تحلیل مکانیکال سیالات محاسباتی عملکرد کمپرسور پیچی

تحلیل مکانیکال سیالات محاسباتی عملکرد کمپرسور پیچی

CFD analysis of screw compressor performance

 

تقریبا 17 درصد برق تولیدی برای به حرکت درآوردن کمپرسورها مصرف می شود که تقریبا 80 درصد آنها که برای مصارف صنعتی استفاده می شود از نوع کمپرسورهای پیچی (Screw type) هستند. بهبود راندمان این ماشین ها می تواند به صرفه جویی در مصرف انرژی در سطح جهانی منجر شود.

پروفایل روتور و تفاوت در شکل پارامترهای اصلی طراحی هستند که بر روی عملکرد کمپرسورهای پیچی اثر می گذارد. این پارامترها که به سختی با چشم تشخیص داده می شوند اثر بسیاری بر روی مقدار دبی کمپرسور و توان مصرفی آن دارند.

روش های تولید مدرن این امکان را فراهم آورده است تا کمپرسورها با تلرانس های بسته تری ساخته شوند لذا محاسبات عددی سه بعدی برای بررسی دما و جریان سیال مورد نیاز می باشد تا بهترین عملکرد برای کمپرسور حاصل گردد.بنا براین نویسنده این مقاله برنامه رابط مستقل CAD-CFD را ایجاد کرده است تا شبکه عددی مورد نیاز برای این کار را فراهم آورد. این مقاله به این شرح این کار می پردازد.

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CFD analysis of screw compressor performance
حجم: 752 کیلوبایت

CFD Analysis of Off-design Centrifugal Compressor Operation and Performance

CFD Analysis of Off-design Centrifugal Compressor

Operation and Performance

 

 

Abstract

Mathematical modelling

This paper presents some of the results from a Master’s thesis research into the performance and operation of a centrifugal compressor at off-design operating conditions using advanced computational fluid dynamics (CFD) techniques. ANSYS CFX is the CFD solver used in this blind study to evaluate the ability of modern CFD software to predict the performance of centrifugal compressors operating at highly complex flows regimes.

The off-design cases considered included compressor operations at 60%, 70%, 80%, 90%, 100% and 105% of the on-design rotational speed. Speed lines were generated for each case and compared to experimental measurements. The predicted results were found to match very closely with the experimental measurements.

The flow within the centrifugal compressor stage was also examined by considering various performance parameters and making use of three-dimensional flow visualizations. This allowed for a better understanding of the fluid behavior within the centrifugal compressor.

Lastly, the benefits of unsteady (time accurate) simulation on centrifugal compressor performance predictions were investigated. The results obtained showed that unsteady simulations noticeably improve the accuracy of the compressor performance predictions.

 

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CFD Analysis of Off-design Centrifugal Compressor Operation and Performance
حجم: 1.32 مگابایت

 

Numerical Prediction Of Cavitation In Pumps

Numerical Prediction Of Cavitation In Pumps

 

ABSTRACT
With the increase in power per unit of volume for modem pumps, driven by manufacturing costs reduction, cavitation becomes more arid more the main limiting factor in pump design. The classical one-dimensional design rules applied for decades are no longer sufficient, and for this reason, there is a strong need for more accurate numerical tools to predict the cavitation behavior of pumps.
An original cavitation prediction method is presented and its results are compared to experimental data for five pumps of specific speeds from 15 to 125 (775 to 6500 US units). The numerical method introduced in this paper for the prediction of the cavitation development in pumps is a simplified version of a previously developed program successfully used in similar cases. Motivation for this simplification was to allow the program usage during the design process of suction impellers. The accuracy of this simplified method as well as its usage as a design tool is discussed. 

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Numerical Prediction Of Cavitation In Pumps
حجم: 687 کیلوبایت