在采用一体化布置的高温气冷堆中，为了使预应力混凝土压力容器体积不致过大，蒸汽发生器应尽量紧凑，严格限制受热面空间布置，并要求其具有较高的功率密度。因此，一体化布置的高温气冷反应堆主要选用直流型多头螺旋管式蒸汽发生器。
本文从实际工程设计出发，对多头螺旋管式蒸汽发生器的设计进行了研究，提出了多头螺旋管束受热面结构的设计方法，推荐了螺旋管内外的传热系数和压降的计算关系式。根据所提出设计方法和螺旋管内外的传热系数和压降的计算关系式对260MW蒸汽发生器进行了设计计算。
由于螺旋管具有占地面积小、传热系数大、结构紧凑、易于清洗、污垢热阻小等优点，不仅在核反应堆，而且在直流锅炉、急冷锅炉、各种石油化工设备中的换热器，热交换器都有相当广泛的应用。因此本文得到的结果不仅适用于高温气冷反应堆的蒸汽发生器，而且适用于各种工业设备中的螺旋管式换热器和螺旋管式热交换器。
关键词 蒸汽发生器，传热，压降，螺旋管
The steam generator, in the incorporate type of the high-temperature gas-cooled reactor, should be of the compact structure, the least heating surface and the higher power density in order to decrease the volume of the initial-stress concrete pressure vessel, there by the steam generator with the uniflow multi-start helical coiled tubes is used generally for it possessing all these characteristics.
Design method of the heat exchanger with multi-start helical coiled tubes is researched to meet of engineering practice. The structure design of multi-start helical tubes bundle is present. The correlations to caculate heat transfer coefficient and pressure drop for the inside and out side of helical coild tubes are commended. The design calculation of 260MW steam generator has been done.
There are a number of obvious advantages in the banks of helical tubes: they occupy less area; they exhibit high heat transfer coefficients and low thermal resistances; they are of the compact structures; and finally, they can be cleaned out easily. Therefore helical coiled tubes are used in many industries, for example in the nuclear reactor, in the monotube boiler and the rapid-cooling boiler, in the heat exchangers of the petrochemical equipments. So the results presented in this paper are fit not only for the steam generator in the high-temperature gas-cooled reactor, but also for the heat exchangers with helical coiled tubes in all kinds of industry equipments.
Key Word: steam generator，heat transfer， pressure drop，helical coiled tubes
