Experimental study on the effect of pressure and flow rate on cavitation in a poppet throttle valve

2019 ◽  
Vol 72 (5) ◽  
pp. 629-636
Author(s):  
Jian Zhang ◽  
Tingting Luo
Keyword(s):  
Flow Rate ◽  
Pressure Difference ◽  
High Speed ◽  
High Speed Camera ◽  
Experimental Conditions ◽  
Content Type ◽  
Experimental Support ◽  
Throttle Valve ◽  
Set Up

Purpose The purpose of this paper is to study the variation of cavitation scale with pressure and flow in poppet throttle valve, to obtain the cavitation scale under pressure and flow conditions and to provide experimental support for the research of suppressing throttle valve cavitation and cavitation theory. Design/methodology/approach A hydraulic cavitation platform was set up, a valve was manufactured with highly transparent PMMA material and a high-speed camera was used to observe the change in cavitation scale. Findings Through experiments, it is found that the pressure difference between inlet and outlet of throttle valve affects the cavitation scale, and the more the pressure difference is, the easier the cavitation will be formed. Under the condition of small pressure difference, the cavitation is not obvious and reducing the pressure difference can effectively suppress the cavitation; the flow rate also affects the cavitation scale, the smaller the flow rate, the more difficult the cavitation will be formed and the lower the flow rate, the more the cavitation will be suppressed. Research limitations/implications Because of the magnification factor of the high-speed camera lens, the morphology of smaller bubbles cannot be observed in this study, and the experimental conditions need to be improved in the follow-up study. Originality/value This study can provide experimental support for the study of throttle valve cavitation suppression methods and cavitation theory.

scholarly journals Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. F. Uddin ◽  
H. Mahfuz ◽  
S. Zainuddin ◽  
S. Jeelani
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
High Speed ◽  
Failure Modes ◽  
High Speed Camera ◽  
Test Results ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Set Up ◽  
Control Samples

We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscaleTiO2particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

scholarly journals Quasi 3D Nacelle Design to Simulate Crosswind Flows: Merits and Challenges

2019 ◽  
Vol 4 (3) ◽  
pp. 25 ◽  
Author(s):  
Alex Yeung ◽  
Nagabhushana Rao Vadlamani ◽  
Tom Hynes ◽  
Sumit Sarvankar
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Computational Modelling ◽  
Flow Characteristics ◽  
Attached Flow ◽  
Set Up ◽  
Engine Nacelle ◽  
Shape Changes

This paper studies the computational modelling of the flow separation over the engine nacelle lips under the off-design condition of significant crosswind. A numerical framework is set up to reproduce the general flow characteristics under crosswinds with increasing engine mass flow rate, which include: low-speed separation, attached flow and high speed shock-induced separation. A quasi-3D (Q3D) duct extraction method from the full 3D (F3D) simulations has been developed. Results obtained from the Q3D simulations are shown to largely reproduce the trends observed (isentropic Mach number variations and high-speed separation behaviour) in the 3D intake, substantially reducing the simulation time by a factor of 50. The agreement between the F3D and Q3D simulations is encouraging when the flow either fully attached or with modest levels of separation but degrades when the flow fully detaches. Results are shown to deviate beyond this limit since the captured streamtube shape (and hence the corresponding Q3D duct shape) changes with the mass flow rate. Interestingly, the drooped intake investigated in the current study is prone to earlier separation under crosswinds when compared to an axisymmetric intake. Implications of these results on the industrial nacelle lip design are also discussed.

Simulation and experimental study on lubrication of high-speed reducer of electric vehicle

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fuchun Jia ◽  
Yulong Lei ◽  
Xianghuan Liu ◽  
Yao Fu ◽  
Jianlong Hu
Keyword(s):  
Flow Field ◽  
Electric Vehicle ◽  
High Speed ◽  
Content Type ◽  
Speed Reducer ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Novel Method ◽  
Set Up ◽  
Volume Method

Purpose The lubrication of the high-speed reducer of an electric vehicle is investigated. The specific contents include visualization of the flow field inside reducer, lubrication evaluation of bearings and efficiency experiment. Design/methodology/approach The flow field inside reducer at five working conditions: straight, uphill, downhill, left lean and right lean is simulated by smoothed particle hydrodynamics (SPH). According to the instantaneous number of particles through bearings, the lubrication states of bearings are evaluated. The test platform is set up to measure the efficiency of the reducer. Findings The flow field inside the reducer is obtained, the lubrication of bearings needs to be improved, the efficiency of the electric vehicle reducer meets the requirement. Originality/value The SPH method is used to simulate lubrication instead of using the traditional grid-based finite volume method. A novel method to evaluate the lubrication of bearings is proposed. The method and conclusions can guide electric vehicle reducer design.

Determinants of authentic experiences

2016 ◽  
Vol 28 (10) ◽  
pp. 2247-2266 ◽  
Author(s):  
Jong-Hyeong Kim ◽  
SooCheong (Shawn) Jang
Keyword(s):  
Significant Interaction ◽  
Design Methodology ◽  
Experimental Conditions ◽  
Content Type ◽  
Native Culture ◽  
Ethnic Food ◽  
Food Experience ◽  
Korean Food ◽  
Practical Implications

Purpose This study aims to address a lack of studies on the attributes of ethnic restaurants that influence customers’ perceptions of authenticity. Particularly, this study extended Gilmore and Pine’s authenticity framework (is the offering true to itself and is the offering what it says it is) by incorporating a servicescape factor (i.e. employees). Design/methodology/approach This study used a 2 × 2 × 2 between-participants design which examined the effects of using an authentic sauce in a dish, advertising “authenticity” and employing staff from the native culture of the ethnic food on authentic experiences. Follow-up contact was made by phone and mail to assess their memory of ethnic Korean food tried in experimental conditions. Participants were asked how clearly and vividly they could recollect the food experience. Findings The results showed that all of the tested factors significantly influenced the subjects’ perceived authenticity of the food and recollection of the food experience. However, the authors did not find any significant interaction effects. Practical implications This study suggests factors that influence customers’ authentic experiences and memory. Thus, the findings provide important implications for delivering authentic and memorable experiences. Originality/value Previous researchers have emphasized the importance and urgency of providing authentic and memorable experiences. However, it is still unclear what specific attributes of ethnic restaurants influence individuals’ perceptions of authenticity and memory.

High-speed impact assessment for composite air inlet

2019 ◽  
Vol 11 (5) ◽  
pp. 723-736
Author(s):  
Radek Doubrava ◽  
Martin Oberthor ◽  
Petr Bělský ◽  
Jan Raška
Keyword(s):  
Numerical Simulation ◽  
Composite Structure ◽  
High Speed ◽  
Numerical Models ◽  
Impact Resistance ◽  
High Speed Camera ◽  
Content Type ◽  
High Speed Impact ◽  
Air Inlet ◽  
Final Design

Purpose The purpose of this paper is to describe the approach for the design of a jet engine composite air inlet for a new generation of jet trainer aircraft from the perspective of airworthiness requirements regarding high-speed impact resistance. Design/methodology/approach Validated numerical simulation was applied to flat test panels. The final design was optimised and verified by validated numerical simulation and verified by testing on a full-scale demonstrator. High-speed camera measurement and non-destructive testing (NDT) results were used for the verification of the numerical models. Findings The test results of flat test panels confirmed the high durability of the composite structure during inclined high-speed impact with a near-real jet inlet load boundary condition. Research limitations/implications Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology. Practical implications The application of flat test panels for the verification and tuning of numerical models allows optimised final design of the air inlet and reduces the risk of structural non-compliance during verification tests. Originality/value Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a real complex design and reduced calculation time.

Effect of depositing torch angle on the first layer of wire arc additive manufacture using cold metal transfer (CMT)

2019 ◽  
Vol 46 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Chuanchu Su ◽  
Xizhang Chen
Keyword(s):  
Weld Pool ◽  
High Speed ◽  
Additive Manufacture ◽  
High Speed Camera ◽  
Porosity Formation ◽  
Cold Metal Transfer ◽  
Content Type ◽  
Deposition Direction ◽  
Cold Metal ◽  
Torch Angle

Purpose This paper aims to mainly report the impact of torch angle on the dynamic behavior of the weld pool which is recorded and monitored in real time with the aid of a high-speed camera system. The influence of depositing torch angle on the fluctuation behavior of weld pool and the quality of weld formation are compared and analyzed. Design/methodology/approach The FANUC controlled robotic manufacturing system comprised a Fronius cold metal transfer (CMT) Advanced 4000R power source, FANUC robot, water cooling system, wire feeding system and a gas shielding system. An infrared laser was used to illuminate the weld pool for high-speed imaging at 1,000 frames per second with CR600X2 high-speed camera. The high-speed camera was set up a 35 ° angle with the deposition direction to investigate the weld pool flow patterns derived from high-speed video and the effect of torch angles on the first layer of wire additive manufacture-CMT. Findings The experimental results demonstrated that different torch angles significantly influence on the deposited morphology, porosity formation rate and weld pool flow. Originality/value With regard to the first layer of wire arc additive manufacture of aluminum alloys, the change of torch angle is critical. It is clear that different torch angles significantly influence on the weld morphology, porosity formation and weld pool flow. Furthermore, under different torch angles, the deposited beads will produce different defects. To get well deposited beads, 0-10° torch could be made away from the vertical position of the deposition direction, in which the formation of deposited beads were well and less porosity and other defects.

scholarly journals Monitoring the Capillary Jet Breakage by Vibration Using a Fast-Video Camera

2021 ◽  
Vol 11 (21) ◽  
pp. 10222
Author(s):  
Marcella Chalella Mazzocato ◽  
Sylvie Chevallier ◽  
Carmen S. Fávaro-Trindade ◽  
Denis Poncelet
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Video Camera ◽  
Solution Concentration ◽  
Low Flow ◽  
High Speed Camera ◽  
Optimum Conditions ◽  
Present Contribution ◽  
Simple Method ◽  
Alginate Solution

The production of beads by simple extrusion dropwise of an alginate solution in a calcium bath is a simple method. It may be done at room temperature without any toxic compound. However, simple extrusion drop by drop from a needle may result in large capsules and a low flow rate. The solution must be extruded as a jet to get a smaller size and higher flow rate, which breaks into droplets either by vibration or a cutting tool. The present contribution reports jet breakage observations into droplets under vibration by extruding an alginate solution varying some parameters during the study. The droplet formation was observed using a high-speed camera, and images were analyzed. The size, length before breakage, and droplet velocity were obtained by examining 50 droplets, and experiments were repeated three times. The high-speed camera allowed us to observe more precisely the capillary jet breakage. The study showed the importance of selecting a well-designed vibrating system, presented data while varying nozzle size, frequency, and flow rate to get optimum breakage keeping across all the same alginate solution. Further experiments would be interesting, modify the extruded solution concentration and composition, and find a precise criterion to identify optimum conditions.

Experimental and numerical analysis of a self-circulating oil bearing system for gear pumps

2018 ◽  
Vol 70 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Mo Jintao ◽  
Gu Chaohua ◽  
Pan Xiaohong ◽  
Zheng Shuiying ◽  
Ying Guangyao
Keyword(s):  
Flow Rate ◽  
Pressure Difference ◽  
The Self ◽  
Gear Pump ◽  
Moderate Pressure ◽  
Test Rig ◽  
Content Type ◽  
Oil Flow ◽  
Gear Pumps ◽  
Bearing System

Purpose For moderate pressure and high pressure gear pumps, the temperature failure problem of bearings is now of considerable concern because of their heavy loads. However, the compact structure and the efficiency consideration make it extremely difficult to improve the bearing cooling. A self-circulating oil bearing system is developed for gear pumps with self-lubricating bearings to solve this problem. The oil is aspirated in from the low pressure chamber of the gear pump and discharged to the same chamber by using the pressure difference in the journal bearing, thus achieving the self-circulation. Design/methodology/approach An experiment test rig has been built for the feasibility study. The oil flow rate under different speeds has been recorded. Furthermore, the temperatures of the bearings with or without the oil circulation have been compared. Additionally, the oil flow in the test rig has been simulated using computational fluid dynamics codes. Findings The experimental and numerical results agree well. The experimental results indicate that the oil flow rate increases approximately linearly with the speed and the bearing temperature can be lowered successfully. The calculation results indicate that the bearing load capacity is nearly the same. Both the experimental and numerical studies establish that the self-circulating oil bearing system works successfully. Originality value As far as the authors know, it is the first time to find that the self-circulation can be built using the pressure difference in the bearing oil film, and this principle can be applied in the cooling and lubrication of the gear pumps to solve the temperature failure problem.

Comparative Study on 2A70 Aluminum Alloy High-Speed Milling Cutting Force Model

2011 ◽  
Vol 188 ◽  
pp. 254-257
Author(s):  
Xue Hui Wang ◽  
Ming Jun Feng ◽  
Can Zhao
Keyword(s):  
Aluminum Alloy ◽  
Linear Model ◽  
Nonlinear Model ◽  
High Speed ◽  
Tool Path ◽  
Force Model ◽  
High Speed Milling ◽  
Set Up ◽  
Good Agreement

The mechanical properties of flat end mill is analyzed the high-speed milling, the linear model for milling force is established. And the 2A70 aluminum alloy four-factor four-level orthogonal milling tests are carried out, the nonlinear model of milling is set up by using regression analysis method. The comparative analysis is made between the linear model and nonlinear model, whose results show that the two models have good agreement on the value and trend of change, which is the basis of the follow-up tool path optimization, fault diagnosis and so on.

scholarly journals Pengaruh Diameter Piringan Katup Limbah Terhadap Tekanan Aliran Balik Dalam Pompa Hidram

Jurnal METTEK ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 98
Author(s):  
Kadek Bayu Laksana ◽  
Made Suarda ◽  
Ainul Ghurri
Keyword(s):  
Flow Pattern ◽  
Flow Rate ◽  
High Speed ◽  
Water Hammer ◽  
Back Pressure ◽  
High Speed Camera ◽  
Pressure Force ◽  
Drive Pipe ◽  
Disk Diameter ◽  
Movement Distance

Pompa hidram bekerja dengan memanfaatkan proses palu air. Terjadinya palu air akan mengakibatkan sebagian air menuju ke tabung udara dan sebagian lagi akan mengalami aliran balik pada pipa penggerak. Diameter piringan katup limbah mempengaruhi laju aliran dan gaya tekan di dalam badan pompa, sehingga akan mempengaruhi besarnya tekanan balik yang terjadi. Oleh sebab itu perlu dilakukan penelitian lebih lanjut mengenai pengaruh diameter piringan katup limbah terhadap tekanan aliran balik dalam pipa penggerak pompa hidram. Penelitian menggunakan variasi diameter piringan katup limbah 35 mm, 40 mm, 45 mm, 50 mm, dan 53 mm. Penelitian dilakukan dengan menggunakan kamera berkecepatan tinggi yaitu 960 fps, untuk merekam aliran balik yang sudah disemprotkan gliter sebelumnya. Sehingga didapatkan jarak pergerakan gliter untuk mendapat kecepatan dan pada akhirnya mendapat tekanan. Hasil dari penelitian menunjukkan diameter piringan katup limbah berpengaruh terhadap tekanan balik yang terjadi. Dimana head tekanan tertinggi terjadi pada diameter piringan katup limbah 40 mm sebesar 42.76 N/m2. Diikuti dengan debit pemompaan terbesar pada diameter piringan 42.88 mm sebesar 2.3 liter/menit. Selain tekanan, semakin besar diameter piringan katup limbah akan meningkatkan frekuensi dan efisiensi pompa hidram. Namun debit pembuangan menurun seiring bertambahnya diameter piringan. Hydram pump works by utilizing the water hammer process. Water hammer that take place some water flow into the air tube and some other will back into the drive pipe. The waste valve disk diameter affects the flow rate and the pressure force inside the pump body, so that it will affect the back pressure. Therefore it is necessary to conduct further research on the effect of the waste valve disk diameter to backflow pressure in the hydram pump drive pipe. The work used variations in diameter of 35 mm, 40 mm, 45 mm, 50 mm, and 53 mm. The flow pattern was recorded using a high-speed camera with 960 fps. The water was mixing with glitters. The glitter movement distance is obtained to get the speed and then its pressure. The results that show the diameter of the waste valve influences the back pressure. Finally the highest pressure is on the disk diameter 40 mm at 42.76 N/m2. Furthermore, the largest pumping debit was on a 42.88 mm disk diameter at 2.3 liters/minute. In addition, the larger valve disk diameter cause the higher frequency and efficiency. However, the waste debit decreases with increasing disk diameter.  

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