Falling film evaporator

A fluid flow member, comprising

• A. a closed first end;
• B. a second end having a generally cylindrical cross section, wherein a central longitudinal axis is defined by a line extending from a center point of the closed first end to a point at the center of the generally cylindrical cross section of the second end, and wherein the second end is open, thus forming an inner chamber accessible via the second end;
• C. a variably curved outer flow surface extending from the closed first end to the second end, the surface having two fluid flow regions, namely,
• i. a fluid dispersal region extending from the first end to a point between the first end and second end, the fluid dispersal region being defined by a surface curvature that produces an increasing surface area as the region extends from the first end toward the second end along the central longitudinal axis;
• and,
• ii. an active region extending from a point below the fluid dispersal region, the active region having a decreasing surface area as the region extends along the central longitudinal axis in a direction away from the fluid dispersal region and toward the second end wherein the rate of decrease in the active region surface area is selected to maintain an approximately constant fluid film thickness within the active region.

A falling film evaporator comprising:

• A. a liquid inlet;
• B. a generally vertical evaporation member having a closed first end, an open second end, a variably curved outer surface and an inner surface, wherein,
• i. the inner surface is configured to received a heated fluid via the open second end;
• and,
• ii. the outer surface has two fluid flow regions, namely,
• a. a fluid dispersal region beginning near an upper end of the member and extending in a generally downward direction;
• and,
• b. an active region extending in a generally downward direction from a point below the fluid dispersal region, the active region having a surface curvature with a decreasing surface area as the region extends along the central longitudinal axis in a direction away from the fluid dispersal region and toward the second end wherein the rate of decrease in the active region surface area is selected to maintain an approximately constant fluid film thickness within the active region.

A method of controlling laminar fluid flow over a surface, comprising:

• A. depositing a fluid on the surface such that laminar flow of the fluid results;
• B. rapidly thinning the laminar fluid flow layer by flowing the fluid over a fluid dispersal region of the surface, wherein the fluid dispersal region has an increasing surface area in the direction of the fluid flow;
• and,
• C. flowing the fluid over an active region of the surface, wherein the active region has a decreasing surface area as the region extends along a central longitudinal axis in a direction away from the fluid dispersal region;
• and,
• D. controlling the laminar fluid flow layer thickness within the active region to achieve a desired result.