| With the advancement of society and the development of science and technology,energy consumption in China has greatly increased.The popularization of air-conditioning systems has gradually increased the imbalance of electric power consumption during peak and valley periods,resulting in a large amount of energy waste.In order to realize peak shifting and valley filling of electric power and improve the energy utilization rate,cold storage technology has become a research hot spot in the field of energy conservation and environmental protection.As a new type of environment-friendly solid-liquid two phase fluid,ice slurry can be used to store and carry cooling capacity.It has a broad application prospect in the field of ice storage because of its excellent flow and heat transfer characteristics,and has been widely concerned by scholars.Different from single-phase flow,ice crystal particles will melt,break,and aggregate during the flow,leading to an ununified conclusion on the flow characteristics of ice slurry,which makes the application of ice slurry limited to some extent.The size of ice crystal particles is difficult to control during the preparation and the flow,which brings great difficulties to the basic theoretical research of ice slurry’s flow.Therefore,this paper focused on the effect of ice crystal particles’size on the flow characteristics of solid-liquid two phase flow like ice slurry,and carried out a simulation experiment.(1)In order to control the size of solid particles,polyethylene particles(density:922kg/m~3)were selected to replace ice crystal particles(density:920kg/m~3)to mimic the flow of ice slurry in horizontal circular pipes.Considering the size of solid particles,velocity,content of solid particles and pipe diameter,we designed and built an experimental platform for solid-liquid two phase flow like ice slurry to study the influence of different factors on the flow characteristics of slurry.(2)Combined with the transformation of flow pattern and the change of pressure drop.It can be found that when the size of solid particles is constant,increasing the content of solid particles or decreasing the diameter of conveying pipelines will increase the pressure drop of the mixed slurry,although it will help the mixed slurry tend to suspension flow.Reducing the size of the solid particles can improve the safety of the mixed slurry transportation and reduce the energy loss during the transportation process.Therefore,the size of the ice particles should be reduced as much as possible in the actual application of ice slurry.(3)Bingham and Power Law models were combined to analyze the rheological properties of the mixed slurry.The results show that this method can accurately obtain the yield stress of the mixed slurry.The content of solid particles and pipe diameter are the main factors affecting the rheological coefficient of slurry.The rheological coefficient will increase with the increase of solid particles’content,and decrease with the increase of pipe diameter.The effect of solid particles’size on rheological coefficient will gradually weaken with the increase of solid particles’content.And the rheological index of the mixed slurry is always greater than 1.The slurry behaves as a shear thickening fluid.(4)The flow resistance coefficient of the mixed slurry at different velocities were predicted respectively based on the Bingham model and Power Law model.The results show that the Power Law model can accurately predict the resistance coefficient of the mixed slurry at higher velocity,and the relative error between the predicted value and the experimental value can be controlled within 12%. |
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