| Venturi steam trap has the excellent characteristics of no moving parts,wide applicability and saving steam energy,plays a role in steam blocking and drainage in steam equipment,and has a simple structure and high reliability,so it is widely used in energy,chemical,agricultural production,pharmaceutical and other steam equipment.At present,industrial equipment is gradually developing to high power and large flow,and the performance requirements of traps are getting higher and higher,but the research and development of Venturi steam traps in China is mainly to transform foreign imported products,and there is less research on the internal flow mechanism of Venturi steam traps.In this paper,a new high-performance ENSAVE Venturi steam trap was developed,and the ENSAVE Venturi steam trap of DN15 was studied by combining numerical simulation method and experimental research,and the internal flow mechanism of Venturi steam trap was analyzed.The main research work and conclusions are as follows:1.Optimized design of ENSAVE Venturi steam trapThe existing Venturi steam trap in practical applications is summarized and analyzed,and its structure is improved according to a large number of literature and actual needs,and a new ENSAVE Venturi steam trap is designed.First of all,the two pipe structures contained in the newly developed ENSAVE Venturi steam trap adopt an inclined design to facilitate on-site installation,and the inclined design extends the length of the expansion section of the venturi tube,increases the working range of the venturi tube,realizes automatic hydrophobic vapor resistance,improves the safety factor,and reduces the leakage rate.Secondly,the valve body filter is optimized and a magnetic box is designed at the bottom of the filter to effectively prevent blockage.The design results show that the angle range of the suitable expansion section is 7～8°,the length of the expansion section is extended by about 30%,and the venturi inner part is changed from the previous vertical installation to the oblique installation,so that it meets the on-site installation requirements and casting process requirements on the basis of meeting the design requirements.2.Numerical simulation of thermodynamic cavitation phenomenon in Venturi tubeNumerical simulation methods were used to study the cavitation phenomenon inside the Venturi steam trap.Mesh them with a highly accurate hexahedral mesh.A Venturi steam trap simulation model was established by combining the Mixture model and the ZGB cavitation model,and the calculation results were compared with the experimental test data to prove the effectiveness and applicability of the model.The phase distribution,velocity distribution,pressure distribution and temperature distribution in Venturi under different venturi structural parameters and different working conditions are analyzed,and the effect of thermodynamic effects on the cavitation characteristics of venturi steam traps is further revealed.The results show that the higher the inlet temperature of the Venturi tube,the greater the temperature drop in the cavitation concentration area,and the temperature of the cavitation concentration area decreases rapidly,which reduces the pressure of the saturated steam,and the length of the cavitation concentration area becomes shorter,which further inhibits the development of cavitation.3.Performance test and on-site trial of the new Venturi steam trapThrough the valve test center test bench,the hot condensate displacement determination test of the Venturi steam trap is measured,and the displacement of the typical internal part(model P16)under different working conditions is measured,and the measured value is simulated into a characteristic curve.The external characteristics of the newly developed Venturi steam trap were tested through on-site trial,and the effect was good,which proved the applicability and feasibility of the new product,and provided the basis for the development of other models of venturi steam trap and the development of the selection software. |
