Papers by Keyword: Constant Flow

Abstract: Methylene blue value (MBV) is an effective index for detecting harmful clay in manufactured sand (MS) and it’s of great importance for quality control of MS concrete. In order to verify relationship between MBV and concrete properties and feasibility of using MBV to confine clay harmfulness, influences of MBV on fresh and hardened mortar properties were investigated under constant flow by means of adjusting water and water reducer content, respectively. The results indicate that water and water reducer demand and drying shrinkage increase while frost resistance decreases with increasing MBV. Meanwhile, compressive strength and permeability resistance decrease significantly with increasing MBV when water content is increased and they are not greatly negatively affected when W/C is held constant. Certain relationships can be established between MBV and mortar properties and adverse effect of clay is relatively limited when MBV is within 1.0g/kg.

Abstract: Large size hydrostatic bearing is the core component of heavy CNC equipment. The influence of pressure, heating and running time can reduce film thickness during operation. This will directly affect machining accuracy and operation reliability of the entire machine. Aiming at the problem of influence of rotational velocity on carrying capacity of heavy hydrostatic bearing, use finite volume method (FVM) to simulate gap film pressure field of heavy hydrostatic bearing with Constant Flow and study pressure field distribution law on the conditions of the different rotational velocity and same cavity depth, oil cavity area, then optimize oil cavity structure. Results show that, pressure field distribution law of the different rotational velocity is basically identical, but its carrying capacity is different. From the relation curve of the pressure and rotational velocity can be seen, because of the dynamic pressure of existence, along with the increase of rotational velocity, carrying capacity gradually. The study is of vital theoretical significance for the improvement of machining accuracy of numerical control machine and the entire CNC equipment and provides valuable theoretical basis for the design of hydrostatic guide rail in engineering practice.