Optimization of Piece-Wise Conical Nozzles: Theory and Application

2018 ◽  
Author(s):  
Karsten Hasselmann ◽  
Muhammad Aiman Bin Khamalrudin ◽  
Stefan aus der Wiesche ◽  
Eugeny Y. Kenig
Keyword(s):  
Flow Separation ◽  
Large Scale ◽  
Design Method ◽  
Elevated Pressure ◽  
Conical Nozzle ◽  
Measured Velocity ◽  
Pressure Distributions ◽  
Optimization Study ◽  
Large Scale Tests ◽  
Separation Number

In this contribution, an optimization study based on computational fluid dynamics (CFD) in combination with Stratford’s analytical separation criterion was developed for the design of piece-wise conical contraction zones. The occurrence of flow separation can be formally described by a newly introduced dimensionless separation number. In the optimization process, the risk of flow separation is reduced by minimizing this separation number. It was found that the optimized piece-wise conical nozzle shape did not correspond to a simple geometric approximation of the ideal polynomial shape. In fact, it was beneficial to reduce the deflection in the outlet region for a piece-wise conical nozzle stronger than for a conventional one. In order to validate the new design method, large-scale tests for different nozzle designs were conducted. The measured velocity profiles and wall pressure distributions agreed well with the CFD predictions. The new method was applied for designing the contraction zone of a new closed-loop organic vapor wind tunnel (CLOWT) working at elevated pressure levels.

Optimization of Piecewise Conical Nozzles: Theory and Application

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Karsten Hasselmann ◽  
Stefan aus der Wiesche ◽  
Eugeny Y. Kenig
Keyword(s):  
Flow Separation ◽  
Design Method ◽  
The Novel ◽  
Conical Nozzle ◽  
Measured Velocity ◽  
Separation Criterion ◽  
Pressure Distributions ◽  
Optimization Study ◽  
Computational Fluid Dynamics Cfd ◽  
Separation Number

An optimization study based on computational fluid dynamics (CFD) in combination with Stratford's analytical separation criterion was developed for the design of piecewise conical contraction zones and nozzles. The risk of flow separation was formally covered by a newly introduced dimensionless separation number. The use of this separation number can be interpreted as an adaption of Stratford's separation criterion to piecewise conical nozzles. In the nozzle design optimization process, the risk of flow separation was reduced by minimizing the separation number. It was found that the flow-optimized piecewise conical nozzle did not correspond to a direct geometric approximation of an ideal polynomial profile. In fact, it was beneficial to reduce the flow deflection in the outlet region for a piecewise conical nozzle to increase the nozzle performance. In order to validate the novel design method, extensive tests for different nozzle designs were conducted by means of wind tunnel tests. The measured velocity profiles and wall pressure distributions agreed well with the CFD predictions.

Staggered shear design of concrete beams: large-scale tests

1987 ◽  
Vol 14 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Lou M. Cerruti ◽  
Peter Marti
Keyword(s):  
Large Scale ◽  
Design Method ◽  
Shear Design ◽  
Diagonal Compression ◽  
Observed Behaviour ◽  
Potential Failure ◽  
Large Scale Tests ◽  
Compression Field ◽  
The Web ◽  
Key Words Beams

Two large-scale reinforced concrete I-beams were tested to failure. The principal difference between the two specimens was the angle of inclination selected for the diagonal compression field in the web. A 45° inclination was used for specimen CM1 whereas a 31° inclination was used for specimen CM2. The validity of the truss model approach used in design was confirmed by the observed behaviour of the specimens.Diagonal crushing limits given in the Canadian code CAN3-A23.3-M84 were found to be conservative. It is recommended to use these limits for uniformly stressed web regions when applying the staggering concept of shear design. For nonuniformly stressed regions it is proposed to investigate potential failure mechanisms assuming an effective compressive strength of the web concrete of [Formula: see text].Canadian code rules for determining longitudinal bar cutoff locations may be unconservative. To prevent the formation of premature collapse crack mechanisms, it is recommended to extend the bars beyond the theoretical cutoff points by at least one-half of the stirrup spacing. Key words: beams, concrete, deflection, deformation, design, failure, girders, limit design method, reinforcement, shear strength, shear tests, strains, stresses, tests.

scholarly journals Design of a Variable-Stiffness Compliant Skin for a Morphing Leading Edge

2021 ◽  
Vol 11 (7) ◽  
pp. 3165
Author(s):  
Zhigang Wang ◽  
Yu Yang
Keyword(s):  
Composite Laminate ◽  
Large Scale ◽  
Design Method ◽  
Leading Edge ◽  
Variable Stiffness ◽  
Manufacturing Constraints ◽  
Aircraft Wing ◽  
Noise Abatement ◽  
Civil Aircraft ◽  
Final Profile

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have difficulty in taking the manufacturing constraints or layup sequence into account during the optimization process. This paper proposes an innovative two-step design method for a variable-stiffness compliant skin of a morphing leading edge, which includes layup optimization and layup adjustment. The combination of these two steps can not only improve the deformation accuracy of the final profile of the compliant skin but also easily and effectively determine the layup sequence of the composite layup. With the design framework, an optimization model is created for a variable-stiffness compliant skin, and an adjustment method for its layups is presented. Finally, the deformed profiles between the directly optimized layups and the adjusted ones are compared to verify its morphing ability and accuracy. The final results demonstrate that the obtained deforming ability and accuracy are suitable for a large-scale aircraft wing.

scholarly journals Aerodynamic Inverse Design of Transonic Compressor Cascades with Stabilizing Elastic Surface Algorithm

2021 ◽  
Vol 11 (11) ◽  
pp. 4845
Author(s):  
Mohammad Hossein Noorsalehi ◽  
Mahdi Nili-Ahmadabadi ◽  
Seyed Hossein Nasrazadani ◽  
Kyung Chun Kim
Keyword(s):  
Design Method ◽  
Inverse Design ◽  
Normal Shock ◽  
Compressor Cascade ◽  
Elastic Surface ◽  
Transonic Compressor ◽  
Pressure Distributions ◽  
The Difference ◽  
Inverse Design Method ◽  
Transonic Cascade

The upgraded elastic surface algorithm (UESA) is a physical inverse design method that was recently developed for a compressor cascade with double-circular-arc blades. In this method, the blade walls are modeled as elastic Timoshenko beams that smoothly deform because of the difference between the target and current pressure distributions. Nevertheless, the UESA is completely unstable for a compressor cascade with an intense normal shock, which causes a divergence due to the high pressure difference near the shock and the displacement of shock during the geometry corrections. In this study, the UESA was stabilized for the inverse design of a compressor cascade with normal shock, with no geometrical filtration. In the new version of this method, a distribution for the elastic modulus along the Timoshenko beam was chosen to increase its stiffness near the normal shock and to control the high deformations and oscillations in this region. Furthermore, to prevent surface oscillations, nodes need to be constrained to move perpendicularly to the chord line. With these modifications, the instability and oscillation were removed through the shape modification process. Two design cases were examined to evaluate the method for a transonic cascade with normal shock. The method was also capable of finding a physical pressure distribution that was nearest to the target one.

scholarly journals Optimal Design of Novel Blade Profile for Savonius Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3484
Author(s):  
Tai-Lin Chang ◽  
Shun-Feng Tsai ◽  
Chun-Lung Chen
Keyword(s):  
Wind Energy ◽  
Drag Force ◽  
Wind Turbines ◽  
Rural Areas ◽  
Large Scale ◽  
Design Method ◽  
Angular Position ◽  
Vertical Axis ◽  
Blade Profile ◽  
Main Concept

Since the affirming of global warming, most wind energy projects have focused on the large-scale Horizontal Axis Wind Turbines (HAWTs). In recent years, the fast-growing wind energy sector and the demand for smarter grids have led to the use of Vertical Axis Wind Turbines (VAWTs) for decentralized energy generation systems, both in urban and remote rural areas. The goals of this study are to improve the Savonius-type VAWT’s efficiency and oscillation. The main concept is to redesign a Novel Blade profile using the Taguchi Robust Design Method and the ANSYS-Fluent simulation package. The convex contour of the blade faces against the wind, creating sufficient lift force and minimizing drag force; the concave contour faces up to the wind, improving or maintaining the drag force. The result is that the Novel Blade improves blade performance by 65% over the Savonius type at the best angular position. In addition, it decreases the oscillation and noise accordingly. This study achieved its two goals.

scholarly journals Steady flow separation patterns in a 45 degree junction

2000 ◽  
Vol 411 ◽  
pp. 1-38 ◽  
Author(s):  
C. ROSS ETHIER ◽  
SUJATA PRAKASH ◽  
DAVID A. STEINMAN ◽  
RICHARD L. LEASK ◽  
GREGORY G. COUCH ◽  
...  
Keyword(s):  
Flow Separation ◽  
Stokes Equations ◽  
Bypass Graft ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Measured Velocity ◽  
Curved Tube

Numerical and experimental techniques were used to study the physics of flow separation for steady internal flow in a 45° junction geometry, such as that observed between two pipes or between the downstream end of a bypass graft and an artery. The three-dimensional Navier–Stokes equations were solved using a validated finite element code, and complementary experiments were performed using the photochromic dye tracer technique. Inlet Reynolds numbers in the range 250 to 1650 were considered. An adaptive mesh refinement approach was adopted to ensure grid-independent solutions. Good agreement was observed between the numerical results and the experimentally measured velocity fields; however, the wall shear stress agreement was less satisfactory. Just distal to the ‘toe’ of the junction, axial flow separation was observed for all Reynolds numbers greater than 250. Further downstream (approximately 1.3 diameters from the toe), the axial flow again separated for Re [ges ] 450. The location and structure of axial flow separation in this geometry is controlled by secondary flows, which at sufficiently high Re create free stagnation points on the model symmetry plane. In fact, separation in this flow is best explained by a secondary flow boundary layer collision model, analogous to that proposed for flow in the entry region of a curved tube. Novel features of this flow include axial flow separation at modest Re (as compared to flow in a curved tube, where separation occurs only at much higher Re), and the existence and interaction of two distinct three-dimensional separation zones.

Compressible Flowfield Characteristics of Butterfly Valves

1989 ◽  
Vol 111 (4) ◽  
pp. 400-407 ◽  
Author(s):  
M. J. Morris ◽  
J. C. Dutton
Keyword(s):  
Flow Separation ◽  
Pressure Ratio ◽  
Disk Surface ◽  
Surface Flow ◽  
Operating Conditions ◽  
Local Geometry ◽  
Operating Pressure ◽  
Butterfly Valve ◽  
Pressure Distributions ◽  
Flow Separation And Reattachment

The results of an experimental investigation into the flowfield characteristics of butterfly valves under compressible flow operating conditions are reported. The experimental results include Schlieren and surface flow visualizations and flowfield static pressure distributions. Two valve disk shapes have been studied in a planar, two-dimensional test section: a generic biconvex circular arc profile and the midplane cross-section of a prototype butterfly valve. The valve disk angle and operating pressure ratio have also been varied in these experiments. The results demonstrate that under certain conditions of operation the butterfly valve flowfield can be extremely complex with oblique shock waves, expansion fans, and regions of flow separation and reattachment. In addition, the sensitivity of the valve disk surface pressure distributions to the local geometry near the leading and trailing edges and the relation of the aerodynamic torque to flow separation and reattachment on the disk are shown.

Structural topology optimization of bridge girders in cable supported bridges

2018 ◽  
Author(s):  
Mads Baandrup ◽  
Ole Sigmund ◽  
Niels Aage
Keyword(s):  
Topology Optimization ◽  
Large Scale ◽  
Design Method ◽  
Optimization Method ◽  
Bridge Girders ◽  
Structural Topology ◽  
Box Girders ◽  
Box Girder ◽  
Fine Mesh ◽  
Further Development

<p>This work applies a ultra large scale topology optimization method to study the optimal structure of bridge girders in cable supported bridges.</p><p>The current classic orthotropic box girder designs are limited in further development and optimiza­ tion, and suffer from substantial fatigue issues. A great disadvantage of the orthotropic girder is the loads being carried one direction at a time, thus creating stress hot spots and fatigue problems. Hence, a new design concept has the potential to solve many of the limitations in the current state­ of-the-art.</p><p>We present a design method based on ultra large scale topology optimization. The highly detailed structures and fine mesh-discretization permitted by ultra large scale topology optimization reveal new design features and previously unseen eff ects. The results demonstrate the potential of gener­ ating completely different design solutions for bridge girders in cable supported bridges, which dif­ fer significantly from the classic orthotropic box girders.</p><p>The overall goal of the presented work is to identify new and innovative, but at the same time con­ structible and economically reasonable, solutions tobe implemented into the design of future cable supported bridges.</p>

GEDUNG PERTANIAN HORTIKULTURA MASA DEPAN DI KAMPUNG MUKA

2021 ◽  
Vol 3 (1) ◽  
pp. 1005
Author(s):  
Bryan Wesley ◽  
Fermanto Lianto
Keyword(s):  
Large Scale ◽  
Design Method ◽  
Food Products ◽  
Food Assistance ◽  
Healthy People ◽  
Daily Activities ◽  
Government Assistance ◽  
Assistance Program ◽  
Government Program ◽  
Food Assistance Program

Because of the covid-19 virus pandemic in 2020, Indonesia is implementing large-scale social restrictions (PSBB) to protect healthy people from contracting the covid-19 virus. So most residents of Kampung Muka losing their jobs and unable to buy food for their daily needs. So they have to rely on the government’s non-cash food assistance program (BPNT). During the covid-19 pandemic occurred, the residents of Kampung Muka could not survive in their village and had to rely on government assistance to survive. The design method is the everydayness approach, by adding new daily activities in Kampung Muka, namely horticultural agriculture so that the residents can get a new source of livelihood. Also, horticultural agriculture is a source of food for residents during emergencies such as PSBB. Meanwhile, the commercial section is used as a place to sell food products and makes the view of horticultural agriculture a commercial attraction. Keywords: Commercial; Future; Government program; Horticultural agriculture Abstrak Dengan adanya pandemi virus Covid-19 pada tahun 2020, Indonesia memberlakukan pembatasan sosial berskala besar (PSBB) untuk melindungi orang yang sehat agar tidak tertular virus covid-19. Mengakibatkan kebanyakan warga Kampung Muka kehilangan pekerjaannya dan tidak dapat membeli pangan untuk kebutuhan hidup mereka sehari hari. Sehingga mereka harus bergantung pada program bantuan pangan non tunai (BPNT) pemerintah. Pada kondisi yang terjadi saat pandemi covid-19, warga Kampung Muka tidak dapat bertahan hidup di dalam kampung mereka sendiri dan harus bergantung pada bantuan pemerintah untuk bertahan hidup. Metode perancangan yang digunakan adalah pendekatan everydayness, dengan menambah aktivitas keseharian yang baru di Kampung Muka yaitu pertanian hortikultura, agar para warga mendapatkan sumber pencaharian yang baru. Selain itu, pertanian hortikultura juga sebagai sumber pangan para warga saat kondisi darurat seperti PSBB. Sedangkan bagian komersial, dimanfaatkan sebagai tempat untuk menjual hasil pangan dan menjadikan view pertanian hortikultura sebagai daya tarik komersial.

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