The prediction using a universal correlation of the shell side Nusselt number with the Reynolds number for helical baffle heat exchangers (HBHXs) has been in vain, because of the impropriate formula of the cross-section area of helical channel or the flow velocity. The shell side friction factor is of similar situation. A new model of mass center equivalent rectangle (MCER) is proposed to calculate the cross-sectional area of the helical flow channel of the HBHX with the hypothesis that the parameters on the mass center cylinder can represent the mean values of the spiral channel. Taking helix pitch as hypotenuse and two sides of the right triangle are along the mass center equivalent helix angle and its normal direction, and the latter and the radius of the shell are postulated to be the two edges of the windward rectangle. The flow cross-section area of the helical channel is the rectangle area subtracting the total ellipse area of the tubes in the rectangle area. The verification of the model is quite satisfactory for quadrant HBHXs by both the heat exchanger design software HTRI and the existing experimental results in a master thesis with the deviations of h_o·Pr_o^-1/3∼Re_o are respectively within +17%∼-10% and ±18%. The verification of the model is also satisfied with experimental results of a trisection circumferential overlap HBHX. The coefficients in the correlation formulas especially for the friction factor need be further consummated relating to the helical baffle type and baffle connection style of the HBHXs.

由于螺旋通道横截面积或流速的公式不正确，使用壳侧Nusselt数与雷诺数的通用相关性进行螺旋折流换热器（HBHXs）的预测是徒劳的。壳侧摩擦系数也类似。提出了一种新的质心当量矩形模型（MCER）来计算HBHX螺旋流道的横截面积，并假设质心圆柱体上的参数可以代表螺旋流道的平均值。以螺旋螺距为斜边，直角三角形的两个边沿重心等效螺旋角及其法线方向，假定后者和壳体半径为上风矩形的两个边缘。螺旋通道的流动横截面面积是矩形面积减去矩形面积中管的总椭圆形面积。通过热交换器设计软件HTRI和已有的实验结果（偏差为）对象限HBHX进行的模型验证是令人满意的。ħ _ö ·镨_ö ^-1/3 ~Re _ö分别在+ 17％〜 - 10％和±18％。三等分周向重叠HBHX的实验结果也满足该模型的验证要求。与HBHX的螺旋折流板类型和折流板连接方式有关的相关公式中，尤其是对于摩擦系数的系数需要进一步完善。