Fluid channels having performance enhancement features and devices incorporating same

A fluid channel for transmitting a fluid therethrough, comprising:

• first and second spaced apart walls, the first and second spaced apart walls each defining an inner surface and an outer surface;
• a flow passage defined between the inner surfaces of the first and second spaced apart walls;
• a fluid inlet in communication with a first end of said flow passage for delivering said fluid to said flow passage;
• a fluid outlet in communication with a second end of said flow passage for discharging said fluid from said flow passage;
• a plurality of performance enhancement features formed in the inner surface of at least one of the first and second spaced apart walls of the tubular member;
• and
• wherein the performance enhancement features are in the form of spaced apart protuberances that protrude out of the inner surface of the at least one of the first and second spaced apart walls while the outer surface of the at least one of the first and second spaced apart walls provides a generally continuous contact surface that is free of perforations, each protuberance having a pair of sharp leading edges generally directed towards incoming fluid flow.

A heat exchanger, comprising:

• a plurality of tubular members arranged in spaced apart generally parallel relationship to each other, each tubular member forming a fluid channel having first and second spaced apart walls, the first and second walls each defining an inner surface and an outer surface;
• a plurality of first fluid flow passages defined between the inner surfaces of the first and second spaced apart walls of each of the tubular members;
• a plurality of second fluid flow passages, each second fluid flow passage defined between adjacent tubular members;
• a pair of inlet and outlet manifolds in communication with said first set of fluid flow passages for inletting and discharging a fluid through said first fluid flow passages;
• a plurality of performance enhancement features formed on the inner surface of at least one of the first and second spaced apart walls of each of the tubular members;
• wherein the performance enhancement features are formed with a pair of sharp leading edges, the performance enhancement features protruding out of the plane of the inner surface of the at least one of the first and second spaced apart walls, the outer surface of the at least one of the first and second spaced apart walls providing a generally continuous contact surface free of perforations;
• and
• wherein:
• the performance enhancement features are heat transfer enhancements, the heat transfer enhancements being in the form of triangular-shaped protuberances having a tip and a base, the tip being oriented generally upstream from the base;
• the heat transfer enhancements are formed in a plurality of rows, the rows extending along the length of the inner surface of the at least one of the first and second walls;
• the adjacent rows of heat transfer enhancements are spaced apart from each other along the width of the tubular member;
• and
• the adjacent rows of heat transfer enhancements are arranged proximal to each other forming a saw-tooth arrangement across the width of the tubular member.

A heat exchanger, comprising:

• a plurality of tubular members arranged in spaced apart generally parallel relationship to each other, each tubular member forming a fluid channel having first and second spaced apart walls, the first and second walls each defining an inner surface and an outer surface;
• a plurality of first fluid flow passages defined between the inner surfaces of the first and second spaced apart walls of each of the tubular members;
• a plurality of second fluid flow passages, each second fluid flow passage defined between adjacent tubular members;
• a pair of inlet and outlet manifolds in communication with said first set of fluid flow passages for inletting and discharging a fluid through said first fluid flow passages;
• a plurality of performance enhancement features formed on the inner surface of at least one of the first and second spaced apart walls of each of the tubular members;
• wherein the performance enhancement features are formed with a pair of sharp leading edges, the performance enhancement features protruding out of the plane of the inner surface of the at least one of the first and second spaced apart walls, the outer surface of the at least one of the first and second spaced apart walls providing a generally continuous contact surface free of perforations;
• and
• wherein:
• the performance enhancement features are heat transfer enhancements, the heat transfer enhancements being in the form of triangular-shaped protuberances having a tip and a base, the tip being oriented generally upstream from the base;
• the heat transfer enhancements are formed in a plurality of rows, the rows extending along the length of the inner surface of the at least one of the first and second walls;
• the adjacent rows of heat transfer enhancements are spaced apart from each other along the width of the tubular member;
• and
• the adjacent rows of heat transfer enhancements are arranged in one of the following alternative patterns:
• staggered with respect to one another, or cascading with respect to one another.

A method of making a fluid channel for a heat exchanger, comprising the steps of:

• providing a sheet of material having a thickness and defining an inner surface and an outer surface;
• forming a plurality of heat transfer enhancements in said sheet of material in a pattern over the inner surface of said material, said plurality of heat transfer enhancements having sharp leading edges and projecting out of the inner surface of the sheet of material, the outer surface of the sheet of material remaining generally continuous and free of perforations;
• cutting said sheet of material to a desired size;
• forming the cut sheet of material into the shape of an elongated tubular member;
• and
• sealing a peripheral edge of said elongated tubular member so as to define a fluid channel for transmitting a fluid therethrough by brazing.

A humidifier, comprising:

• a plurality plates arranged in a stack, each of said plates defining a plurality of fluid channels in the form of gas flow passages for either a first gas stream or a second gas stream;
• a plurality of water permeable membranes, wherein one of said membranes is provided between each pair of adjacent plates in said stack, and is sealed to said pair of adjacent plates;
• wherein said plates are stacked such that gas flow passages for said first gas stream alternate with gas flow passages for said second gas stream throughout said stack, and such that each of the water permeable membranes separates one of the gas flow passages for the first gas stream from one of the gas flow passages for the second gas stream;
• and
• wherein the gas flow passages for at least one of said first gas stream and said second gas stream further comprise performance enhancement features in the form of mass transfer enhancement features that protrude out of the surfaces of the gas flow passages, the mass transfer enhancement features having a pair of sharp leading edges generally directed towards incoming flow for forming vortices within the one of said first and second gas streams.