Pressure Loss Reduction in U-Bend Using the Adjoint Method

2017 ◽  
Vol 17 (17th International Conference) ◽  
pp. 1-15
Author(s):  
Ahmed Osama ◽  
Khairy Elsayed ◽  
Mohamed El-Telbany
Keyword(s):  
Pressure Loss ◽  
Adjoint Method ◽  
Loss Reduction

scholarly journals Pressure Loss Reduction in U-Bend Using the Adjoint Method

2017 ◽  
Vol 17 (AEROSPACE SCIENCES) ◽  
pp. 1-15
Author(s):  
Ahmed Osama ◽  
Khairy Elsayed ◽  
Mohamed El-Telbany
Keyword(s):  
Pressure Loss ◽  
Adjoint Method ◽  
Loss Reduction

Effects of Bio-Inspired Micro-Scale Surface Patterns on the Profile Losses in a Linear Cascade

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Qiang Liu ◽  
Shan Zhong ◽  
Lin Li
Keyword(s):  
Pressure Loss ◽  
Reynolds Numbers ◽  
Loss Reduction ◽  
Turning Angle ◽  
Low Reynolds Numbers ◽  
Linear Cascade ◽  
Micro Scale ◽  
Pressure Loss Coefficient ◽  
Surface Patterns ◽  
Scale Surface

Abstract In this paper, we investigated the effects of herringbone riblets, a type of bio-inspired micro-scale surface patterns, on pressure losses and flow turning angles in a linear cascade over a range of low Reynolds numbers from 0.50 × 105 to 1.50 × 105 and at three different incidence angles. Our experiments showed that despite their micro-scale size, herringbone riblets produced a significant reduction in pressure loss and a substantial increase in flow turning angle except at the low end of the Reynolds numbers tested. In comparison to the baseline case without riblets, the highest reduction in the zone-averaged pressure loss coefficient behind one flow passage was 36.4% which was accompanied by a 4.1 deg increase in the averaged turning angle. The loss reduction was caused by a decrease in γmax at α = −1 deg, a narrower wake zone at α = 9 deg and a mixture of both at α = 4 deg due to the suppression of flow separation on the blade suction surface. It was also noted that such a significant improvement was always accompanied by the appearance of a serrated wake structure in the contours of pressure loss coefficient in which the region with a higher loss reduction occurring directly behind the divergent region of herringbone riblets. The observed improvement in cascade performance was attributed to the secondary flow motion produced by herringbone riblets which energizes the boundary layer. Overall, this work has produced convincing experimental evidence that herringbone riblets could be potentially used as passive flow control devices for reducing flow separation in compressors at low Reynolds numbers.

Notch Arrangement Effects on Heat Transfer in a Channel With Cut-Fins

2007 ◽  
Author(s):  
Kazuya Tatsumi ◽  
Shintaro Matsuzaki ◽  
Kazuyoshi Nakabe
Keyword(s):  
Heat Transfer ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Main Flow ◽  
Loss Reduction ◽  
Transfer Coefficients ◽  
Piv Measurements ◽  
Heat Transfer Coefficients ◽  
Overall Performance ◽  
Spanwise Flow

The effects of the attack-angle of the fin notch array against the main flow and size of the clearance at the fin-tip on the heat transfer and pressure loss performances of a channel with cut-fins (parallel fins with square notches) mounted on the bottom wall were evaluated in the present article. Three-dimensional numerical simulations, PIV measurements and heat transfer experiments employing a modified single-blow method were conducted to discuss these characteristics. Larger pressure loss reduction was obtained by the cut-fins case compared with the plain-fins case (parallel fins without notches) under smaller clearance conditions, while smaller thermal resistance was achieved with larger clearance. A maximum peak, therefore, appeared in the overall performance in relation with the clearance size. Larger heat transfer coefficients were obtained with smaller attack-angles of the notch array in both experimental and numerical results, particularly under larger Reynolds number conditions. This was due to the spanwise flow generated in the area adjacent to the notch, by which renewal of the thermal boundary layer was effectively produced at the trailing edge of the notch.

scholarly journals Unconventional methods for pressure loss reduction in standard pipe elements

2018 ◽  
Vol 13 (2) ◽  
pp. 355-361
Author(s):  
Gábor Gönczi
Keyword(s):  
Energy Consumption ◽  
Numerical Modelling ◽  
Production Technology ◽  
Pressure Loss ◽  
Design Method ◽  
Loss Reduction ◽  
Energy Usage ◽  
Reduce Energy Consumption ◽  
Water Pumps ◽  
Unconventional Methods

Abstract Reduction of pressure at pump houses are the most feasible and most advantageous as the pipe design method that is used, is more than 200 years old and is based up on 19th century production technology. My research focuses on a general approach on improving and reducing the pressure loss of these pipe elements with the help of non-conventional methods, thus resulting in a lower and more optimal energy usage of pump houses. The problematic zones are identified with the help of numerical modelling, geometry changes can be made and tested the same method. The geometrical changes aiming at pressure loss reduction follow non-conventional ideas, form hemodynamic and other biomechanics sources. Pipes in the pump houses are designed, for more than 50 years of operation. Even a small pressure loss reduction with this new method will mean large amount of energy saving in total. The results show that 15%–60% of pressure loss reduction is feasible, according to the complexity of the geometry. Pressure loss reduction will reduce energy consumption of water pumps which will result in a more efficient water works operation.

scholarly journals Adjoint Shape Optimization coupled with LES-adapted RANS of a U-bend duct for pressure loss reduction

2021 ◽  
pp. 105057
Author(s):  
G. Alessi ◽  
T. Verstraete ◽  
L. Koloszar ◽  
B. Blocken ◽  
J.P.A.J. van Beeck
Keyword(s):  
Shape Optimization ◽  
Pressure Loss ◽  
Loss Reduction
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