To have an elbow bend in a pipe of diameter D, the bend radius R should be > D.  However, you don’t need an elbow bend to solve the problem as shown.

It doesn’t look nice, but it is perfectly acceptable to have a Finite Element model using Beam elements with a Tube cross-section meet at a point with a 90 degree angle between them.  Just work with the lines and ignore the rendering of the cross-sections.  However, your image of the tube cross-sections seems to show two lines that cross each other and did not stop at the point of intersection, is that true?  If so, you must have lines that end at the intersection.