Diffuser Design And Stratification Performance Analysis Of Thermal Stratification Heat Storage Water Tank

As the energy crisis is increasingly serious,and a great amount of industrial waste heat is needed to be used.Therefore,a reasonable method should be put forward to utilize the low temperature industrial waste heat.The temperature stratification water tank using water as the medium stores the energy in the high temperature water for the use of scattered heat users,which not only solves the utilization of industrial waste heat,but also meets the demand for heat supply of scattered users.The horizontal temperature stratification water tank was selected for study in this paper,and the structure of diffuser and inlet velocity of water tank,which are the factors of temperature stratification during the water tank cooling process,were investigated.The effects of the two factors on temperature field and velocity field and the variations of thermocline thickness during the water tank cooling process were investigated by CFD simulation.In addition,according to the temperature fitting curve of final outlet flow,the water outlet efficiency is calculated when the water flow process is complete.In this paper,the study of the structure of the diffuser is divided into three schemes: 1)oval cross section,uniform 10 mm hole;2)circular section,uniform 10 mm hole;3)circular section,8mm and 10 mm hole evenly distributed.The study of the inlet flow rate of the tank is mainly 1.0m / s,1.5m / s and 2.0m / s three inlet flow rate.At the inlet flow rate u = 1.0 m / s,the combination of the circular diffuser cross section,10 mm and 8 mm perforations has the thinnest thickness of the diagonal layer,the time of 120 s is 125 mm,210 mm at 140 s;Inlet flow rate(Scheme 3),found that when the inlet flow rate of 1.5m / s,the thickness of the inclined layer is the thinnest.Finally,found that the outlet temperature was in accordance with the Boltzmann formula.Then according to the fitting formula,the discharging efficiency and the outlet temperature of each tank at resident time were calculated.And found that the outlet water temperature(335.96K)and the effluent efficiency(77.30%)of third scheme tank are the best in all nine schemes when the inlet flow rate is 1.5m / s.