Improved Design Of Horizontal Tube And Shell Condenser

As a common heat exchanger,horizontal shell and tube condenser plays an important role in the industrial field.Improving the heat exchanger efficiency of condenser has important practical significance for energy saving and consumption reduction.Aiming at the phenomenon of non-uniform distribution of flow in the shell side of a horizontal marine shell and tube condenser,an Impingement Plate is added below the shell inlet to enhance the heat transfer effect by changing the flow field distribution.The influence mechanism of the Impingement Plate on the flow and heat transfer characteristics of the shell side is discussed by the method of simulation analysis and experimental verification.First,the internal thermal resistance of the condenser is analyzed,and the thermal resistance of the condenser side is 75% of the total thermal resistance.According to the structural characteristics of the condenser,the initial Impingement Plate is designed.Based on the wall condensation model,a three-dimensional flow heat transfer model of the condenser's shell is established by considering the conjugate heat transfer at the wall surface.The flow and heat transfer process of the mixture on the shell side are simulated,and the influence of the Impingement Plate on the condensation heat transfer is analyzed.The results show that the condensation heat transfer coefficient increases with the increase of the Reynolds number.On this basis,the numerical simulation of the condenser with different Impingement Plate structure is carried out.The influence of the length,height and opening of the Impingement Plate on the pressure drop,heat exchange and comprehensive performance of the condenser is investigated.The simulation results show that: when the length of the Impingement Plate is L<150mm,the distribution of the flow field is gradually uniform and the overall heat transfer performance is improved significantly;The smaller the height of the Impingement Plate is,the better the heat transfer performance is,but the pressure drop of the shell side increases obviously,which leads to the poor comprehensive performance;The opening of the Impingement Plate is the key to the adjustment of the distribution of the local flow field.Compared with the radial slotting,the average condensation heat transfer coefficient of the condenser with the longitudinal slotting plate is increased by 21%.Finally,the optimum structure of the Impingement Plate is obtained,and its comprehensive performance is up to 21.3% compared to the original condenser.At last,a condenser test system is set up,and the heat transfer performance before and after adding the optimal Impingement Plate to the condenser under different operating conditions is comparatively studied through experiments.The results show that: under the standard conditions,new condenser shell side condensation heat transfer coefficient increased by 15.1%,the total heat transfer coefficient increased by 11.2%,the pressure drop increase by 9.2%;Under non-standard conditions,the new condenser still has a higher heat transfer efficiency,the shell side of the condensation heat transfer performance increased by 11.3%,the average heat transfer coefficient increased by 8.5%,while the pressure drop increased by 8.1%.The strengthening effect of the Impingement Plate was verified,which provided a reference for the enhancement of the condenser shell side and the improved design of the Impingement Plate.