scholarly journals High-Fidelity CFD Simulations of Microfluidic Devices

Author(s):  
M.M. Athavale ◽  
A.J. Przekwas
2021 ◽  
Vol 4 (398) ◽  
pp. 15-23
Author(s):  
Zhang Qingshan ◽  
◽  
Chen Weimin ◽  
Du Yunlong ◽  
Dong Guoxiang ◽  
...  

A comparison between towing tank testing and full-scale CFD simulations is presented at three different target speeds. For the current self-propulsion simulation, the self-propulsion point was obtained using polynomial interpolation. The studies of boundary layer thickness, a basic grid uncertainty assessment and verification were performed to give some confidence of grid application to current self-propulsion simulation. All simulations are performed using a commercial CFD software STAR-CCM+. It is concluded that with high-fidelity numerical methods, it’s possible to treat hull roughness and directly calculate full-scale flow characteristics, including the effects of the free surface, none-linearity, turbulence and the interaction between propeller, hull and the flow field.


2020 ◽  
Vol 105 (3) ◽  
pp. 699-713 ◽  
Author(s):  
Hadrien Calmet ◽  
Daniel Pastrana ◽  
Oriol Lehmkuhl ◽  
Takahisa Yamamoto ◽  
Yoshiki Kobayashi ◽  
...  

Author(s):  
Paul Tucker ◽  
Suresh Menon ◽  
Charles Merkle ◽  
Joseph Oefelein ◽  
Vigor Yang

Author(s):  
Christopher Doyle ◽  
William Dempster ◽  
Steven Taggart

Abstract In this paper, the validity of the commonly used quasi-steady design approach to pressure relief valves (PRV) is examined by comparing detailed steady state conditions of valve behavior directly with transient conditions. To achieve this, a PRV conforming to ASME VIII standards was modelled using the commercial computational fluid dynamics (CFD) package ANSYS FLUENT to account for transient fluid-structure interaction processes. Detailed steady state CFD simulations were conducted using quasi-steady assumptions and compared to high fidelity transient moving mesh simulations to allow the piston forces to be examined. The results indicated that noticeably different magnitudes can occur between steady state and transient simulations; highlighting the possibility of significant differences occurring between quasi steady designed valves and their ultimate performance. In this paper, a single operating condition is examined, using air at 10.3 barg, for a 5231BX refrigeration valve supplied by the Henry Group to highlight the main issues. Analysis has indicated that the differences in performance are generated by temporal, short lived vortices at the piston surface which influences the bulk flow features as the disc accelerates and decelerates; altering the net disc forces when compared to steady state conditions.


Author(s):  
Guoping Xia ◽  
Georgi Kalitzin ◽  
Jin Lee ◽  
Gorazd Medic ◽  
Om Sharma

Abstract Accurate prediction of thermal field in high pressure turbines is a critical aspect of aerodynamic and durability design. This is particularly true when the flow at turbine inlet exhibits large gradients in temperature, both radially and circumferentially. In other words, in the presence of hot streaks from the combustor. In the numerical study presented in this paper, coupled high-fidelity eddy-resolving simulations of a combustor and a turbine are used to study the differences in the temperature profile at the exit of the first vane and the heat flux on the first blade, resulting from different positioning, or clocking, between the combustor fuel nozzles and turbine vanes. The resolved unsteadiness and turbulence from the combustor impacts mixing and secondary flow in the high pressure turbine. Temperature profiles from both actual combustor CFD simulations, as well as and modulated profiles with more pronounced variation, or pattern factor, are used at the turbine inlet. A threshold of the pattern factor that brings the benefit of clocking is identified. Clocking positioning between the combustor and vanes was studied for the most benefit.


2011 ◽  
Vol 83 (13) ◽  
pp. 5073-5077 ◽  
Author(s):  
Yong Luo ◽  
Wei Sun ◽  
Chang Liu ◽  
Gufeng Wang ◽  
Ning Fang

2020 ◽  
Vol 124 (1277) ◽  
pp. 941-974
Author(s):  
T. Zhang ◽  
G.N. Barakos

ABSTRACTThis paper presents a survey of published works on ducted fans for aeronautical applications. Early and recent experiments on full- or model-scale ducted fans are reviewed. Theoretical studies, lower-order simulations and high-fidelity CFD simulations are also summarised. Test matrices of several experimental and numerical studies are compiled and discussed. The paper closes with a summary of challenges for future ducted fan research.


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