Experimental Investigation on Flow Characteristics of Hydrogen in Pipelines

2009 ◽  
Author(s):  
Jinyang Zheng ◽  
Honggang Chen ◽  
Ping Xu ◽  
Yongzhi Zhao ◽  
Lifang Zhang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
Technical Problems ◽  
Hydrogen Flow ◽  
Pressure Pipeline ◽  
Hydrogen Supply ◽  
High Pressure Pipeline ◽  
Different Characteristics ◽  
Supply Systems

The design of high pressure pipeline is one of key technical problems facing the realization of hydrogen refueling stations and fuel cell automobiles. Currently, hydrogen velocity restrictions in pipeline are considered in reference to natural gas, which leads to some difficulties in design of pipelines for hydrogen supply systems. Considering the different characteristics of hydrogen, this paper establishes an analytical model and carries out a series of experimental tests to investigate the flow characteristics of hydrogen in pipelines. The effects of the pressure in the pipeline on the hydrogen flow velocity and mass flow are studied, and the corresponding relationships are also obtained. The results may provide references for the design of hydrogen pipelines and the development of standards in hydrogen refueling stations and hydrogen supply systems.

Investigation on the drag effect of a rolling element confined in the cavity of a cylindrical roller bearing

2021 ◽  
pp. 135065012110260
Author(s):  
Wenjun Gao ◽  
Shuo Zhang ◽  
Xiaohang Li ◽  
Zhenxia Liu
Keyword(s):  
Open Space ◽  
Roller Bearing ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
Windward Side ◽  
Leeward Side ◽  
Drag Effect ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

In cylindrical roller bearings, the drag effect may be induced by the rolling element translating in a fluid environment of the bearing cavity. In this article, the computational fluid dynamics method and experimental tests are employed to analyse its flow characteristics and pressure distribution. The results indicate that the pressure difference between the windward side and the leeward side of the cylinder is raised in view of it blocking the flow field. Four whirl vortexes are formed in four outlets of two wedge-shaped areas between the front part of the cylindrical surface and adjacent walls for the cylinder of L/ D = 1.5 at Re = 4.5 × 103. Vortex shedding is found in the direction of cylinder axis at Re = 4.5 × 104. The relationship between drag coefficient and Reynolds number is illustrated, obviously higher than that of the two-dimensional cylinder in open space.

Improved Diffuser/Volute Combinations for Centrifugal Compressors

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Steglich ◽  
J. Kitzinger ◽  
J. R. Seume ◽  
R. A. Van den Braembussche ◽  
J. Prinsier
Keyword(s):  
Cross Sections ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Outer Radius ◽  
Inner Radius ◽  
Pressure Pipeline ◽  
The Cross ◽  
Improved Performance ◽  
High Pressure Pipeline ◽  
Original Configuration

Internal volutes have a constant outer radius, slightly larger than the diffuser exit radius, and the circumferential increase of the cross section is accommodated by a decrease of the inner radius. They allow the design of compact radial compressors and hence are very attractive for turbochargers and high-pressure pipeline compressors, where small housing diameters have a favorable impact on weight and cost. Internal volutes, however, have higher losses and lower pressure rise than external ones, in which the center of the cross sections is located at a larger radius than the diffuser exit. This paper focuses on the improvement of the internal volute performance by taking into account the interaction between the diffuser and the volute. Two alternative configurations with enhanced aerodynamic performance are presented. The first one features a novel, nonaxisymmetric diffuser̸internal volute combination. It demonstrates an increased pressure ratio and lower loss over most of the operating range at all rotational speeds compared with a symmetric diffuser̸internal volute combination. The circumferential pressure distortion at off design operation is slightly larger than in the original configuration with a concentric vaneless diffuser. Alternatively, a parallel-walled diffuser with low-solidity vanes and an internal volute allows a reduction of the unsteady load on the impeller and an improved performance, approaching that of a vaneless concentric diffuser with a large external volute.

Welding Stress Numerical Simulation and Analysis of High-Pressure Pipeline

2014 ◽  
Vol 912-914 ◽  
pp. 890-894
Author(s):  
Lei Zhang ◽  
Jin Zhou Zhang ◽  
Xiao Ming Li
Keyword(s):  
High Pressure ◽  
Welding Process ◽  
Source Model ◽  
Heat Source Model ◽  
Welding Stress ◽  
Welding Temperature ◽  
Welding Arc ◽  
Pressure Pipeline ◽  
Pipeline Welding ◽  
High Pressure Pipeline

Welded stress has an important impact on quality and life of of high-pressure pipeline. Based on pipeline material performance, considered welding arc force and its mining action, selected double ellipsoidal heat source model, simulated welding process of of high-pressure pipeline, analysised welding temperature field and stress field, determined the distribution disciplines of welding stress, provides useful help on exploring the disciplines of pipeline welding.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

Characteristics of Miniature Short-Tube Orifice Flows

1989 ◽  
Vol 203 (5) ◽  
pp. 351-358 ◽  
Author(s):  
T A Fox ◽  
J Stark
Keyword(s):  
Experimental Investigation ◽  
Critical Pressure ◽  
Fuel Injection ◽  
Flow Characteristics ◽  
Head Loss ◽  
Differential Pressure ◽  
Pressure Differential ◽  
Contraction Parameter ◽  
Volumetric Discharge ◽  
Short Tube

This paper presents the results of an experimental investigation into the flow characteristics of miniature short-tube orifices of a type commonly used for fuel injection. From measurements of differential pressure and volumetric discharge it is shown that these devices are susceptible to a cavitation-induced instability phenomenon known as hydraulic flip. It was found that this instability is limited to orifices of length less than fourteen diameters and occurs at a critical pressure differential which varies as a function of the orifice l/d ratio and contraction parameter β. In addition, the performance of the device is examined in terms of the head loss characteristics and it is shown that the mechanisms associated with hydraulic flip have a significant effect on the efficiency of discharge.

Experimental investigation on flow characteristics in circular tube inserted with rotor-assembled strand using PIV

2019 ◽  
Vol 27 (1) ◽  
pp. 1-9
Author(s):  
Lichen He ◽  
Weimin Yang ◽  
Changfeng Guan ◽  
Hua Yan ◽  
Lin Zheng ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Circular Tube ◽  
Flow Characteristics
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