超临界锅炉螺旋管圈水冷壁传热特性的研究

INVESTIGATION ON THE HEAT TRANSFER CHARACTERISTICS OF SUPERCRITICAL PRESSURE BOILER SPIRALLY WATER WALL TUBE

本文在全周均匀加热和侧面半周加热的条件下，对600MW超临界变压运行直流锅炉螺旋管圈水冷壁Φ32×2mm不锈钢管，在倾角α=20°时的传热特性进行了试验研究。试验参数的范围为：压力：p=13～30MPa，质量流速G=600～1200kg／m^2·s，内壁热负荷q=200～600kW／m^2。半周加热时最大热负荷与最小热负荷之比qmax／qmin为4．2，最大热负荷与平均热负荷之比qmax／qav为1．6。试验得出了在不同条件下的壁温分布，发生传热恶化的临界干度、壁温飞升和最小传热系数，比较了半周加热与全周加热的区别，为超临界锅炉设计提供参考。

Under the conditions of full-circumferential uniform heating and half-circumferential side heating, the heat transfer characteristics of the spirally water wall tube with the diameter of φ32 × 2 mm and the inclined angle of α = 20° used in the 600 MW supercritical sliding pressure operation once-through boiler were studied experimentally. The experimental parameters were at pressures p = 13 ~ 30 MPa, mass velocities G = 600 ~ 1200 kg/m2·s, internal wall heat fluxes q = 200 ~ 600 kW/m2. For the half-circumferential side heating, the ratio of maximum and minimum heat flux qmax/qmin was 4.2, the ratio of maximum and average heat flux qmax/qav was 1.6. Based on the tests, the wall temperature profiles, the critical steam qualities, wall temperature rises and minimum heat transfer coefficients at the beginning of boiling heat transfer deterioration were obtained. The difference between half-circumferential and full-circumferential heat was compared. The results may be recommended to be used for the design of supercritical pressure boiler.