Authors:M. Zheng, L. Zhang, H. P. Teng, J. Hu, and M. L. Hu
In the present paper, CFD simulation is used to perform the numerical calculation of behaviours of multi-blade drag typed VAWT. The sliding grid technology, FLUENT software and PISO algorithm are involved. By taking wind power efficiency Cp as the goal function, the optimal situations of multi-blade drag typed VAWT with 4 and 6 blades are conducted by CFD simulation. In this investigation, the variable parameters include the rotation rate of wind-mill ω, the blade installation angle θ and the blade width d. The results show that: the optimal working conditions for the 4-blade wind mill at the inlet wind speed 8 m/s are ω = 18 r/ min, θ = 28°, and d = 0.83 m, which induces an optimal wind power efficiency rate Cp = 27.127%; the optimal working conditions for the 6-blade wind mill at the inlet wind speed 8 m/s are ω = 18 r/min, θ = 27°, and d = 0.67 m, which leads to an optimal wind power efficiency rate Cp = 30.404%.
Authors:Ferenc Ender, Diána Weiser, Botond Nagy, Csaba László Bencze, Csaba Paizs, Péter Pálovics, and László Poppe
Biotransformation of l-phenylalanine (l-1a) and five unnatural substrates (rac-1b–f) by phenylalanine ammonia-lyase (PAL) was investigated in a novel microfluidic device (Magne-Chip) that comprises microliter volume reaction cells filled with PAL-coated magnetic nanoparticles (MNPs). Experiments proved the excellent reproducibility of enzymecatalyzed biotransformation in the chip and the excellent reusability of the enzyme layer during 14 h continuous measurement (>98% over 7 repetitive measurements with l-1a). The platform also enabled fully automatic multiparameter measurements with a single biocatalyst loading of about 1 mg PAL-MNP. Computational fluid dynamics (CFD) calculations were used to study the flow field in the chambers and the effect of unintended bubble formation. Optimal flow rate for l-1a reaction and specific activities for rac-1b–f under these conditions were determined.
Authors:Viktor Misuk, Andreas Mai, Yuning Zhao, Julian Heinrich, Daniel Rauber, Konstantinos Giannopoulos, and Holger Löwe
Fast mixing is essential for many microfluidic applications, especially for flow at low Reynolds numbers. A capillary tube-in-tube coaxial flow setup in combination with a glass microreactor was used to produce immiscible multiphase segments. These double emulsion segments are composed of an organic solvent as the shell (outer) phase and a completely fluorinated liquid (Fluorinert® FC-40) as the core (inner) phase. Due to the higher density of the core droplets, they are responsive to changing their position to the force of gravity (g-force). By gently shaking or jiggling the reactor, the core drop flows very fast in the direction of the g-field without leaving the shell organic phase segment. Furthermore, by shaking or jiggling the reactor, the inner droplet moves along the phase boundary of the shell segment and continuous phase. Computational fluid dynamics (CFD) calculations show an enhancement of the internal circulations, i.e., causing an exceptional mixing inside of the shell segment. For reactions which are limited by mass transfer, where the conversion significantly increases with improved mixing, these recirculation zones are decisive because they also accelerate the mixing process. With a common phase-transfer catalytic (PTC) etherification of phenol with dimethyl sulphate, a remarkable increase of yield (85% gas chromatography [GC]) could be achieved by applying active mixing within a segment in continuous flow.
Authors:Barhm Mohamad, Jalics Karoly, Andrei Zelentsov, and Salah Amroune
] were used to determine parameters of gas flow and heat transfer into the boundary layer. References [ 11–13 ] emphasized that this mathematical model is typical for CFDcalculations of processes in piston engines. The effect of flow noise generated by