Cylindrical Blade Research Articles

A new design way for cylindrical blades with adjustable inlet blade angles

A new approach for cylindrical blade design is presented in this article. Authors of this article analyzed the main reasons which are responsible for the low efficiency of untwisted blades and found out that the shock losses along the blade leading edge are much higher than those of twisted blades. Furthermore, based on the analysis, this article proposed a new design approach that is different from the traditional one. This new approach can reduce hydraulic losses at blade leading edge and improve performance and efficiency of cylindrical blades. In the traditional design process, to draw blade projection in plan view, an incidence at intersection of blade leading edge and inner streamline on the meridional section is selected for calculating blade inlet angle accurately. Because the incidence and the blade inlet angle at the intersection of blade leading edge and outer streamline are formed automatically, the blade inlet angles at this point are not suitable for oncoming flow direction, generating noticeable shock losses at this place. In the new design program, blade inlet angles at both intersection points formed by blade leading edge and the outer, inner streamlines are accurately calculated. This makes the shock losses generated by blade leading edge be minimized. Moreover, in conventional design, the projection of blade pressure side into plan view consists of only one plane curve. In the new design way, projection of blade surface in plan view is composed of two curves joined smoothly and continuously. Two impellers with fundamentally identical geometrical parameters were designed and manufactured, and the only difference is that their cylindrical blades were calculated and configured by applying a traditional design method or a the new approach. Test findings from an open loop indicate that in a wide load range from 0.8 to 1.2 times design flow rate, both head and efficiency of the new pump were raised. Over the operating range, efficiency of the new pump increased by 0.5% to 2.7%. Particularly, for higher flow rate, pump performance was improved significantly, and the increase of efficiency at pump design point arrived at 2.7%. The results suggest that the new approach presented in this article offers an effective and useful means to improve performance of low specific speed pumps.

Study on rotating cylindrical blades device of vertical axis Magnus wind turbine

Study on rotating cylindrical blades device of vertical axis Magnus wind turbine

Study on rotating cylindrical blades device of vertical axis Magnus wind turbine

Study on rotating cylindrical blades device of vertical axis Magnus wind turbine

Study on cylindrical blades device of vertical axis Magnus wind turbine

Study on cylindrical blades device of vertical axis Magnus wind turbine

Hollow-fiber renewal liquid membrane extraction coupled with 96-well plate system as innovative high-throughput configuration for the determination of endocrine disrupting compounds by high-performance liquid chromatography-fluorescence and diode array detection

This paper describes a new configuration of the hollow fiber renewal liquid membrane (HFRLM) procedure for the high-throughput determination of the endocrine disrupting compounds 4-nonylphenol, 4-octylphenol, 4-tert-octylphenol, methylparaben, ethylparaben and bisphenol A using a 96-well plate system and high-performance liquid chromatography. In this configuration, cylindrical blades were adapted as a support for polypropylene membranes used as supported liquid membranes in the HFRLM approach. The proposed configuration exhibited important advantages including high-throughput, low solvent and sample consumption, and good analytical performance. The optimized extraction conditions were achieved with the use of a mixture comprised of 50:50 v/v 1-octanol:hexane as the supported liquid membrane, sample pH 5, extraction solvent 15 μL (hexane) and extraction time 45 min. The limits of quantification varied from 0.5 μg L−1 for 4-octylphenol to 15 μg L−1 for methylparaben and ethylparaben and the r2 ranged from 0.9908 for methylparaben to 0.9992 for 4-tert-octylphenol. HFRLM combined with the use of a 96-well plate provides an environmentally-friendly configuration. It offers good accuracy when applied to analyze water samples, with relative recoveries ranging from 72 to 130%, for 4-octylphenol and 4-nonylphenol, respectively, and precision varying from 1 to 14.3%, for 4-nonylphenol at 1.0 μg L−1 and bisphenol A at 8.0 μg L−1, respectively.

Effect of the blade loading distribution on hydrodynamic performance of a centrifugal pump with cylindrical blades

The effect of the blade loading distribution on head, radial force and pressure pulsation of a low specific-speed centrifugal pump with cylindrical impeller blades were investigated in the present study. Blade shapes were obtained by adopting the 1D inverse design method, impellers with different blade loading curves were obtained while the distribution of the blade loading was carefully tailored. Threedimensional URANS simulation method based on the Shear stress transport (SST) k-ω turbulence model was employed for the analyzation of flow patterns. Numerical results including the pressure distribution and velocity profile were validated by comparing with the available experimental data, and an acceptable agreement was obtained. Three typical parameters of the blade loading curve, including the location of the fore-loading point (mpre), location of the aft-loading point (mpost) and slope of the rectilinear segment (K), were analyzed. Results showed that the well-designed blade loading curve, such as the fore-loading impeller, can effectively reduce the pressure pulsation amplitude and the radial force. The significant effect of the variation of the aft-loading point on pump hydrodynamic performance was also investigated. Meanwhile, pressure and velocity distributions at different slopes of the blade loading curves show that the fore-loading impeller produces more uniform flow issuing from the impeller than that of the pump with aft-loading impeller, thus reduces the radial force and pressure pulsation of the pump.

Effect of a rough surface on the aerodynamic characteristics of a two-bladed wind-powered engine with cylindrical blades

We have reported the results of experiments on determining the drag coefficient and the thrust coefficient of a two-bladed wind-powered engine based on the Magnus effect with rotating rough cylinders in the range of air flow velocity of 4–10 m/s (Re = 26800–90000) for a constant rotation number of a cylindrical blade about its own axis. The results show that an increase in the Reynolds number reduces the drag coefficient and the thrust coefficient. The extent of the influence of the relative roughness on the aerodynamic characteristics of the two-bladed wind-powered engine has been experimentally established.

Experimental and numerical investigation of the cylindrical blade tube inserts effect on the heat transfer enhancement in the horizontal pipe exchangers

In this experimental and numerical study an attempt to enhance the heat transfer rate by cylindrical blade that form turbulence flow inside the exchanger pipe is carried out. The effects of the blade geometry are also examined to investigate heat transfer rate in experimented tube inserts. Experiments are performed in different blade spacing (Sy1,2,3 = 101–216–340 mm) and various blade angles (α1,2,3 = 0°–45°–90°). The water flow rate inside the tube is adjusted in three different ranges to approach intended Reynolds numbers (Re1,2,3 = 6000–11,000–17,000). Nusselt number, Reynolds number and effect of friction factor are investigated separately. For all experiments, the increase in Nu number due to used tube inserts is recorded and compared to each other and plain tube in the related profiles. It is concluded that installed tube inserts in the heat exchanger tube, led to a significant increase in Nu number and energy saving. Among different experimented cases, using mean value in various Re numbers, the highest Nusselt number was obtained at Sy1 = 101 mm which was 24% more than that of plain tube. This value was 18.7 and 8.3% for Sy2 = 216 and Sy3 = 340 mm respectively. By this way, according results for friction factor were 0.30, 0.19 and 0.14. The presented study has been simulated by ANSYS Fluent 16 software to analyze flow behavior and heat transfer characteristics.

Intensification of the rate of diffusion controlled catalytic and electrochemical reactions in a new stirred tank reactor with a multi cylindrical blade impeller

The liquid–solid mass transfer behavior of 8 cylindrical blade impeller it can act as electrode or catalyst support in a new stirred tank reactor was studied in relation to catalytic and electrochemical reactor design by the electrochemical technique which involved measuring the limiting current of the cathodic reduction of K3Fe(CN)6. Variables studied were blade length, impeller rotation speed, physical properties of the solution, effect of baffles, effect of immiscible liquids, effect of superimposed solution flow (continuous operation), effect of the distance between successive impellers in case of multi-impeller reactor and the effect of drag reducing polymers. The mass transfer data for single rotating impeller were found to fit the following equation:Sh=0.429 Sc0.33 Re0.42Superimposed solution flow and impeller separation were found to have little effect on the rate of mass transfer, baffles were found to increase the rate of mass transfer while the presence of immiscible liquid decreases the rate of mass transfer. Addition of drag reducing polymers (Polyox WSR-301) was found to reduce the rate of mass transfer at single impeller by a maximum of 15.8%. Examination of heavy metal removal from dilute solutions revealed that the rate of metal deposition agrees fairly with the prediction of the equation despite the presence of surface roughness and H2 evolution. The advantages of this reactor in conducting diffusion controlled catalytic and electrochemical liquid–solid reactions and liquid–solid reactions involving sparingly soluble reactants that to be dispersed such as gases, solid particles and immiscible liquids were highlighted.

Research on Manufacturing of Blade Screw in Solid-Liquid Separator

Blade screw propeller is used as the pushing and squeezing machine which is often used in the liquid separator for software materials. The core part of blade screw is stainless steel material with wide tooth, thin wall and other characteristics, and its processing method is different from the cylindrical surface spiral groove processing. Usually, its machining process is based on a certain forming technology to produce spiral leaf firstly, then welding leaves on the shaft. The cylindrical blade screw in test equipment adopts triangle method to calculate the blank dimensions. Variable cross section of the outer ring graph is realized by using the polar radius equation drawing in the drawing software.

Effects of Twisted and Cylindrical Blades on the Flow Characteristics inside Blade Inlet and Outlet for a Centrifugal Pump

In this paper, the performance between cylindrical and twisted blades are analyzed for the same centrifugal pump. The three-dimensional steady and unsteady flow fields under 0.7Qd, Qd and 1.3Qd are simulated. The blade inlet and outlet flow and pressure pulsation inside the centrifugal pumps are discussed by using mathematical statistics and frequency domain analysis methods. The research is verified by experiments. The results show that the twisted blade controls blade outlet better than cylindrical blade at small flow and design flow, cylindrical blade controls blade outlet better than twisted blade at large flow. In the blade inlet and outlet, as the flow changes, the instability of cylindrical blade loading is higher than that of twisted blade. The cylindrical blade inlet pressure is affected by the shaft frequency more than that of the twisted blade. At shaft frequency and blade frequency, pressure pulsation coefficient of cylindrical blade outlet is higher than that of twisted blade outlet. The cylindrical and twisted blades effect on the blade inlet and middle gradually accumulates, resulting twisted blade outlet has larger pressure pulsation. The result can guide the optimum design of centrifugal pump to consider the performance balance between twisted and cylindrical blades.

Microlaparoscopy in Urogynecology: LSH and Sacrocervicopexy

Study ObjectiveTo determine the feasibility of using only microlaparoscopic (3.5 mm) accessory instruments for performing laparoscopic supracervical hysterectomy (LSH) and sacrocervicopexy with the aid of a transcervically placed cannula for introduction of mesh and needles. DesignRetrospective evaluation of the first five cases of microlaparoscopic LSH with sacrocervicopexy (Canadian Task Force classification III). SettingCommunity teaching hospital affiliated with a major teaching hospital. PatientsFive women with symptomatic uterovaginal prolapse of stage II or higher. InterventionsLSH with transcervical morcellation followed by sacrocervicopexy with all 3.5 mm instruments using synthetic mesh with anterior and posterior extensions. Measurements and Main ResultsFour ports were made in all patients: a 5-mm infraumbilical port for the laparoscope and three 3.5-mm ports (right and left paraumbilical and suprapubic). LSH was performed using a 3-mm bipolar grasping device and reusable monopolar scissors. Resection of the uterus was also performed using monopolar scissors. Transcervical coring through the vagina was performed using a 15-mm serrated cylindrical blade with a central rod placed upward through the cervix, and transcervical morcellation was performed using an electromechanical morcellator. In all patients, sacrocervicopexy was performed successfully using Y-shaped polypropylene mesh, with PTFE sutures on the vagina and the sacral promontory. Reperitonealization over the mesh was performed using a running barbed absorbable suture. There were no intraoperative or postoperative complications in this group of patients. ConclusionLSH and sacrocervicopexy using 3.5-mm accessory ports is a feasible procedure with the use of transcervical morcellation and a transcervical access cannula.

Research on Impeller Blade Style of Stamping and Welding Multistage Centrifugal Pump

Impact of vane curve on hydraulic performance of the DQ100-64-22 stamping pump was researched by CFD simulation and experiments. The research results show that processing fillet at the connecting section of space blade and shafts only generates minor influence on the pump performance，but it can decrease incidence losses of the inlet flow. The cylindrical blade type has great influence on both inner flow field and hydraulic performance of pump in the high flow rate conditions. The research can supply a good support for the vane curve design and manufacture of stamping and welding multistage centrifugal pumps.

Geotechnical Characterization of Sakakini’s Palace Stones and Other Construction Materials, Cairo-Egypt

The understanding of the geotechnical problems and failure mechanisms of stone structures of Sakakini palace (1897 after century) entails a comprehensive study on the mechanical behaviour of the stones and other construction materials. In addition to micro analysis, geological and geomorphologic interests, several investigations on stone deterioration and engineering geology were performed, First phase included more sophisticated techniques, which provided additional information on particular aspects of site deterioration and it included laser induced breakdown spectroscopy (LIBs), electron probe micro analysis, micro XRD and XRF analyses, scanning electron microscope analysis coupled with EDX probing, transmission electron microscopy and grain size distribution analysis, permeability and pore size distribution of stone, mortars, core binders and other construction materials. Second phase included the determination of mechanical properties of building stones, such as compressive strength, modulus of elasticity, tensile strength, and shear strength. To arrive at reliable values for these properties, a suitable number of samples should be extracted, prepared for testing, and properly tested. The test results are then analyzed to establish the investigated stone properties. The testing program includes extracting seven cylindrical cores from the basement stone walls of Sakakini’s mansion in down townCairo. The cores are extracted using rotary cylindrical diamond blade coring machine. The top and bottom surfaces of every core were prepared to be flat circular surfaces perpendicular to the vertical axis of the core. Because the palace is museum and attractive places for the tourists, core sampling could be carried out only at a limited number of locations under official permission. For the purpose, cylindrical specimens with a diameter of 42 - 44 mm and height of 90 - 100 mm, prepared by the use of a core drilling machine and some collected blocks from the archaeological site under investtigation were taken to determine the bulk structure, physical, short and long-term mechanical properties of the stone and other construction materials in the laboratory. A number of specimens prepared from these blocks were employed for testing. Furthermore, limitation due to the number of blocks was overcome by the determination of the in situ characteristics of the stones by Schmidt hammer tests, geo-tomographic investigations and rock mass classification on some stone rock structures where testing has been permitted. The objectives of the study are to provide a characterization of micro structures and the mechanical properties of the stones of Sakakini’s Mansion; describe the required testing plan; describe the test results and conclude the values of the basic mechanical properties of the building stones. The following sections provide detailed descriptions of the steps taken to achieve the objectives of the study. The purpose of the present research is to provide recommendations regarding the strengthening and the safety of architectural heritage under long and short-term loading. For this purpose, a set of experimental tests and of advanced numerical analyses are to be carried out.

Study on a Novel Testing System for Aerodynamic Performance of Magnus Wind Turbine Blade

The method of texting a blade’s aerodynamic performance used for traditional wind turbine airfoils was making pressure measurement holes on surface of the blade, but Magnus wind turbine blade must rotated at a certain speed to generate lift and drag force, so the method was inapplicable. A novel experimental device for testing aerodynamic performance of Magnus wind turbine’s cylindrical blades had been investigated. This device, which consists of three parts: cylindrical blade, controlling system and testing system, could measure the lift and drag force generated by the Magnus effect on the blades. This paper mainly studied the testing system,including dynamometer and amplifying circuit. At last, the testing system was used in the experiment to test aerodynamic performance of the Magnus wind turbine blade. The results showed that the system could conduct the experiment on testing the lift and drag force on the Magnus wind turbine blades efficiently, and the system could also be used to measure the lift and drag force on traditional wind turbine airfoil.

A three-dimensional numerical study of the Magnus wind turbine with different blade shapes

Although the Magnus type wind turbine has many benefits over conventional blade-type wind turbines, it normally has low wind energy utilization efficiency. Therefore, it is important to seek effective ways of improving the Magnus wind turbine power performance in order to promote its application. As blade aspect ratio is a critical parameter influencing the Magnus wind turbine performance, a 3D numerical study of a Magnus type wind turbine which is equipped with cylindrical blades with different aspect ratios has been conducted in this paper. In addition, various cylinder shapes, including truncated cone and wavy cylinder, have also been used and their effects on the performance of the Magnus wind turbine are analyzed. Performance characteristics such as power, torque, and thrust coefficients of the Magnus turbine with different blade shapes are compared and discussed with the aim of identifying the desirable blade characteristics for this type of turbine.

On the definition of the secondary flow in three-dimensional cascades

The present article proposes a novel methodology to evaluate secondary flows generated by the annulus boundary layers in complex cascades. Unlike two-dimensional (2D) linear cascades, where the reference flow is commonly defined as that measured at midspan, the problem of the reference flow definition for annular or complex 3D linear cascades does not have a general solution up to the present time. The proposed approach supports secondary flow analysis whenever exit streamwise vorticity produced by inlet endwall boundary layers is of interest. The idea is to compute the reference flow by applying slip boundary conditions at the endwalls in a viscous 3D numerical simulation, in which uniform total pressure is prescribed at the inlet. Thus the reference flow keeps the 3D nature of the actual flow except for the contribution of the endwall boundary layer vorticity. The resulting secondary field is then derived by projecting the 3D flow field (obtained from both an experiment and a fully viscous simulation) along the local reference flow direction; this approach can be proficiently applied to any complex geometry. This method allows the representation of secondary velocity vectors with a better estimation of the vortex extension, since it offers the opportunity to visualize also the region of the vortices, which can be approximated as a potential type. Furthermore, a proficient evaluation of the secondary vorticity and deviation angle effectively induced by the annulus boundary layer is possible. The approach was preliminarily verified against experimental data in linear cascades characterized by cylindrical blades, not reported for the sake of brevity, showing a very good agreement with the standard methodology based only on the experimental midspan flow field. This article presents secondary flows obtained by the application of the proposed methodology on two annular cascades with cylindrical and 3D-designed blades, stressing the differences with other definitions. Both numerical and experimental results are considered.

Effect of inner structure of centrifugal separator on particle classification performance

This study investigated the effects of the inner structure of a centrifugal separator on particle classification performance. The typical inner structure of centrifugal separators is as follows: a blade, which consists of two orthogonal plates, is inserted into the centrifugal separator to create rigid fluid and particle rotations. The results of the present study demonstrate that centrifugal separator performance was significantly improved by attachment of a cylinder to the center of a conventional blade. Modification of the separator by attachment of the cylinder to the center of the centrifugal separator is expected to prevent the particles in the slurry from passing through the central axis of the centrifugal separator. Hence, the particles are subjected to greater centrifugal force. Both experimental and theoretical results demonstrate that particle classification performance increases as the cylinder radius increases. Thus, it is evident that attachment of a cylindrical blade to the center of the centrifugal separator allows for effective and highly efficient collection of extremely small-classified fine particles.

Aerodynamic study on straight, arc-swept and twisted stationary linear cascade blades

A computational investigation has been carried out on the effects of sweep and twist in stationary linear cascades. Circular arc sweep has been applied to the datum cascade of straight cylindrical blades, i.e. spanwise constant stacking line curvature was prescribed. Positive sweep was applied near the endwalls, and the sweep angle distribution was symmetrical to the midspan plane. The straight and the arc-swept blades were studied at low, near-design, and high incidence angles of the straight blading. Twisted versions of the straight and the arc-swept blades were studied for spanwise constant inlet flow angle. The studies demonstrated the benefits of circular arc sweep for both untwisted and twisted blade rows, such as local loss reduction and uniformisation of cascade outlet axial velocity profile. Blade twist was found favourable from the aspect of endwall separation zone reduction.

Design and Experimental Investigation of the Joints of Inclined Struts for the Widening of Bridge Deck Slabs

The widening of existing bridge deck slabs using inclined struts has been found to be an economical and aesthetically pleasing solution. The design of the joints linking the strut respectively to the deck slab and the web of the box with limited penetration or perforation of the existing structure is of particular interest. Five different original strut joint details were developed and experimentally investigated for three different strut inclinations. These joints were fabricated using fiber-reinforced mortar as well as steel plates and cylindrical studs and blades penetrating into the cover concrete.The test results showed that strut joint details with some penetration into the cover concrete provide significant strength and deformational behavior, and show much better structural performance than strut joint details relying only on friction at the interface surface. Also, the ultimate resistance decreases with the increasing joint inclination.Finally, it is shown that existing design criteria match the results obtained with the strut joint details relying on surface friction. However, as soon as the strut joint details penetrate into the cover concrete, the design criteria underestimate the strength and an improved design criterion is proposed.