一种用于船舶烟气冷却的喷雾螺旋管冷却器的传热特性研究

Study of Heat Transfer Characteristics of a Spray Spiral Tube Cooler for Marine Flue Gas Cooling

船舶使用的主动降噪设备需要连接到排烟支管,但高温烟气会缩短设备的使用寿命。为了降低烟气温度,建立了冷却器喷雾冷却的数值模型对支管冷却器的运行工况进行优化,通过数值模拟分析喷射压差与喷雾半角对冷态以及热态性能的影响。结果表明:最佳喷雾半角为60°,喷射压差为1.5 MPa时,冷却器性能最佳;采用液滴蒸发效率与逃逸质量分析冷却器内液滴的流动特性,根据模拟结果进行二次回归式拟合,喷雾压差和喷射半角与蒸发效率相关系数分别为0.19和0.56,其相对于逃逸质量的相关系数为0.25和0.72,喷嘴工作参数应选取较高的喷雾半角和较低的喷射压差。

Ships′active noise reduction devices need to be connected to the exhaust branch pipe,but high-temperature flue gas can shorten the device′s lifespan.In order to reduce the flue gas temperature,a numerical model of the cooling spray of the cooler is established to optimize the operating conditions of the branch pipe cooler.Through numerical simulation,the influence of injection pressure difference and spray half-angle on the cold and hot state performance is analyzed.The results show that the optimal spray half-angle is 60°and the optimal injection pressure difference is 1.5 MPa for the best performance of the cooler;the flow characteristics of droplets inside the cooler are analyzed by using the droplet evaporation efficiency and escape mass,and a second-order regression formula is fitted according to the simulation results.The correlation coefficients of spray pressure difference and injection half-angle vs.evaporation efficiency are 0.19 and 0.56 respectively;the correlation coefficients of spray pressure difference and injection half-angle vs.escape mass are 0.25 and 0.72.The nozzle working parameters should choose a higher spray half-angle and a lower injection pressure difference.