Abstract: A tube bundle is provided for a shell-and-tube heat exchanger. The tube bundle includes a plurality of elongated tubes, each of which has an intermediate portion that has a cross section in the form of a flattened circle with at least one axis of symmetry. The tubes are arranged in concentric circles with the axis of symmetry extending tangentially to the circle to facilitate rotational flow of a shell-side fluid.

Abstract: A tube bundle is provided for a shell-and-tube heat exchanger. The tube bundle includes a plurality of elongated tubes, each of which has an intermediate portion that has a cross section in the form of a flattened circle with at least one axis of symmetry. The ends of the tubes may have a circular cross section, with the diameter of one of the circular ends being less than the other end and also less than the length of a shorter axis of symmetry of the intermediate portion of the tube. This tube construction allows the tube bundle to be assembled by inserting the smaller-diameter end of the tube through the aligned openings in the spaced-apart baffles in the tube bundle. The non-circular cross section of the intermediate portion of the tubes increases the tube-side and shell-side heat transfer coefficients.