新型自然循环自动清洗式蒸发器及设计原理

以高效蒸发器为目标，旨在以自然循环替代高能耗的强制循环泵、以自动清洗取代加热面盐垢的周期性停车清洗．主要研究沸腾室内的不平衡汽化过程机理，提出动力温度的新概念，采用显热与汽化热转换平衡的研究方法，得到自然循环推动力的工程设计计算式，并且由此引出推动力强化的基本原则，进而获得中试的成功．还提出加热室必须采用能够低流速下自转清洗又高效传热强化的螺旋齿带，才能保障循环总阻力低于推动力．

DESIGN PRINCIPLE OF THE NEW SELF-CLEANING EVAPORATORS WITH NATURAL CIRCULATION

The main factors that influence the performance of evaporators are the high energy consumption in the forced circulation pump and the cyclic stop ofequipment operation to remove the salt fouling. The self cleaning evaporator with natural circulation can solve such problems satisfactorily. The driving force of natural circulation is obtained based on the concept of dynamic temperature and the process of nonequilibrium vaporization. The calculating model is used to effectively enlarge the driving force of natural circulation. The boiling chamber is designed with large cross-section and depth and gradually increased section at outlet in order to increase the vaporization equilibrium and reduce the kinetic energy lossat outlet. The heat transfer tubes in the heating chamber must be short, in which twisted strip inserts with oblique teeth are installed to efficiently remove salt fouling automatically and to enhance heat transfer with low flow resistance at low fluid flowing velocity, so that the dynamic temperature is raised and the overall resistance of natural circulation is lowered. The industrial experiments of such new evaporators have been successful.