目的 针对大型冷库系统用螺杆压缩机的型线设计与优化问题，建立型线几何特征计算数学模型，为螺杆压缩机型线设计与优化提供理论依据。方法 以目前广泛采用的GHH型线为研究对象，基于本文采用的型线几何特征计算方法，发现GHH型线的接触线不连续。采用圆弧-圆弧包络线共轭曲线对代替原始GHH型线中的圆弧-圆弧共轭曲线对，实现接触线的连续，提出修正的GHH型线。进而以修正的GHH型线为研究对象，分析节圆半径、齿高、双边长度等型线参数对接触线、啮合线、泄漏三角形等型线几何特征的影响。结果 研究发现，泄漏三角形的面积与节圆半径、导程呈线性正相关，与齿高、双边长度呈线性负相关，其中双边长度对泄漏三角形的面积影响最大。具体地，当节圆半径由48 mm增大至60 mm时，面积利用系数由0.462减小为0.427，接触线长度由174.5 mm增大至182.2 mm，泄漏三角形面积由1.7 mm²增大至8.2 mm²。结论 本文建立了转子型线几何特征快速计算数学模型，对GHH型线进行了优化，实现了螺杆转子接触线的连续，揭示了型线参数对型线几何特征的影响规律，为转子型线优化提供了理论指导。

The work aims to establish a mathematical model for calculating the profile and geometric characteristics specific to the profile design and optimization of screw compressor in large cold storage system, so as to provide theoretical basis for the profile design and optimization of screw compressor. With the widely used GHH profile as the research object, based on the geometric characteristic calculation method adopted, it was found that the sealing line of GHH profile was discontinuous. By replacing the arc-arc conjugate curve pair in the GHH profile with the arc-arc envelope conjugate curve pair, the continuity of the sealing line was achieved, and a modified GHH profile was proposed. Taking the modified GHH profile as the research object, the effect of profile parameters such as pitch radius of female rotor, inner radius of the male rotor and outer radius of the female rotor on the geometric characteristics of contact line, the meshing line and the blow hole was analyzed. The blow hole area was linearly positively correlated with the pitch radius of female rotor, the screw lead and the protection angle, and linearly negatively correlated with the inner radius of the male rotor and the outer radius of the female rotor and the radius of the elliptic arc. The outer radius of the female rotor had the greatest effect on the area of the blow hole. The area utilization rate decreased from 0.462 to 0.427, the length of the sealing line elevated from 174.5 to 182.3 mm and the blow hole area enlarged from 1.7 to 8.3 mm2 when the pitch radius of the female rotor increased from 48 to 60 mm. The established mathematical model for rapid calculation of geometric characteristics of rotor profile optimizes GHH profile, reduces leakage during rotor operation, improves theoretical Engine displacement, and provides theoretical guidance for rotor profile optimization.