Optimal Design Study on the Radian and Length of the Guide Plates for the Pipeline Elbow

Pipeline elbows are extensively applied in the liquid-conveying piping system, which vibration and noise control are always difficult and critical. The structural style of the guide plates for the liquid-conveying pipe noise eliminating elbow is numerical calculated in this paper, then we find that the fluid liquidity in the liquid-conveying pipe elbow is improved very well by the cross-sectional bending radian and export length of the guide plates, and the two parameters are also optimal designed. The calculated results show that the total pressure difference in the liquid-conveying pipeline elbow decreases first and then increases with the cross-sectional bending radius of the guide plate increases; The total pressure difference decreases first and then increases with the export length of the guide plate increases; When the guide plates according to the gold ratio arrangement, the number, the cross-sectional bending radius and the length are 2, 200 mm and 40 mm respectively, we obtain the total pressure difference is 10707.87 Pa in the liquid-conveying pipeline elbow, comparing it to the result of the original program, it decreases 38.58%, so the internal flow field is improved better, the optimal design has a very obvious effect.

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Study on the Influence of Internal Flow Field in Pipeline Elbow by the Guide Plate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.142.130 ◽

2010 ◽

Vol 142 ◽

pp. 130-133

Author(s):

Lan Ying Wu ◽

Yan Lin Wang ◽

Zi Dong Wang ◽

Ming Wen Chen

Keyword(s):

Optimal Design ◽

Flow Field ◽

Pressure Difference ◽

Total Pressure ◽

Internal Flow ◽

Piping System ◽

Optimal Result ◽

Obvious Effect ◽

Guide Plate

The liquid-conveying elbow is an very important part in the piping system, in this paper, the internal flow field in the pipeline elbow is studied, its structure is optimized, and the guide characteristic is improved. The results show that the internal total pressure difference in the original elbow is 29506.27 Pa, the Max-velocity is 7.12 m/s, and the internal flow field is very uneven；The internal total pressure difference can be greatly reduced through setting up the guide plates appropriately, its internal total pressure difference decreases as the number of guide plates increases, the Max-velocity decreases first and then increases as the number increases; When the number is a constant, the optimal result of guide plate according to the gold ratio arrangement is superior to the equidistance ratio arrangement; When the export length of guide plate is 50 mm, the total pressure difference is 14942 Pa in the elbow, comparing it to the result of the original elbow, it decreases 49.26%, the optimal design has an very obvious effect.

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An Investigation Into the Effect of Pre-bending on the Tube Hydro-forging Technology

10.21203/rs.3.rs-1173419/v1 ◽

2021 ◽

Author(s):

Caiyuan Lin ◽

Guan-Nan Chu ◽

Lei Sun

Keyword(s):

Internal Pressure ◽

Pressure Difference ◽

Cold Work ◽

Hoop Strain ◽

Cross Sectional ◽

Advanced Method ◽

Double Curvature ◽

Straight Wall ◽

Bending Radius ◽

Tubular Component

Abstract Tube hydro-forging (THFG) combining with the pre-bending is an advanced method to manufacture the complex cross-sectional tubular component with curved axis. However, the effect of pre-bending on the subsequent THFG, especially on the critical internal pressure required to inhibit wrinkling, has not been clarified yet. Therefore, this paper makes a detailed study on it. At first, based on the energy method, the change rule between the critical internal pressure and the hoop strain was established when pre-bending was considered. Subsequently, the mechanics condition difference between single and double curvature differential segment during THFG was analyzed. Via the plastic theory, the distribution of hoop strain could be obtained. Mainly due to the uneven distribution of thickness and cold work-hardening caused by pre-bending, the maximum hoop strain at the outer straight-wall was greater than that at the inner straight-wall during THFG. Substituting the maximum hoop strain at the outer/inner straight-wall into the change rule, then their mathematical model of the critical internal pressure to restrain the wrinkling could be solved respectively. Finally, the critical internal pressure considering pre-bending was determined by that of outer straight-wall, and its value was always greater than the critical internal pressure without considering pre-bending under the same punch stroke. With the increase of bending radius, the critical internal pressure difference between considering and not considering pre-bending also increases. When the bending radius was 250 mm, the critical internal pressure difference was 33%, while it increased to 74% as the bending radius reduced to 100 mm, all of which were verified by experiment. The effect of friction coefficient on the critical internal pressure was also studied. In conclusion, this work provided a new and more accurate prediction model of critical internal pressure to guide practical production for when existing the pre-bending.

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Experimental Study on Residual Cross-Sectional Flattening of Thin-Walled Pipes Under Pure Plastic Bending

Journal of Pressure Vessel Technology ◽

10.1115/1.4044852 ◽

2019 ◽

Vol 141 (6) ◽

Author(s):

Ziqian Zhang

Keyword(s):

Cross Section ◽

Wall Thickness ◽

Residual Deformation ◽

Outer Diameter ◽

Cross Sectional ◽

Plastic Bending ◽

Thin Walled Pipe ◽

Bending Radius ◽

Thin Walled ◽

The Cross

Abstract Cross-sectional ovalization (ovalization) usually occurs when thin-walled pipe is subjected to large plastic bending. This paper is concerned with residual deformation of thin-walled pipe's cross section in a radial direction when external bending moment is removed. In order to clarify the fundamental ovalization characteristics, find out what factors influence the residual flattening (value of ovalization), the ovalization behavior is investigated experimentally. The experiments are carried out on 21 stainless steel specimens with different geometric parameters under different bending radii by means of a four-point pure bending device. The residual cross-sectional flattenings are monitored continuously by scanning the cross section periodically along the circumferential direction. From the experimental results, it is observed that the cross-sectional shape of the thin-walled pipe is not perfect standard ellipse, and the appearance of the maximum residual flattening is usually found in the direction normal to the neutral surface. It is also revealed the relationships between the residual flattening and the bending radius, the wall thickness, and the pipe outer diameter, i.e., the residual flattening increases as the bending radius and the wall thickness reduce, but it increases as the outer diameter increases. These results are expected to find their potential application in thin-walled pipe bending operation.

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Parametric Study on Fluid Dynamics of Pilot-Control Angle Globe Valve

Journal of Fluids Engineering ◽

10.1115/1.4040037 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 21

Author(s):

Jin-yuan Qian ◽

Zhi-xin Gao ◽

Bu-zhan Liu ◽

Zhi-jiang Jin

Keyword(s):

Energy Consumption ◽

Pressure Difference ◽

Orifice Diameter ◽

Piping System ◽

Cross Sectional ◽

Core Diameter ◽

Large Orifice ◽

Difference Calculation ◽

Globe Valve ◽

Pilot Valve

Globe valve is widely used in numerous industries, and its driving energy consumption accounts for high percentages of the whole piping system. In order to figure out novel globe valves with low energy consumption, the pilot control globe valve (PCGV) is proposed, which is made up of a main valve and a pilot valve. By the pressure difference of fluid itself, the opened/closed status of the main valve can be controlled by the pilot valve, which can save driving energy and shorten the response time. In order to fit PCGV in an angle displaced piping system, the pilot control angle globe valve (PCAGV) is developed. In this paper, with validated numerical methods, both steady and transient simulations focusing on the valve core diameter, the single/multi orifices, orifice diameters and their arrangements located on the valve core bottom are presented. The results show that the pressure difference increases with the increase of the valve core diameter and the decrease of the orifice diameter, and large orifice diameters (d > 12 mm) should be avoided in case the valve cannot be opened. As for the multi orifices, it can be treated as a single orifice which having similar cross-sectional area. Meanwhile, the opening time of the main valve also increases with the increase of the valve core diameter correspondingly. Besides, a fitting formula of pressure difference calculation depending on the inlet velocity and the valve core diameter is obtained, which is a power–law relationship.

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Development of Double Suction Volute Pump for High Efficiency

Volume 1B, Symposia: Fluid Machinery; Fluid Power; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Fundamental Issues and Perspectives in Fluid Mechanics ◽

10.1115/fedsm2013-16345 ◽

2013 ◽

Cited By ~ 2

Author(s):

Katsutoshi Kobayashi ◽

Isao Hagiya ◽

Hideki Akiniwa ◽

Hiroaki Yoda ◽

Daijirou Senba

Keyword(s):

Pressure Loss ◽

Total Pressure ◽

High Efficiency ◽

Flow Path ◽

Total Pressure Loss ◽

Design Parameters ◽

Pump Efficiency ◽

Cross Sectional ◽

Swirl Velocity ◽

The Cross

The double suction volute pump consists of three components: a double suction flow path in upstream, an impeller with five blades, and a double volute flow path in downstream. The double suction was designed to improve a flow on the inlet surface of impeller. A significantly high pre-swirl velocity and low pre-swirl velocity were observed in original double suction, however its high pre-swirl velocity was slowed down and its low pre-swirl velocity was speeded up in designed double suction. As a result, the designed double suction had a more uniform velocity distribution on the inlet surface of impeller. The impeller had twenty design parameters and those parameters were optimized by genetic algorithm (GA) to improve the impeller efficiency. A high total pressure loss was observed on the outlet surface of impeller and near the shroud wall of impeller meridian surface. On the other hand, its total pressure loss was decreased in optimized impeller, and the impeller efficiency increased by +0.7[%]. The cross-sectional surfaces, which were defined on a main streamwise curve of double volute, were designed to decrease a total pressure loss occurring inside double volute. In designed double volute, a secondary vortex on the cross-sectional surface was suppressed and a high circumferential velocity was decreased near the tongue and front edge of partition wall. As a result, the total pressure loss was decreased inside designed double volute. The hydraulic pump performance for designed pump, which consisted of the designed double suction, optimized impeller and designed double volute, was predicted by numerical simulation. Efficiencies in double suction, impeller and double volute were increased by 0.6[%], 0.4[%] and 1.1[%] respectively and the total improvement of pump efficiency was 1.9[%]. The designed pump was manufactured and its hydraulic performance was measured by experiment. The numerical results of pump efficiency agreed well with experimental ones. The efficiency of designed pump increased by 2.0[%] compared with that of original pump in experiment.

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On the cross-sectional shape of the cellulose crystallites in the tunicate Halocynthia papillosa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160388 ◽

1990 ◽

Vol 48 (3) ◽

pp. 566-567

Author(s):

J.-F. Revol ◽

Y. Van Daele ◽

F. Gaill

Keyword(s):

Contrast Imaging ◽

Animal Kingdom ◽

Bright Field ◽

Field Mode ◽

Cross Sectional ◽

Ultrathin Sections ◽

The Cross ◽

Sectional Shape ◽

Valonia Ventricosa ◽

C Nmr

The only form of cellulose which could unequivocally be ascribed to the animal kingdom is the tunicin that occurs in the tests of the tunicates. Recently, high-resolution solid-state l3C NMR revealed that tunicin belongs to the Iβ form of cellulose as opposed to the Iα form found in Valonia and bacterial celluloses. The high perfection of the tunicin crystallites led us to study its crosssectional shape and to compare it with the shape of those in Valonia ventricosa (V.v.), the goal being to relate the cross-section of cellulose crystallites with the two allomorphs Iα and Iβ.In the present work the source of tunicin was the test of the ascidian Halocvnthia papillosa (H.p.). Diffraction contrast imaging in the bright field mode was applied on ultrathin sections of the V.v. cell wall and H.p. test with cellulose crystallites perpendicular to the plane of the sections. The electron microscope, a Philips 400T, was operated at 120 kV in a low intensity beam condition.

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INTERARM SYSTOLIC BLOOD PRESSURE DIFFERENCE IS ASSOCIATED WITH A HIGH PREVALENCE OF CARDIO VASCULAR DISEASES- A CROSS-SECTIONAL STUDY IN POLICE WORKER

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v4i11.1524 ◽

2020 ◽

Vol 4 (11) ◽

Author(s):

Somesh Raju ◽

Rina Kumari ◽

Sunita Tiwari ◽

NS Verma

Keyword(s):

Blood Pressure ◽

Systolic Blood Pressure ◽

Blood Sugar ◽

Pressure Difference ◽

Systolic Pressure ◽

Working Environment ◽

Vascular Events ◽

Cross Sectional ◽

Blood Pressure Difference ◽

High Prevalence

Background: Interarm systolic blood pressure difference more than 10 mm of Hg is predictor of cardiovascular and metabolic risk. Despite of sufficient physical activity there is high prevalence of obesity in police personal because of stressful working environment. No studies have addressed the significance of interarm pressure difference among them. Therefore, the present study conducted to access the relation of interarm blood pressure difference with obesity in police personnel. Aims and Objective: To estimate the interarm pressure difference in police personal to see its association with their obesity. Material and Method: This cross-sectional observational study done on 245 police workers in PAC, Sitapur, India. Subjects having more than ten years of working experience were included in study. Anthropometric measurements of subject recorded by following standard protocol. Measurement of systolic pressure in both arm recorded simultaneously by mercury sphygmomanometer. Available data analyze and expressed in percentage, mean with SD and chi square test to see the significance of association. Results: According to anthropometric results of subjects 77.14 prcent subjects were having generalised obesity and 82.04 percent of subjects having abdominal obesity. 34.29 percent of subjects showed abnormally high (?10 mmHg) inter-arm systolic blood pressure difference. Both type of obesity showed positive association with blood sugar level but no association with interarm pressure difference. Conclusion: Interarm blood pressure difference is greater in individual having obesity or prolong duration of service. Such subjects are more susceptible to develop coronary artery disease or peripheral arterial disease in future. Early screening can help to detect the vascular events likely to occur in the future Keywords: Body mass index, Waist circumference, Interarm pressure difference, Random blood sugar

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