Mini-channel heat exchanger tube sleeve

1. A heat exchanger assembly comprising:

a plurality of adjacent tubes, each tube of the plurality of adjacent tubes comprising:

a first end;

a second end disposed opposite from the first end;

an outer surface;

an inner surface defining an interior space; and

a plurality of channels formed within the interior space;

a first sleeve fixed to the outer surface of a first tube near the first end of the first tube, the first tube belonging to the plurality of adjacent tubes;

a second sleeve fixed to the outer surface of the first tube near the second end of the first tube;

a second tube belonging to the plurality of adjacent tubes;

a third tube belonging to the plurality of adjacent tubes;

a first manifold body that bounds a first cavity, wherein the first manifold body has a first side and a second side;

a plurality of first slots defined by the first manifold body configured to receive a first portion of the first tube, a first portion of the second tube, and a first portion of the third tube, wherein the first portion of the first tube includes the first end of the first tube;

a second manifold body that bounds a second cavity;

a plurality of second slots defined by the second manifold body configured to receive a second portion of the first tube, a second portion of the second tube, and a second portion of the third tube, wherein the second portion of the first tube includes the second end of the first tube;

a first baffle disposed in the second manifold body between the first tube and the second tube, the first baffle being configured to allow fluid flow from the first tube to the second tube; and

a first wall disposed in the second manifold body between the second tube and the third tube, the first wall being configured to prevent fluid flow from the second tube to the third tube;

wherein the first end of the first tube terminates within one of the plurality of first slots between the first side and the second side;

wherein the first sleeve is adjacent to the first manifold body and entirely outside of the first cavity; and

wherein a thickness of the second sleeve is less than a thickness of the first sleeve.

2. The heat exchanger tube assembly of claim 1 , wherein the thickness of the first sleeve is greater than or equal to a thickness of the first tube.

3. The heat exchanger assembly of claim 2 , wherein the thickness of the first sleeve is no more than three times greater than the thickness of the first tube.

4. The heat exchanger assembly of claim 2 , and further comprising:

a third sleeve fixed to an outer surface of the second tube belonging to the plurality of adjacent tubes, the second tube being adjacent to the first tube,

wherein the first end of the second tube terminates within another one of the first plurality of slots;

wherein the third sleeve is adjacent to the first manifold body and entirely outside of the first cavity; and

wherein a thickness of the third sleeve is less than the thickness of the first sleeve.

5. The heat exchanger assembly of claim 1 , wherein the plurality of channels are defined by a plurality of integral ribs extending across the interior space of each tube of the plurality of adjacent tubes.

6. The heat exchanger assembly of claim 1 , wherein the plurality of channels are defined by a brazed insert.

7. A method of constructing the heat exchanger assembly of claim 1 , the method comprising the steps of:

coating an outer surface of the first tube with a flux material;

coating an inner surface of the first sleeve with the flux material;

positioning the inner surface of the first sleeve about the outer surface of the first tube, wherein a first gap is formed therebetween;

heating the first tube and sleeve to a brazing temperature; and

filling the first gap with a filler metal.

8. The method of claim 7 , and further comprising:

coating a slot defined by an inner surface of a manifold with the flux material;

positioning one of the outer surface of the first tube or the outer surface of the first sleeve within the slot, wherein a second gap is formed therebetween; and

filling the second gap with a filler material.

9. The heat exchanger assembly of claim 1 , wherein an end of the first sleeve abuts the first manifold body.

10. The heat exchanger assembly of claim 1 , further comprising:

a second wall disposed in the first manifold body between the first tube and the second tube, the second wall being configured to prevent fluid flow from the first tube to the second tube; and

a second baffle disposed in the first manifold body between the second tube and the third tube, the second baffle being configured to allow fluid flow from the second tube to the third tube.