Improvement of Suction Performance Using Splitter Impeller and Inducer

2017 ◽  
Author(s):  
K. Hayashi ◽  
S. Konno ◽  
M. Hayakawa ◽  
Y. Kawata
Keyword(s):  
Flow Rate ◽  
Industrial Applications ◽  
Flow Coefficient ◽  
The Other ◽  
Suction Pressure ◽  
Test Results ◽  
Pressure Condition ◽  
The Many ◽  
Suction Performance ◽  
Onset Of Cavitation

Suction performance is one of the most important characteristics of the industrial pump to keep the pump capability against the cavitation under the low suction pressure condition. Inducers have been developed to improve the suction performance of pumps. They are used for rocket turbo pumps and recently for many industrial applications. It is one of the competitiveness of the industrial pumps to downsize the scale with higher rotational speed by adopting inducer. The authors had proved that pump with splitter impeller with inducer can further improve the suction performance. The splitter impeller was specially designed to be resistant to the cavitation choke. The other very important requirement for the pump against cavitation is that it does not occur cavitation surge. The cavitation surge arises at the partial flow rate of the pump. In contrast to this the suction performance become better at the partial flow rate. So the precise compromise is necessary to satisfy these requirements. This paper presents the experimental and CFD results to improve and optimize the suction performance without generating cavitation surge. The many design and combination of splitter impeller and inducer are tested to get the better performance. The test results of pumps with different inlet flow coefficient are compared not only suction performance but also the onset of cavitation surge.

Control of Self-Excited Oscillations in Centrifugal Blowers

2007 ◽  
Author(s):  
Saad A. Ahmed
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Critical Mass ◽  
Industrial Applications ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Flow Area ◽  
The Stability

Centrifugal compressors or blowers are widely used in many industrial applications. However, the operation of such systems is limited at low-mass flow rates by self-excited flow instabilities which could result in rotating stall or surge of the compressor. These instabilities will limit the flow range in which the compressor or the blower can operate, and will also lower their performance and efficiency. Experimental techniques were used to investigate a model of radial vaneless diffuser at stall and stall-free operating conditions. The speed of the impeller was kept constant, while the mass flow rate was reduced gradually to study the steady and unsteady operating conditions of the compressor. Additional experiments were made to investigate the effects of reducing the exit flow area on the inception of stall. The results indicate that the instability in the diffuser was successfully delayed to a lower flow coefficient when throttle rings were attached to either one or both of the diffuser walls (i.e., to reduce the diffuser exit flow area). The results also showed that an increase of the blockage ratio improves the stability of the system (i.e., the critical mass flow rate could be reduced to 50% of its value without blockage). The results indicate that the throttle rings could be an effective method to control stall in radial diffusers.

scholarly journals Introduction of Balinese Script Handwriting Using Zoning and Multilayer Perceptron

2019 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
I Komang Arya Ganda Wiguna ◽  
Agus Muliantara
Keyword(s):  
Character Recognition ◽  
Extraction Method ◽  
Handwriting Recognition ◽  
The Other ◽  
Test Results ◽  
The Difference ◽  
Hidden Layer ◽  
The Many ◽  
Offline Testing ◽  
Value Of Learning

Handwriting identification is one out of the many research ever conducted. In its development, the handwriting can be written in real time by the user by using the mouse (online character recognition). Various studies on the traditional character handwriting recognition continue to be developed. One of them is the recognition of the Balinese characters. Balinese characters have their own unique characters compared with the other regions. The difference between the shapes of the characters with the other characters are quite similar, or there are some characters that can only be distinguished by a small sketch or doodle.This study uses Artificial Neural Network with Backpropagation algorithm to perform the Balinese characters recognition and zoning as a method of feature extraction. In a variation of the extraction method, the characteristics used are Image Centroid and Zone (ICZ), Zone Centroid and Zone (ZCZ) and normalization of features. Of the three methods, it will be determined the best method used in the Balinese characters recognition.From the test results of the extraction method, the combined characteristics of the ICZ, ZCZ and normalization of features were the most effective to be used for the recognition of the Balinese characters. The level of accuracy obtained from the results of the online testing was 71,28% and 72,31% for offline testing, with parameters of Backpropagation, which used the value of learning rate of 0,03, a momentum value of 0,5 and the number of neurons in the hidden layer of 130.

Fluid Dynamics Investigation on the Body Structure Inside a Sleeve Regulating Valve

2020 ◽  
Author(s):  
Jia-yi Wu ◽  
Yang Yue ◽  
Jia-ming Yang ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Industrial Applications ◽  
Original Model ◽  
The Body ◽  
Flow Coefficient ◽  
The Other ◽  
Body Structure ◽  
Fluid Force ◽  
Relative Increment ◽  
Optimized Model ◽  
Overall Performance

Abstract The sleeve regulating valve is a typical flow regulating component, which is indispensable in various industrial applications. This work investigates the effects of the body structure on the overall performance and the flow characteristic of a sleeve regulating valve. The anterior cavity h, the diameter of the center cavity Dc, and the eccentricity of the center cavity e are studied in a parametric way. When the relative increment of h, Dc, and e all take the value of 0.15, the rated flow coefficient Kve of the optimized valve is promoted by 33.99% relative to the Kve of the original model. The optimized model presents less wear between the valve core and the sleeve relative to the original model. It results from the fact that the non-centrosymmetric pressure distribution is reduced on the valve core. Besides, the optimized model has smaller lateral fluid force imposed on the valve core FL than the original model when the relative travel L/Lmax > 0.625, and they have close FL in the other range. Also, the optimized model has larger axial fluid force imposed on the valve core FA than the original model when L/Lmax > 0.875, and they have close FA in the other range.

scholarly journals Achievement in Training: Recorded Video Compared to Face-to-Face Environments

2021 ◽  
pp. 1-3
Author(s):  
Kate Quigley
Keyword(s):  
Student Achievement ◽  
Instructional Methods ◽  
The Other ◽  
Test Results ◽  
Face To Face ◽  
Video Lectures ◽  
Significant Difference ◽  
Similar Vein ◽  
The Many ◽  
Full Face

During the 2020-2021 years, it has been necessary for organizations to rethink how they conduct their daily operations in light of COVID-19 restrictions. One of the many activities within organizations is to provide new and recurrent training to their employees. In a similar vein, universities also had to make adaptations to instructional methods. This change provided an opportunity to compare student achievement in two different instructional modalities; one with lectures delivered in a full face-to-face format, and the other with recorded video lectures delivered in online platform. Both formats were conducted in morning and afternoon sessions. Three sets of test results were measured to compare the outcomes between two years. This study had mixed results, two of the three test results sets between the years showed no significant difference between face-to-face and recorded video lectures, while one of the three test results provided evidence that the results were different between instructional methods. The results of this study could provide applicable information to organizations and help to provide a roadmap for providing training in different formats. It is noteworthy that providing instruction in recorded video formats could be less expensive to organizations and also provide more flexibility for employees to fit recurrent t into their daily schedules.

scholarly journals Effect of Jetpump Throat Diameter and Secondary Discharge on Suction Pressure and Pump Efficiency

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Fatkhur Rohman Eka Candra Wijaya
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Pump Efficiency ◽  
Suction Pressure ◽  
Test Results ◽  
Low Speed ◽  
Mixing Chamber ◽  
Throat Diameter

The throat diameter is one of the main parts of the jetpump, the throat diameter is a mixing chamber which has the function of mixing low-speed secondary fluids with high-speed primary fluids. The purpose of this study was to determine the effect of the throat jetpump diameter with a variation of 7,9,11 mm and secondary discharge with a variation of 10,15,20 L / minute on the suction pressure and pump efficiency. The highest test results were variations in the throat diameter of 11 mm and secondary discharge of 20 L / minute with a net discharge of 3.8 L / minute, an average discharge of 23.8 L / minute, a suction pressure of -0.25 and an efficiency value pump by 50%, the larger the throat diameter the greater the flow rate obtained.

Advancing Suction Performance in Hydrocarbon Liquids

2009 ◽  
Author(s):  
Kevin A. Kaupert ◽  
Keijun Kamio
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Superior Performance ◽  
Centrifugal Impeller ◽  
Test Results ◽  
Variable Pitch ◽  
Constant Pitch ◽  
Entire Flow ◽  
Flow Rate Range ◽  
Suction Performance

Details are presented on design investigations to advance the suction performance of inducers combined with centrifugal impellers for pumping liquid hydrocarbons such as liquefied natural gas (LNG). In particular minimizing the NPSHr3 is emphasized over the entire flow range. Design advances are made with the combined efforts of computational fluid dynamics, analytical methods, and test results. In particular the focus here is on inducer flow incidence and resulting blade loading by examining the NPSHr3 performance of the variable pitch and constant pitch helical style inducers for use over the full flow rate range taken as 35% to 130% of the pump BEP. Results indicate the combined centrifugal impeller with a variable pitch inducer tends to have lower NPSHr3 at BEP and below the pump BEP flow rate, but the constant pitch inducer can have superior performance near the pump maximum flow rate.

Adding an expansive agent to increase the toughness of steel fibre reinforced concrete

2019 ◽  
Vol 26 (4) ◽  
pp. 197-208
Author(s):  
Leo Gu Li ◽  
Albert Kwok Hung Kwan
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
The Other ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Compressive Properties ◽  
Shrinkage Cracking ◽  
Steel Fibre Reinforced Concrete ◽  
Expansive Agent ◽  
Concrete Matrix

Previous research studies have indicated that using fibres to improve crack resistance and applying expansive agent (EA) to compensate shrinkage are both effective methods to mitigate shrinkage cracking of concrete, and the additions of both fibres and EA can enhance the other performance attributes of concrete. In this study, an EA was added to fibre reinforced concrete (FRC) to produce concrete mixes with various water/binder (W/B) ratios, steel fibre (SF) contents and EA contents for testing of their workability and compressive properties. The test results showed that adding EA would slightly increase the superplasticiser (SP) demand and decrease the compressive strength, Young’s modulus and Poisson’s ratio, but significantly improve the toughness and specific toughness of the steel FRC produced. Such improvement in toughness may be attributed to the pre-stress of the concrete matrix and the confinement effect of the SFs due to the expansion of the concrete and the restraint of the SFs against such expansion.

AFRICAN WOMEN AND FORBIDDEN GROUNDS: FEMALE SEXUALITY AND SELF-DETERMINATION IN AFRICAN LITERATURE

Imbizo ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 40-54
Author(s):  
Oyeh O. Otu
Keyword(s):  
Female Sexuality ◽  
Sense Of Self ◽  
African Literature ◽  
The Other ◽  
Self Determination ◽  
African Women ◽  
The Core ◽  
The Many ◽  
The One ◽  
Sexual Repression

This article examines how female conditioning and sexual repression affect the woman’s sense of self, womanhood, identity and her place in society. It argues that the woman’s body is at the core of the many sites of gender struggles/ politics. Accordingly, the woman’s body must be decolonised for her to attain true emancipation. On the one hand, this study identifies the grave consequences of sexual repression, how it robs women of their freedom to choose whom to love or marry, the freedom to seek legal redress against sexual abuse and terror, and how it hinders their quest for self-determination. On the other hand, it underscores the need to give women sexual freedom that must be respected and enforced by law for the overall good of society.

The development of body and organ shape

BMC Zoology ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ansa E. Cobham ◽  
Christen K. Mirth
Keyword(s):  
Relative Position ◽  
Body Shape ◽  
Single Cells ◽  
The Other ◽  
Geometric Features ◽  
Main Text ◽  
Size Characterization ◽  
Organ Shape ◽  
The Many

Abstract Background Organisms show an incredibly diverse array of body and organ shapes that are both unique to their taxon and important for adapting to their environment. Achieving these specific shapes involves coordinating the many processes that transform single cells into complex organs, and regulating their growth so that they can function within a fully-formed body. Main text Conceptually, body and organ shape can be separated in two categories, although in practice these categories need not be mutually exclusive. Body shape results from the extent to which organs, or parts of organs, grow relative to each other. The patterns of relative organ size are characterized using allometry. Organ shape, on the other hand, is defined as the geometric features of an organ’s component parts excluding its size. Characterization of organ shape is frequently described by the relative position of homologous features, known as landmarks, distributed throughout the organ. These descriptions fall into the domain of geometric morphometrics. Conclusion In this review, we discuss the methods of characterizing body and organ shape, the developmental programs thought to underlie each, highlight when and how the mechanisms regulating body and organ shape might overlap, and provide our perspective on future avenues of research.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

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