Non-isotropic structures for heat exchangers and reactors
A Non-Isotropic Structure for a Heat Exchanger (NISHEX) that forms fins from nested woven wire meshes. The wire meshes are shaped into channels that are stacked on top of each other to produce a non-isotropic fin structure having multiple fin layers. The fin structure exhibits a high heat coefficient while maintaining relatively high fin efficiency through the selection of fin lengths in proportion to the wire diameter in the mesh fins.
1. A heat exchanger construct, comprising:
a plate having a first side surface and a second side surface, opposite the first side surface;
a non-isotropic fin bonded to the first side surface and formed by first and second woven wire meshes,
wherein the first wire mesh is corrugated, thereby forming a series of parallel ridges and grooves, including a plurality of first portions extending parallel to the first side surface, and a plurality of second portions forming first channels extending along a mean flow direction through the heat exchanger,
wherein the second wire mesh is corrugated, thereby forming a series of parallel ridges and grooves, including a plurality of first portions extending parallel to the first side surface, and a plurality of second portions forming second channels extending along a mean flow direction through the heat exchanger,
wherein a length and diameter of first wire mesh wires is greater than a length and diameter of second wire mesh wires, wherein the lengths are measured as maximum distances away from the first side surface,
wherein the second channels nest within the first channels, and
wherein the first portions of the first and second woven wire meshes are directly connected to each other and/or the first side surface; and
further including a third corrugated wire mesh forming channels, wherein the third corrugated wire mesh channels are located between the first channels and the first side surface, and wherein the third corrugated wire mesh wires have a length and diameter less than the respective length and diameter of second corrugated wire mesh wires.
2. The heat exchanger construct of claim 1 , wherein the fin effectiveness (F eff ) for the first wire mesh wires and second wire mesh wires is approximately equal to
tan h (mL)/mL
where L is the length of the first wire mesh wires and second wire mesh wires, respectively, m=(4 h/kd) 1/2 , h is the gas heat transfer coefficient, k is the thermal conductivity of the first woven wire mesh material and the second woven wire mesh material, respectively, and d is the diameter of the first wire mesh wires and second wire mesh wires, respectively.