Application Of Water Ejector In Heating System

With the continuous expansion of the heating system,there are more and more rich pressure in the system that cannot be balanced by reducing the pipe diameter.In the traditional heating system,these rich pressure can only be dissipated by throttling.The introduction of the water ejector will effectively utilize this part of the energy,improve the efficiency of the heating system,and ultimately achieve the goal of energy saving and environmental protection.In this paper,the application performance of the water ejector in the heating system is studied from the following aspects.Firstly,according to the working principle and structural calculation of the water ejector,considering the working parameters of the application environment,the required water ejector structure under the determined operating parameters is analyzed.The key dimensions in the design process and the selection of important parameters are given.Secondly,according to the installation position of the water ejector in the heating system,the physical and mathematical models of the water ejector heating system is constructed.the model is solved and the operating characteristics are analyzed.Particularly,The effects of equal-scale flow regulation、primary flow regulation、and secondary flow regulation on system balance are analyzed.The results show that the installation of the water ejector enhances the mutual interference between the primary flow and the secondary flow.When the water ejector design flow ratio is 1,each 10%increase in the primary flow rate,the ejector head ratio will increase by 33%.Thirdly,the design experiment verified the analysis results of the mathematical model.The final results show that the experimental data are consistent with the trend of theoretical analysis.The equal-scale flow regulation of the water ejector heating system is basically achieved by changing the circulating pump frequency;the installation of the water ejector also enhances the mutual interference between the primary flow and the secondary flow.at the same time,the adjustment capability of valve is weakened.When the most unfavorable loop flow is reduced from 3t/h to 2t/h,The PFRCC of most unfavorable loop is about 10KPa/(m3/h)2more than the ordinary system,and the ejector head is increased by 43.8KPa.When the secondary unfavorable loop was reduced from 5t/h to 4t/h,The PFRCC of secondary unfavorable loop is about 0.7KPa/(m3/h)2 more than the ordinary system,while the ejector head was reduced by 10.6KPa.Finally,according to the simulation results of the water ejector used in the experiment,the structure of the water ejector is optimized from three aspects: the end of nozzle,the ejector chamber and the connection method of the diffuser.At the same time,the suitable installation position of the water ejector is analyzed in terms of the mixing ratio and the rich pressure in the heating system.