Rotational speed

About: Rotational speed is a research topic. Over the lifetime, 23327 publications have been published within this topic receiving 151696 citations. The topic is also known as: speed of revolution & revolution rate.

3D CFD Analysis of a Vertical Axis Wind Turbine

Abstract: To analyze the complex and unsteady aerodynamic flow associated with wind turbine functioning, computational fluid dynamics (CFD) is an attractive and powerful method. In this work, the influence of different numerical aspects on the accuracy of simulating a rotating wind turbine is studied. In particular, the effects of mesh size and structure, time step and rotational velocity have been taken into account for simulation of different wind turbine geometries. The applicative goal of this study is the comparison of the performance between a straight blade vertical axis wind turbine and a helical blade one. Analyses are carried out through the use of computational fluid dynamic ANSYS® Fluent® software, solving the Reynolds averaged Navier–Stokes (RANS) equations. At first, two-dimensional simulations are used in a preliminary setup of the numerical procedure and to compute approximated performance parameters, namely the torque, power, lift and drag coefficients. Then, three-dimensional simulations are carried out with the aim of an accurate determination of the differences in the complex aerodynamic flow associated with the straight and the helical blade turbines. Static and dynamic results are then reported for different values of rotational speed.

Numerical simulation of combined heat and mass transfer processes in a rotary dehumidifier

Abstract: A new finite-difference method is presented for simulating the combined heat and mass transfer processes that occur in a solid desiccant dehumidifier, which is the main component of a solid desiccant dehumidification and cooling system. The numerical method is of high-order accuracy, is numerically implicit, and is unconditionally stable. This method allows for more rapid simulation of the performance of desitcant-based dehumidification and cooling systems. Using the numerical method, the effect of the rotational speed on the performance of an adiabatic rotary dehumidifier was parametricaily studied, and the optimal rotational speed was determined by examining the outlet adsorption-side humidity profiles and the humidity wave fronts inside the desiccant dehumidifier.

High-speed machining of titanium alloys using the driven rotary tool

Abstract: Machining of titanium at high cutting speeds such as from 4 m/s to 8 m/s is very challenging. In this paper, a new generation of driven rotary lathe tool was developed for high-speed machining of a titanium alloy, Ti–6Al–4V. The rotary tool was designed and fabricated based on the requirements of compact structure, sufficient stiffness and minimal edge runout. Cylindrical turning experiments were conducted using the driven rotary tool (DRT) and a stationary cutting tool with the same insert, for comparison in the high-speed machining of Ti–6Al–4V. The results showed that the DRT can significantly increase tool life. Increase in tool life of more than 60 times was achieved under certain conditions. The effects of the rotational speed of the insert were also investigated experimentally. Cutting forces were found to decline slightly with increase of the rotational speed. Tool wear appears to increase with the rotational speed in a certain speed range.