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.

Inhomogeneities in silicon carbide distribution in stirred liquids—a water model study for synthesis of composites

Abstract: An experimental study was conducted on the mixing quality of two-phase slurries in the model SiC–water system using a gravimetric technique with a view to determining the influence of impeller geometry and baffles on the uniformity of distribution of SiC in the mixture. A three-blade paddle with different blade angles and a variable-pitch blade impeller (A-3) were used for stirring the mixture at various rotational speeds. The results show that SiC concentration variation during stirring in the absence of baffles was 7.5 vol.%, whereas in the presence of four vertical baffles the concentration variation was reduced to 2 vol.%. The power consumption for homogeneous mixing varied between 17.5 and 175 W vol.−1 depending upon the type of impeller and its rotational speed. A semi-empirical correlation for obtaining uniform mixing has been developed based on the Reynolds number, the power number and the Froude number for stirred SiC–water slurries. The results on inhomogeneity of silicon carbide in water concentration during mixing are in close agreement with the modeling studies by previous workers on the water–SiC system, and with limited experimental studies on the real molten aluminum–SiC system used to cast metal–matrix composites.

A method of balancing a container which rotates about an essentially horizontal axis

Abstract: According to a method of balancing a container (10) which is rotating about an essentially horizontal axis, preferably a washing machine drum, the container is provided with cavities (15) evenly distributed along the periphery thereof and having openings (20) via which selectively liquid can be introduced in the respective cavity. A sensor (24) is provided for sensing vibrations caused by the rotation of the container and for emitting an electrical signal the magnitude of which is a measure of the magnitude of the vibrations. The container (10) is brought to rotate at a first rotational speed and the sensor signal is read. A predetermined amount of liquid is introduced in a randomly selected cavity (15) along the periphery of the drum. The sensor signal is again read and the value is compared with the preceding sensed value, wherein if the value is lower than the preceding one a new dose of the predetermined amount is introduced in the selected cavity while if the value is equal to or greater than the preceding one the predetermined amount is introduced in the immediate following cavity along the periphery. The described sequence is repeated until the sensor signal is lower than a predetermined, permissible value at which the container is brought to rotate at a second rotational speed, higher than the first one. The sequence described is repeated for different rotational speeds until the desired rotational speed has been reached and the sensor signal is lower than the predetermined value.