Reactor with upper and lower manifold structures

A reactor comprising a reactor substrate, an upper manifold structure, and a lower manifold structure, wherein:

• the reactor substrate comprises a plurality of interior substrate channels that extend between the upper and lower manifold structures;
• the interior substrate channels of the reactor substrate are delineated into a plurality of relatively short open-ended channels and at least one relatively long serpentine channel;
• the relatively long serpentine channel extends from a reactant inlet portion to a reactant outlet portion and comprises a relatively long serpentine flow path comprising flow path segments in adjacent ones of the interior substrate channels;
• the upper and lower manifold structures comprise an inlet region and an outlet region;
• the upper manifold structure comprises a plurality of U-bend flow directing cavities in fluid communication with at least one relatively short open-ended channel;
• the lower manifold structure comprises a plurality of U-bend flow directing cavities in fluid communication with at least one relatively short open-ended channel;
• the upper manifold structure and the lower manifold structure each comprise at least one flow directing cavity that reverses a flow direction of a fluid flowing through the relatively short open-ended channels between the upper and lower manifold structures;
• the flow directing cavities of the upper and lower manifold structures are configured to direct fluid from the inlet region to the outlet region in an additional serpentine path defined by the flow direction reversals introduced by the upper and lower manifold structures;
• the upper and lower manifold structures are aligned relative to the relatively short open-ended channels to direct flow through the relatively short open-ended channels from the inlet region to the outlet region along a flow path that progresses successively through individual ones of the U-bend flow directing cavities in the upper and lower manifold structures;
• the cross-sectional flow area of a U-bend flow directing cavity positioned along a selected portion of the flow path is smaller or larger than the cross-sectional flow area of one or more U-bend flow directing cavities that are positioned along a different portion of the flow path;
• and
• the portion of the flow path that comprises the smaller cross sectional flow area is most directly thermally coupled to the reactant inlet portion of the relatively long serpentine channel.