列管式反应器管束间流体流动与沸腾传热研究

Fluid flow and boiling heat transfer between tube bundles in tubular reactor

采用RPI壁面沸腾模型与PBM模型对列管式反应器管束间流动沸腾现象进行模拟计算,引入场协同理论分析分布板的强化传热机理,研究开孔大小与开孔形状对棒束通道流动与传热的影响规律。模拟结果表明,分布板对棒束通道内沸腾过程起到强化传热的作用,同时具有破碎气泡的能力,然而气相会在板上积聚形成气膜,出现传热恶化的现象;减小环隙宽度可强化分布板破碎气泡的能力,提高棒束通道内的温度与速度的场协同性;环隙与圆孔的组合开孔方式虽然会弱化分布板强化传热的能力,但能缓解板前传热恶化与板后气相死区等问题,降低分布板的压降。

Flow boiling between tube bundles in a tubular reactor was simulated by the RPI wall boiling model and PBM model.The field synergy principle was employed to analyze the distribution plate’s enhanced heat transfer mechanism and investigate the impact of opening size and shape on flow and heat transfer in the rod bundle channel.The results indicate that the distribution plate enhances heat transfer during the boiling process in the rod bundle channel and can break up bubbles.However,the accumulation of the gas phase on the plate forms a gas film,leading to heat transfer deterioration.When the annulus width is decreased,the plate’s bubble breaking capability can be enhanced,and field synergy between temperature and velocity in the rod bundle channel can be increased.The combination of annulus and round holes weakens the distribution plate’s capability to enhance heat transfer.However,the combination can relieve problems of heat transfer deterioration and gas phase dead zones behind the plate,reducing the pressure drop of distribution plates.