating disks solar receiver for concentrated solar power generation

• The complete analysis is composed by a CFD model and its experimental validation. • The experimental results fits with CFD model results. • Thermal performance shows promising results compared to the state of the art. • Next steps in the receiver development will be its upscaling. A new active, first of its kind, volumetric receiver prototype is used in this study to obtain the conclusions about its thermal performance. The rotating disks cooling, was studied first, numerically, using a CFD software and second, experimentally, using a laboratory-scale prototype. This study evaluates the convective heat transfer from rotating disks to a transverse air crossflow. The thermal energy exchange on the disk surfaces allows us to calculate the heat transfer coefficient from disk surface temperature and the thermal performance of the receiver prototype and local Nusselt number through the receiver depth are also a key point in the research. The influence of rotational speed and air mass flow on the heat transfer coefficient is also studied. Differences between numerical and experimental results show high concordance, with a relative error below 15% in the worst point. The thermal performance shown by the lab-scale receiver is promising for the further development of the active Open Volumetric Air Receivers (OVAR) technology. The obtained thermal efficiency results show an improvement of around 10% at 900 °C when compared to the current state of the art of volumetric receivers.

Sensitivity analysis on the influence factors of clearance axial force of a varying-speed centrifugal pump

Abstract Hydraulic axial force is an important parameter of the performance of centrifugal pump. It strongly affects the operation stability and the life-time of thrust bearing. Under the influence of flow pressure distribution, the hydraulic axial force of centrifugal pump has mainly two parts. One is the force inside impeller while the other is the force in clearance. In this case, the situation is more complex because the pump operates with varying-speed. Under the influence of rotation speed, pump head and minimum clearance width, the variation law of clearance axial force is still not fully understood. Therefore, the orthogonal experiment is conducted based on Large Eddy Simulation (LES). The local flow and hydraulic axial force in impeller shroud clearance is mainly studied. Results show that the pressure difference between impeller inlet and outlet will strongly impact the pressure distribution in clearance. Then, it affects the clearance axial force. The rotation speed and pump head are proved influential. However, range analysis shows that the minimum clearance width is the most dominant factor. It can somehow adjust the pressure distribution in clearance. The geometric design of impeller clearance will be important in reducing hydraulic axial force especially for varying-speed centrifugal pumps.

RETRACTED: Influence of rotation speeds on microstructure and mechanical properties of welded joints of friction stir welded AA2014-T6/AA6061-T6 alloys

This study presents the joining process of plates with thickness of 4 mm in AA2014 and AA6061 through Friction Stir Welding (FSW) process under alternative tool rotating speeds. AA2014-T6 and AA 6061-T6 alloys were friction stir welded with cylindrical eased pin tool at different revolving speeds such as 700, 900 and 1100 rpm and constant welding speed of 50 mm/min. Mechanical behavior of the FSW of an aluminum alloy exposes a key role of the microstructure. The microstructure change in the interfacial region is characterized using Optical Microscopy (OM). The average grain size was determined based on ASTM E112 – 12 standards. The mechanical properties like tensile strength, micro hardness, and flexural strength of the dissimilar aluminum alloys were evaluated. The fracture examination of the tensile samples was evaluated using Scanning Electron Microscope (SEM). Distance Amplitude Curve (DAC) shows that no recordable internal discontinuities are observed for all three weldments. Further, the study articulated that the effect of rotational speed (900 rpm) exhibits better hardness, tensile and flexural strength. In addition, there was a significant improvement in the grain structure and the average % of grain structure with an average grain size was found to be 15.6 µm and it directly influences the mechanical properties.

Influence of rotation speed, transverse speed, and pin length during underwater friction stir welding (UW-FSW) on aluminum AA6063: A novel criterion for parametric control

The development and demand for lightweight materials such as aluminum, magnesium, and their alloys have been significant in the aerospace and automotive industries. Friction stir welding (FSW) is an economical solution for establishing a good joint for these metals and their alloys. In the current investigation, the aluminum alloy plates of AA6063 were fused using underwater FSW using a D2 steel tool holder and an HSS tool with a conical pin. According to Box Behnken design (BBD), the welding experiments were based on Response Surface Methodology (RSM) with 15 tests. The process constraints were controlled by the Combined Compromise Solution (CoCoSo) based optimization module. The influence of transverse speed (TS), rotational speed (RS), and pin length (Pl) on mechanical performances such as Ultimate tensile strength (UTS) and hardness test (HRB) is investigated. The analysis of variance (ANOVA) demonstrated that the transverse speed, rotational speed, and pin length are the essential factors in determining joint soundness. After performing the confirmation run with the optimal parameters, the predicted optimal value of the welding response was verified. This study indicates that the proposed optimization module efficiently controls the varying process parameters to achieve conflicting response values. It is highly efficient to manufacture high-efficiency welded joints and is recommended for optimum joint qualities.

The numerical investigation of the rotation speed and Reynolds number variations of a NACA 0012 airfoil

Marine rudders are equipment that allows us to alter the direction of vessels together with the thrust provided by propulsion systems. Many factors influence the axial forces directed by marine rudders, including rudder form, rudder-propeller-hull interactions, hull velocity, environmental conditions, and rudder rotation speed. In this study, the hydrodynamic characteristics of a marine rudder with the NACA 0012 section are studied using computational fluid dynamics analyses in order to better understand the influence of rotational speed on the rudder and to determine its relationship with the Reynolds number. Commercial software ANSYS Fluent is used to perform RANS simulations for the investigation. Based on the cruising speed of ships, a wide range of Reynolds numbers were chosen to study with the appropriate rotation speeds ranging from 1 deg/s to 7 deg/s with a 2-deg/s step size. In a two-dimensional numerical domain, the RANS method is applied to determine the hydrodynamic behaviour of the rudder. Results obtained from numerical simulations were evaluated and interpreted comparatively. The changes in the Reynolds number and the rudder rotation speed affect the hydrodynamic forces and related coefficients acting on a marine rudder.

Post treated PEDOT-PSS films with excellent conductivity and optical properties as multifunctional flexible electrodes for possible optoelectronic and energy storage applications

Organic electronic devices with low cost, wearable and flexible electrodes have become forefront of scientific and technological development of optoelectronic research. Electrode fabrication techniques with superior multi-functionalities such as conductivity, optical transparency, and mechanical flexibility remains a biggest challenge for research community. Herein, we present a strategy to develop highly conductive, transparent and flexible electrodes based on post-treated Poly (3,4-ethylenedioxythiophene): Poly (styrene sulfonate) (PEDOT: PSS) films on a Polyethylene terephthalate (PET) substrate for possible optoelectronic and energy storage applications. Commercially available PEDOT-PSS doped with secondary solvent such as N,N-Dimethylformamide (DMF) was spin coated onto PET substrate followed by camphor sulphonic acid (CSA) post-treatment. Doping of DMF followed by CSA post-treatment significantly enhances the conductivity of PEDOT-PSS films from 1.5 S cm−1 to 1826 S cm−1. Optical transmittance of 87% was achieved in the post-treated PEDOT-PSS films in comparison to 92% for PET substrate. The influence of rotation speed, rotation time of coating unit, and number of fabricated layers on opto-electronic properties of post-treated PEDOT-PSS films were investigated in detail. Improved electrical conductivity, optical conductivity, dielectric constant, and refractive index associated with photon energies suggests significant removal of insulating PSS segments and formation of localized energy states within energy band gap of post-treated films. The post-treated flexible PEDOT-PSS films exhibit excellent stability interms of conductivity and optical transmittance for a period of 30 days under ambient conditions. Furthermore, the post-treated PEDOT-PSS films show improved electrochemical performance to be used as flexible electrode in supercapacitors. This study demonstrates an efficient strategy to fabricate highly conductive, flexible electrodes based on PEDOT-PSS films with superior optical and electrochemical properties for a possible optoelectronic and energy storage applications.

Influence of rotational speed on the electrical and mechanical properties of the friction stir spot welded aluminium alloy sheets

AbstractAn efficient and productive joining technique to weld aluminium has become a priority challenge for promoting the use of aluminium in the electrical industry. One of the challenges is to obtain welds with superior mechanical properties with the consistent quality of weld surface as well as low electrical resistance. In this paper, the influence of rotational speed during the friction stir spot welding of AA 5754-H111 was studied to analyse the mechanical and electrical properties of the welds. The results from two rotational speeds (1000 rpm and 4500 rpm) are presented and compared to the base material. It was observed that the samples welded at 1000 rpm showed a higher average shear failure load (~ 1.1 kN) compared to the samples welded at 4500 rpm (~ 0.94 kN). The microhardness of the samples welded at 1000 rpm was higher than that of the base material, while the microhardness of samples welded at 4500 rpm was lower. It was also found that the friction welded sheets, regardless of the rotational speed used, showed increased electrical resistance compared to the base material, albeit this increase for the samples welded at 1000 rpm was about 42%, compared to samples welded at 4500 rpm where this increase was just 14%.

Study on interface non-uniform slip of combined rotor considering real preload distribution

This paper studied the interface non-uniform slip phenomenon and proposed a characterization model. Firstly, by analyzing the mechanical status of combined rotor during operation, the generation mechanism of non-uniform slip is revealed. Then, the bolt preload is tested by ultrasonic testing system, and the non-uniform slip simulation based on measured preload distribution is carried out. Finally, by constructing the Generalized Gray Level Co-occurrence Matrix (GLCM) considering the preload distribution and extracting the corresponding texture features, a non-uniform slip characterization model is established. The paper discussed the influence of rotational speed and various coefficients on the characterization model, when the coefficients selection is reasonable, the model error is 2.11%. The research content strongly supports the study of connection structure dynamics.

Investigations on the effect of rotational speed on the transport of air-water two-phase flows by centrifugal pumps

This study presents experimental and numerical investigations on air-water flows in a centrifugal pump, extending our previous studies. The main objective of the present article is to examine the influence of rotational speed on pump performance. For that purpose, the pump performance was considered and extensively compared for two different rotational speeds, i.e., 650 rpm and 1000 rpm, covering different single and two-phase flow conditions. To allow flow visualization, the impeller and the pump body were manufactured from transparent materials, and a high-speed camera was employed for recording the two-phase flow regimes. The performance of the pump was illustrated and reported for either a constant gas volume fraction or a constant air flow rate at the pump inlet. The desired operating conditions at the inlet were achieved using various predetermined experimental procedures to study the performance hysteresis. Pump surging and breakdown conditions were also considered. Additionally, 3D URANS single-phase numerical simulations were performed to explain additional internal flow details. The moving-mesh approach combined with the k-ω SST turbulence model has been used for that purpose. The simulations agree well with the experiments in most cases. Overall, the results show that increasing the rpm enhances two-phase mixing, which leads to various and significant improvements regarding two-phase pumping performance.

Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM

The design of the cylindrical sieve equipment used for the screening and separation of agricultural granular materials is mainly through the experimental method, which has the disadvantages of a long development cycle and high cost. To solve this problem, the discrete element method (DEM) was utilized to accurately build the particle models of threshed rice components (grains, shriveled grains, and short stalks), and simulated the separation of grains from the mixture in a cylindrical sieve. The influences of rotational speed (A), cylindrical sieve diameter (B), cylindrical sieve aperture (C), and inclinational angle (D) on screening cleaning rate, screening loss rate, and screening efficiency were investigated. Meanwhile, the optimal parameters of the cylindrical sieve were obtained using a central composite design (CCD) under response surface methodology (RSM). The results of CCD showed that the quadratic multinomial model is credible and revealed that the cylindrical sieve aperture has a significant impact on the screening characteristics. It is predicted that the optimal values for screening cleaning rate, loss rate, and efficiency were 97.84%, 0.27%, and 85.38%, respectively, while A, B, C, and D were 23.6 r/min, 297 mm, 8.7 mm, and 2°, respectively. The experimental results using a real threshed rice mixture were found to be in good agreement with the optimal simulation results. This study proved a reliable research method and provides a design reference for the cylinder sieving systems for threshed rice or separation of other bulk material. Keywords: cylindrical sieve, threshed rice mixture, discrete element method, separation, rice, optimization DOI: 10.25165/j.ijabe.20221502.5150 Citation: Yuan J B, Wang J F, Li H, Qi X D, Wang Y J, Li C. Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM. Int J Agric & Biol Eng, 2022; 15(2): 236–247.

Drilling Parameters Analysis on In-Situ Al/B4C/Mica Hybrid Composite and an Integrated Optimization Approach Using Fuzzy Model and Non-Dominated Sorting Genetic Algorithm

In-situ hybrid metal matrix composites were prepared by reinforcing AA6061 aluminium alloy with 10 wt.% of boron carbide (B4C) and 0 wt.% to 6 wt.% of mica. Machinability of the hybrid aluminium metal matrix composite was assessed by conducting drilling with varying input parameters. Surface texture of the hybrid composites and morphology of drill holes were examined through scanning electron microscope images. The influence of rotational speed, feed rate and % of mica reinforcement on thrust force and torque were studied and analysed. Statistical analysis and regression analysis were conducted to understand the significance of each input parameter. Reinforcement of mica is the key performance indicator in reducing the thrust force and torque in drilling of the selected material, irrespective of other parameter settings. Thrust force is minimum at mid-speed (2000 rpm) with the lowest feed rate (25 mm/min), but torque is minimum at highest speed (3000 rpm) with lowest feed rate (25 mm/min). Multi-objective optimization through a non-dominated sorting genetic algorithm has indicated that 1840 rpm of rotational speed, 25.3 mm/min of feed rate and 5.83% of mica reinforcement are the best parameters for obtaining the lowest thrust force of 339.68 N and torque of 68.98 N.m. Validation through experimental results confirms the predicted results with a negligible error (less than 0.1%). From the analysis and investigations, it is concluded that use of Al/10 wt.% B4C/5.83 wt.% mica composite is a good choice of material that comply with European Environmental Protection Directives: 2000/53/CE-ELV for the automotive sector. The energy and production cost of the components can be very much reduced if the found optimum drill parameters are adopted in the production.

The Influence of Rotational Speed on Bonding Strength, Magnetic Properties, and Mechanical Properties of Fe3O4/ZrO2 Magnetic Composites

The Influence of Rotational Speed on Bonding Strength, Magnetic Properties, and Mechanical Properties of Fe3O4/ZrO2 Magnetic Composites

Design and performance testing of areca nut thresher machine using solid triangle spike tooth type

Technology for handling agricultural products from areca nut has received less attention. However, the economic potential of the areca nut is comparable to that of other palm trees. Threshing areca nut from the bunch is one of the procedures that must be completed to obtain high-quality betel nut. Therefore, this research aims to design and test an areca nut threshing machine that uses a solid triangle spike-type threshing tooth. This study uses an experimental manufacturing method in the workshop and laboratory testing. A detailed engineering drawing of areca nut thresher machine is a guide in carrying out the manufacturer. The influence of rotational speed on the threshing shaft (34 rpm, 42 rpm, and 50 rpm) was investigated to determine the machinery’s performance (percentage of threshing results, engine capacity, and fuel consumption). This study indicates that the areca thresher machine has been successfully designed with a diesel motor driving source of 6.5 hp, 2200 rpm. Applied a rotational speed of 50 rpm will give the best percentage of threshing products. The increase in rotational speed applied to the threshing machine will be in line with the rise in the engine capacity. In addition, the fuel consumption of a diesel engine from this thresher machine is 0.039 l/hr.

Analysis on the nonlinear lateral vibration of drillstring in curved wells with beam finite element

This study focuses on the nonlinear lateral vibration of drillstring in curved wells. One of the most important features of this work is that the drillstring dynamics in curved wells (including both vertical, deflecting and horizontal well structures) are modeled and presented in actual drilling engineering scale. In the proposed model, beam finite element (FE) method is employed to calculate the drillstring dynamics in curved wells. The model is solved by the generalized-α method and verified by reproduction of the field data. The model has coupled the lateral, torsional and longitudinal vibrations of the drillstring, while we only pay our attention to the nonlinear lateral vibration of drillstring in curved wells. The efficient length of lateral vibration of a field curved well is firstly proposed, and the influences of rotation speed, weight on bit (WOB), coefficient of friction (COF) and stabilizer (STB) on the lateral vibration of drillstring in curved wells are discussed.

Influence of rotation speed on motion accuracy of hydrostatic journal bearing

Influence of rotation speed on motion accuracy of hydrostatic journal bearing

Simulation of the frequency split of the fundamental air cavity mode of a loaded and rolling tire by using steady-state transport analysis

It has been found that when a tire deforms due to loading, the fundamental air cavity mode splits into two due to the break in geometrical symmetry. The result is the creation of fore-aft and vertical acoustic modes near 200 Hz for typical passenger car tires. When those modes couple with structural, circumferential modes having similar natural frequencies, the oscillatory force transmitted to the suspension can be expected to increase, hence causing increased interior noise levels. Further, when the tire rotates, the frequency split is enlarged owing to the Doppler effect resulting from the airflow within the tire cavity. The current research is focused on determining the influence of rotation speed on the frequency split by using FE simulation. In particular, the analysis was performed by using steady-state transport analysis which enables vibroacoustic analysis in a moving frame attached to tire in the frequency domain. The details of the modeling are described and results are given for a tire under different rotation speeds, presented in terms of dispersion curves that illustrate the interaction between structural and acoustical modes. The results are compared to those for static tires and tires spinning without translational velocity to highlight the effects of rolling.

An Analytical Model of a Rotating Radial Cantilever Beam Considering the Coupling Between Bending, Stretching, and Torsion

Abstract In this paper, the mode coupling between bending, stretching, and torsional deformations is mainly studied by presenting an analytical model of a rotating cantilever beam with pre-twist angle and arbitrary cross section. Equations of motion of the beam are derived using Hamilton's principle. The Coriolis effect due to the coupling of the bending deformation and stretching deformation, the eccentricity caused by inconsistency between elastic center and centroid, spin softening effect, stress stiffening effect, shear deformation, and rotary inertia are included in the model. Equations of motion are solved by the Rayleigh-Ritz method. The natural frequencies obtained by the proposed analytical modal are in good agreement with those obtained by finite element method (FEM) which proved the accuracy of the analytical model. Finally, the coupling between different mode components is studied in detail based on a quantitative method. The transformation/conversion between different mode components is revealed, the influence of rotational speed, setting angle, and pre-twist angle on this conversion mode is studied. Results show that a specific mode shape is usually composed of multiple mode components. The essence of mode coupling is the coupling between different mode components. The influence of rotational speed, setting angle, and pre-twist angle on the mode coupling is that they cause the transformation/conversion between different mode components.

Influence of tool rotational speed on mechanical properties of aluminium alloy AA 7075-T6 during friction stir welding process

ABSTRACT Influence of the rotational speed can be clearly seen by using field-emission scanning electron microscopy (FE-SEM). The influence of rotating speed on macro and microstructures, hardness, shear performance and failure mechanism of friction stir welding on AA7075-T6 Al alloy with a thickness of 5 mm was investigated. At the lowest rotational speed, the data show a significantly closer hardness distribution in the AA7075-T6 Al alloy plates used during the friction stir welding process. The presence of the Fe- compounds was observed in the fracture surface of the nugget zone through the microstructure analysis. In this experimental investigation H-13 steel tool is used for friction stir welding process.

Analysis of temperature field and convection heat transfer of oil-air two-phase flow for ball bearing with under-race lubrication

PurposeUnder-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow and heat transfer characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The purpose of this paper is to study these two characteristics, and then provide guidance for lubrication and heat dissipation of bearing with under-race lubrication.Design/methodology/approachIn this paper, a simplified three-dimension heat transfer model of ball bearing with under-race lubrication is established; the coupled level set volume of fluid method is used to track the oil-air two-phase flow, and the Palmgren method is used to calculate the heat generation. The influence of rotation speed and inlet velocity on oil volume fraction, temperature and convection heat transfer is investigated. A temperature test for under-race lubrication is carried out.FindingsBecause of the centrifugal force, lubricating oil is located more on the outer ring raceway. As the rotation speed decreases and the inlet velocity increases, the oil volume fraction increases and the temperature decreases. Furthermore, the area with high oil volume fraction has a large convection heat transfer coefficient and low temperature. The error between the simulation temperature and the test temperature is within 10%.Originality/valueThe research on the temperature field and convection heat transfer characteristics of under-race lubrication ball bearings at different rotation speeds and inlet velocities is rarely involved.