Study on Working Characteristics of Expansion Energy Used Booster

2011 ◽  
Author(s):  
Yan Shi ◽  
Maolin Cai
Keyword(s):  
Mathematical Model ◽  
High Pressure ◽  
Flow Characteristics ◽  
Air Pressure ◽  
Compressed Air ◽  
Output Pressure ◽  
Movement Characteristics ◽  
Output Flow ◽  
Expansion Energy ◽  
Future Work

Boosters are widely used to obtain high-pressure air. In order to obtain a higher output flow of high-pressure air, a new kind of booster is proposed, namely, the Expansion Energy Used booster (EEU booster). Output flow is improved by utilizing the expansion power of the compressed air to accelerate the piston’s movement. A mathematical model of the booster is constructed and analyzed to obtain the piston’s movement characteristics, variations of air pressure in the boosting and driving chamber as well as the characteristics of the output flow. Evaluation of simulation and experimental flow characteristics shows that the derived model corresponds well to experimental results. For a source and output air pressure of 0.6Mpa and 0.8MPa respectively, the output flow of the booster rises as the Convergent Pressure in the driving chamber increases. At a certain point, the output flow stabilizes and remains at a near constant. For an output pressure of 0.8MPa at the Optimum Work State, the output flow declines with a rise in the boosting ratio. This research lays the foundation for future work on the optimization of the EEU booster.

Dimensionless Study on Output Flow Characteristics of Expansion Energy Used Pneumatic Pressure Booster

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Yan Shi ◽  
Maolin Cai
Keyword(s):  
Mathematical Model ◽  
Flow Characteristics ◽  
Average Output ◽  
Pneumatic Pressure ◽  
Output Pressure ◽  
Output Flow ◽  
Expansion Energy ◽  
Set Up ◽  
Piston Stroke ◽  
The Mathematical Model

To obtain high-pressure gas, air-driven boosters are widely used. In this paper, a new pneumatic pressure booster (named expansion energy used booster, short for EEU booster), which makes use of the expansion power of compressed air in driving chambers is proposed. To set a foundation for the study on optimization of the booster, the basic mathematical model of working processes is set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression for modeling simulation. In this way, the dimensionless output flow characteristics of the booster can also be found. Through analysis, it can be seen that, first, the dimensionless output flow of the booster is mainly determined by the dimensionless Piston Stroke-set (the piston stroke, when the driving chambers stopped to charge air, is defined to be Piston Stroke-set), the dimensionless output pressure of the booster and the dimensionless area of the piston in the driving chambers, the study on optimization of the booster can be done based on the analysis of the influence of the three dimensionless parameters on the dimensionless average output flow and the efficiency. Lastly, the mathematical model is verified experimentally. This research can be referred to in the design of EEU boosters and the study on optimization of the EEU booster.

scholarly journals Study of Air Pressure and Velocity for Solution Blow Spinning of Polyvinylidene Fluoride Nanofibres

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1014
Author(s):  
Rasheed Atif ◽  
Madeleine Combrinck ◽  
Jibran Khaliq ◽  
James Martin ◽  
Ahmed H. Hassanin ◽  
...  
Keyword(s):  
Polymer Solution ◽  
Polyvinylidene Fluoride ◽  
Fibre Diameter ◽  
Flow Characteristics ◽  
Air Pressure ◽  
Compressed Air ◽  
Input Pressure ◽  
Solution Blow Spinning ◽  
Fibre Morphology ◽  
Operational Simplicity

Solution blow spinning (SBS) is gaining popularity for producing fibres for smart textiles and energy harvesting due to its operational simplicity and high throughput. The whole SBS process is significantly dependent on the characteristics of the attenuation force, i.e., compressed air. Although variation in the fibre morphology with varying air input pressure has been widely investigated, there is no available literature on the experimentally determined flow characteristics. Here, we have experimentally measured and calculated airflow parameters, namely, output air pressure and velocity in the nozzle wake at 12 different pressure values between 1 and 6 bar and 11 different positions (retracted 5 mm to 30 mm) along the centreline. The results obtained in this work will answer many critical questions about optimum protrusion length for the polymer solution syringe and approximate mean fibre diameter for polyvinylidene fluoride (PVDF) at given output air pressure and velocity. The highest output air pressure and velocity were achieved at a distance of 3–5 mm away from the nozzle wake and should be an ideal location for the apex of the polymer solution syringe. We achieved 250 nm PVDF fibres when output air pressure and velocity were 123 kPa and 387 m/s, respectively.

Forecast of COVID-19 Trend Following Countrywide Movement Control Order in Malaysia: SEIR Model Approach (Preprint)

2020 ◽  
Author(s):  
Aidalina Mahmud ◽  
Poh Ying Lim ◽  
Hayati Kadir Shahar
Keyword(s):  
Mathematical Model ◽  
Incidence Rate ◽  
Movement Control ◽  
Seir Model ◽  
Infection Incidence ◽  
Contact Rates ◽  
Exposed Population ◽  
Control Order ◽  
Future Work ◽  
Model Approach

BACKGROUND On March 18, 2020, the Malaysian government implemented Movement Control Order (MCO) to limit the contact rates among the population and infected individuals. OBJECTIVE The objective of this study was to forecast the trend of the COVID-19 epidemic in Malaysia in terms of its magnitude and duration. METHODS Data for this analysis was obtained from publicly available databases, from March 17 until March 27, 2020. By applying the Susceptible, Exposed, Infectious and Removed (SEIR) mathematical model and several predetermined assumptions, two analyses were carried out: without and with MCO implementation. RESULTS Without MCO, it is forecasted that it would take 18 days to reach the peak of infection incidence. The incidence rate would plateau at day 80 and end by day 94, with 43% of the exposed population infected. With the implementation of the MCO, it is forecasted that new cases of infection would peak at day 25, plateau at day 90 and end by day 100. At its peak, the infection could affect up to about 40% of the exposed population. CONCLUSIONS It is forecasted that the COVID-19 epidemic in Malaysia will subside soon after the mid-year of 2020. Although the implementation of MCO can flatten the epidemiological curve, it also prolongs the duration of the epidemic. The MCO can result in several unfavorable consequences in economic and psychosocial aspects. A future work of an exit plan for the MCO should also be devised and implemented gradually. The exit plan raises several timely issues of re-infection resurgence after MCO are lifted.

Pressure Changes Induced by Whole Body Acceleration Shocks

1991 ◽  
Vol 113 (1) ◽  
pp. 27-29 ◽  
Author(s):  
E. Belardinelli ◽  
M. Ursino ◽  
G. Fabbri ◽  
A. Cevese ◽  
F. Schena
Keyword(s):  
Mathematical Model ◽  
Carotid Artery ◽  
Normal Pressure ◽  
Compressed Air ◽  
Whole Body ◽  
Body Acceleration ◽  
Vascular Bed ◽  
Pressure Changes ◽  
The Mathematical Model

In the present paper pressure changes induced by sudden body acceleration are studied “in vivo” on the dog and compared to the results obtainable with a recently developed mathematical model. A dog was fixed to a movable table, which was accelerated by a compressed air piston for less than 1 s. Acceleration was varied by changing the air pressure in the piston. Pressure was measured during the experiment at different points along the vascular bed. However, only data obtained in the carotid artery and abdominal aorta are presented here. The results demonstrated that impulse body accelerations cause significant pressure peaks in the vessel examined (about + 25 mmHg in the carotid artery with body acceleration of g/2). Moreover, pressure changes are rapidly damped, with a time constant of about 0.1s. From the present results it may be concluded that, according to the prediction of the mathematical model, body accelerations such as those occurring in normal life can induce pressure changes well beyond the normal pressure value.

An experimental study on the flow characteristics during the leakage of high pressure CO2 pipelines

2019 ◽  
Vol 125 ◽  
pp. 92-101 ◽  
Author(s):  
Shuaiwei Gu ◽  
Yuxing Li ◽  
Lin Teng ◽  
Cailin Wang ◽  
Qihui Hu ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Flow Characteristics ◽  
High Pressure Co2

scholarly journals BACH FLOWS OF PRODUCT MANIFOLDS

2012 ◽  
Vol 09 (05) ◽  
pp. 1250039 ◽  
Author(s):  
SANJIT DAS ◽  
SAYAN KAR
Keyword(s):  
Dynamical System ◽  
Fixed Point ◽  
Ricci Flow ◽  
Flow Characteristics ◽  
Geometric Flow ◽  
Flow Equations ◽  
First Order ◽  
Bach Tensor ◽  
Point Condition ◽  
Future Work

We investigate various aspects of a geometric flow defined using the Bach tensor. First, using a well-known split of the Bach tensor components for (2, 2) unwarped product manifolds, we solve the Bach flow equations for typical examples of product manifolds like S2 × S2, R2 × S2. In addition, we obtain the fixed-point condition for general (2, 2) manifolds and solve it for a restricted case. Next, we consider warped manifolds. For Bach flows on a special class of asymmetrically warped 4-manifolds, we reduce the flow equations to a first-order dynamical system, which is solved exactly to find the flow characteristics. We compare our results for Bach flow with those for Ricci flow and discuss the differences qualitatively. Finally, we conclude by mentioning possible directions for future work.

Prediction of Surface Roughness in Compressed Air Jet Assisted High Speed End Milling of Silicon Using Diamond Coated Tools

2012 ◽  
Vol 576 ◽  
pp. 41-45
Author(s):  
A.K.M. Nurul Amin ◽  
M.A. Mahmud ◽  
M.D. Arif
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Surface Finish ◽  
High Speed ◽  
End Milling ◽  
Silicon Wafers ◽  
Compressed Air ◽  
Machining Parameters ◽  
High Quality ◽  
Ductile Mode

The majority of semiconductor devices are made up of silicon wafers. Manufacturing of high-quality silicon wafers includes numerous machining processes, including end milling. In order to end mill silicon to a nano-meteric surface finish, it is crucial to determine the effect of machining parameters, which influence the machining transition from brittle to ductile mode. Thus, this paper presents a novel experimental technique to study the effects of machining parameters in high speed end milling of silicon. The application of compressed air, in order to blow away the chips formed, is also investigated. The machining parameters’ ranges which facilitate the transition from brittle to ductile mode cutting as well as enable the attainment of high quality surface finish and integrity are identified. Mathematical model of the response parameter, the average surface roughness (Ra) is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered.

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