Heat transfer tube and heat exchanger using same

Abstract

A heat transfer tube is formed with a corrugated water tube to be used in a heat exchanger, and satisfying 0.04≦Hc/OD, where Hc is the corrugated groove depth of the corrugated tube and OD is the corrugation outside diameter thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments according to the invention will be explained below referring to the drawings, wherein:

FIG. 1A is an explanatory diagram of an entire view showing structure of a heat transfer tube in a first preferred embodiment according to the present invention;

FIG. 1B is an enlarged cross-sectional view in region A of FIG. 1A;

FIG. 2 is an explanatory diagram showing structure of a heat transfer tube in a second preferred embodiment according to the present invention;

FIG. 3 is an explanatory diagram showing structure of a heat exchanger in a third preferred embodiment according to the present invention;

FIG. 4 is an explanatory diagram showing structure of a heat exchanger in a fourth preferred embodiment according to the present invention;

FIG. 5 is an explanatory diagram showing structure of a heat exchanger in a fifth preferred embodiment according to the present invention;

FIG. 6 is an explanatory diagram showing structure of a heat exchanger in a sixth preferred embodiment according to the present invention;

FIG. 7 is an explanatory diagram showing structure of a heat exchanger in a seventh preferred embodiment according to the present invention;

FIG. 8 is a diagram showing the comparison of heat transfer performance of the corrugated heat transfer tube of the first embodiment (example 1), of a plain tube (comparison example 1), and of an inner-grooved tube (comparison example 2);

FIG. 9 is a diagram showing the relationship between Hc/OD and heat transfer performance of the corrugated heat transfer tube, i.e., heat transfer performance ratio relative to a plain tube for Reynolds number Re=1000;

FIG. 10 is a diagram showing the relationship between twist angle βc and heat transfer performance of the corrugated heat transfer tube, i.e., heat transfer performance ratio relative to a plain tube for Reynolds number Re=1000; and

FIG. 11 is a diagram showing the relationship between Hc/OD and friction coefficient of the corrugated heat transfer tube, i.e., tube friction coefficient ratio relative to a plain tube for Reynolds number Re=1000.

Claims

1. A heat transfer tube, comprising: a corrugated water tube to be used in a heat exchanger, and satisfying 0.04≦Hc/OD, where Hc is a corrugated groove depth of the corrugated tube and OD is a corrugation outside diameter thereof.

2. The heat transfer tube according to claim 1, wherein: 0.04≦Hc/OD≦0.1.

3. The heat transfer tube according to claim 1, wherein: a twist angle βc defined between a corrugated groove of the corrugated tube and a tube axis thereof is βc≧40°.

4. A heat exchanger, comprising: a heat transfer tube comprising a corrugated water tube to be used in a heat exchanger, and satisfying 0.04≦Hc/OD, where Hc is a corrugated groove depth of the corrugated tube and OD is a corrugation outside diameter thereof.

5. The heat exchanger according to claim 4, further comprising: an outer tube provided outside of the heat transfer tube that is used as an inner tube, the heat exchanger formed so that a refrigerant flows through an annular portion between the heat transfer tube and the outer tube.

6. The heat exchanger according to claim 4, further comprising: a plain tube sheathed on the heat transfer tube to form a leak detection portion; andan outer tube arranged outside of the plain tube, the heat exchanger formed so that a refrigerant flows through an annular portion between the plain tube and the outer tube.

7. The heat exchanger according to claim 5, wherein: the outer tube comprises a corrugated tube.

8. The heat exchanger according to claim 6, wherein: the outer tube comprises a corrugated tube.

9. A heat exchanger, comprising: a heat transfer tube comprising a corrugated water tube to be used in a heat exchanger, and satisfying 0.04≦Hc/OD, where Hc is a corrugated groove depth of the corrugated tube and OD is a corrugation outside diameter thereof; anda refrigerant-conducting heat transfer tube wound around on the heat transfer tube.