STUDY ON PRESSURE RESPONSE OF EJECTOR VACUUM CIRCUIT
Keywords:
ejector vacuum circuit, flow-rate characteristics, pressure responseAbstract
In the pneumatic vacuum systems that usually consist of air powered ejector, chamber, and resistance, the pressure response of the vacuum circuit is critical to the systematic strategic planning. This paper analyzes each component of the vacuum circuit and their effects on pressure response. Firstly, a model is proposed to calculate the pressure change by using the air status equation and ejector flow-rate characteristics. For the tested ejectors with linear flow-rate characteristics, the dynamic pressure responses are a first-order system under the isothermal condition without resistance. The proposed model has been proven experimentally to be valid and it can be used in the simulation of pressure response. Secondly, the effect of resistance inserted between ejector and chamber is analyzed by combining the flow-rate characteristics of the ejector and the resistance. The further dimensionless treatment is made by introducing a new parameter Gr* that indicates the effect of the resistance. Finally, the effects of temperature changes on pressure responses are studied on the basis of experimental data. The pressure response is faster in the non-isothermal chamber at the beginning of vacuum generation than that in isothermal chamber but it takes a long time to reach final vacuum degree.
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References
Chunnanond, K. and Aphornratana, S. 2004. Ejectors:
Applications in Refrigeration Technology.
Renewable and Sustainable Energy Reviews, Vol.
(2), pp. 129 - 155.
Dorin, P., Sorin, V., Adrian, M., Florin, M. and
Livia, P. 2006. Telematics Applications for a Body
Feed-positioning Station. Proceedings of the 6th
WSEAS International Conference on Distance
Learning and Web Engineering, Lisbon, Portugal,
pp. 38 - 43.
Fane, S. and Schlunke, A. 2008. Opportunities for
More Efficient Toilets in Australia -How Low CanWe Go? 3rd National Water Efficiency Conference,
pp. 1 - 10.
Gao, F., Zhou, J. X. and Li, M. 2010. Numerical
Simulation of Performance of Air-jet Vacuum
Pump for Coach Toilet. Zhenkong, Vol. 47(5), pp.
- 67. (In Chinese)
Guo, W. Q., Pu, R. P. and Han X. J. et al. 2003. The
analysis research of the aspirating mechanism and
function of vacuum generator. Zhenkong, Vol.
(6), pp. 54 - 56. (In Chinese)
Han, B. J., Fujita, T., Kawashima, K. and Kagawa,
T. 2001. Influence of Pressure Condition Change on
the Flow-rate characteristics of Pneumatic Valve.
Journal of the Japan Hydraulics and Pneumatics
Society, Vol. 32(6), pp. 143 - 149
Huang, B. J., Chang, J. M., Wang, C. P. and
Petrenko, V. A. 1999. A 1-D Analysis of Ejector
Performance. International Journal of Refrigeration,
Vol. 22(5), pp. 354 - 364.
ISO6358. 1989. Pneumatic Fluid Power-Components
Using Compressible Fluids-Determination of
Flow-rate Characteristics.
Kagawa, T. 1985. Heat Transfer Effects on the Frequency
Response of a Pneumatic Nozzle Flapper.
ASME. Journal of Dynamic Systems, Measurement,
and Control, Vol. 107, pp. 332 - 336.
Kagawa, T. 2002. Influence of Air Temperature
Change on Equilibrium Velocity of Pneumatic Cylinder.
ASME. Journal of Dynamic Systems, Measurement
and Control, Vol. 124, 336 - 341.
Kawashima, K., Kagawa, T. and Fujita, T. 2000.
Instantaneous Flow Rate Measurement of Ideal
Gases. ASME. Journal of Dynamic System, Measurement
and Control, Vol. 122(1). pp. 174 - 178.
Keenan, J. H. and Neumann, E. P. 1950. An Investigation
of Ejector Design by Analysis and Experiment.
Journal of Applied Mechanics, Vol. 17, pp.
- 305.
Keskeny, J., Huba, A. and Muka, I. 2006. High Elastic
Bionic Based Robot and Gripper. 3rd International
Conference on Mechatronics, pp. 236 - 241.
Li, M., Zhou, J. and Gao, F. 2010. Modeling Study on
Outdoor Vacuum Sewage System. Zhenkong,
Vol.47 (5), pp. 66 - 70. (In Chinese)
Li, Z. and Gajurel, D. R. 2001. Development of
Source Control Sanitation Systems in Germany.
Conference on Ecological sanitation, pp. 1 - 4.
Majumdar, S. R. 1996. Pneumatic systems: principles
and maintenance. McGraw-Hill Publishing Company
LTD.
Otis, D. R. 1970. Thermal Damping in Gas-Filled
Composite Material during Impact Loading. ASME.
Journal of Applied Mechanics, Vol.37. pp. 38 - 43.
Singhal, G., Tyagi, R. K., Dawar, A. L. and Subbarao,
P. M. V. 2010. Pressure Recovery Studieson a Supersonic Coil with Central Ejector Configuration.
Optics & Laser Technology, Vol. 42, pp.
- 1153.
Zhang, H., Zhang, J., Zong, G., Wang, W., and Liu,
R. 2006. “Sky Cleaner 3-A Real Pneumatic Climbing
Robot for Glass-Wall Cleaning” IEEE Robotic
& Automation Magazine, Vol. 13(1), pp. 32 - 41.
Zhang, H., Wang, W. and Zhang, J. 2009. A Novel
Passive Adhesion Principle and Application for an
Inspired Climbing Caterpillar Robot. IEEE International
Conference on Mechatronics, pp. 1 - 6.
Zheng, X. R., Zhang X. and Zhao Z. F. et al. 2005.
Relationship Between Structure Parameter and Performance
Parameter of Vacuum Ejector. Zhenkong,
Vol. 42(5), pp. 13 - 16. (In Chinese)