Research On The Low Temperature Pumping Performance Of Lubricating Grease In Fan Lubrication System

In order to reduce the consumption of resources and environmental pollution,the use of green energy has attracted more and more attention from many countries,and fan power generation is one of them.Most of the fan lubricating equipment adopts centralized lubrication system,but it is very difficult to convey lubricating grease in the lubrication pump due to the low temperature of the working environment.At the same time,the huge pressure drop of the lubricating grease in the flow process is the main problem affecting the pump ability.Especially in extremely cold conditions,the equipment will not be lubricated properly while the centralized lubricating system appears oil discharge or pipe rupture.Therefore,it is great significance to investigate the pump ability of lubricating grease in centralized lubricating system under low temperature.The aim of this paper is to investigate pump ability of lubricating grease at low temperatures.The rheological properties and the main influence factors of flow characteristic are investigated by both numerical simulation and experiments.In addition,the rheological properties and the main influence factors of flow characteristic are analyzed comparatively at low and room temperatures.The main research content is as follows:Firstly,the rheological behavior of the grease is studied using the rotational rheometer to get the variation law of yield stress and viscosity with temperature.Based on the flow curve of lubricating grease;the difference numerical calculations between Power-law constitutive equation,Bingham constitutive equation and Herschel-Bulkley constitutive equation are compared.The results shows that,three different constitutive equations fit the flow curves well,but the numerical calculation of pressure drop based on Herschel-Bulkley constitutive equation are better than else.Then,based on the rheological test method,the flow characteristics in terms of pressure drop,viscosity and velocity distributions are investigated using the CFD method to obtain the influence weight between factors.At the same time,the influence of yield stress and flow index on the velocity and viscosity distribution of lubricating grease in the pipeline under low temperature condition are analyzed.The results shows that,the temperature has the greatest influence on the flow-ability of lubricating grease in pipeline,and the viscosity and velocity distribution is uneven at low temperature;With the increase of yield stress,the velocity and viscosity distribution are decreasing and increasing respectively.However,with the increase of the popular index,the velocity and viscosity show a decreasing trend.Finally,the application of BP neural network and GRNN neural network in pressure drop prediction is compared pipe and the relationship between pipe diameter,flow rate,temperature and pressure loss is established in which the correctness of the neural network method is verified.Therefore,the complex calculation of the pressure drop in the pipe is solved to provide guidance for lubricating pump selection of.The results show that,GRNN neural network has higher accuracy in predicting the pressure loss of lubricating grease.