The main jobs of this thesis are as followed: 1 the frame of NC bendtube welding jig CAD system is proposed.
论文的主要工作包括以下几个方面：1提出了数控导管焊接夹具CAD系统框架。
2
The space (11) is equipped with bendtube (17), the outer cylinder and the inner cylinder are opened with hole (5) which is equipped with water inlet pipes.
在空间(11)内装有弯管(17)，在外筒、内筒上制有孔(5)，孔内装有进水管等。
3
The model of three-dimensional flow in circular bendtube which is widely used in gas exchange system of internal combustion engine is developed in this paper.