NOVELTY - The improved electrochemical cell (10) such as a fuel cell (12) comprises a fluid that is an electrolyte, a unit for creating Taylor-vortex flows in the fluid, a unit for creating circular Couette flows in the fluid, a first cylinder-like electrode (34) rotating relative to and separated by a fluid chamber from a second cylinder-like electrode (36), where one of the electrodes has a catalytic surface layer, protuberances that extend from the surface layer of the electrode into the circular Couette flows, and a fuel reformer (14) located with the second electrode that generates hydrogen gas.    USE - The improved electrochemical cell such as a fuel cell is useful to produce electricity for transmission to an external load (claimed) and to convert chemical energy into electrical energy, and as batteries in vehicles.    ADVANTAGE - The improved electrochemical cell prevents wasteful and dangerous cross-over of fuel and oxidizer within the electrolyte, increases catalytic electrode reaction rates, achieves multiple orders of magnitude higher current densities, and has high performance.    DETAILED DESCRIPTION - The improved electrochemical cell (10) such as a fuel cell (12) comprises a fluid that is an electrolyte, a unit for creating Taylor-vortex flows in the fluid, a unit for creating circular Couette flows in the fluid, a first cylinder-like electrode (34) rotating relative to and separated by a fluid chamber from a second cylinder-like electrode (36), where one of the electrodes has a catalytic surface layer, protuberances that extend from the surface layer of the electrode into the circular Couette flows, and a fuel reformer (14) located with the second electrode that generates hydrogen gas, which enters into fuel cell by penetrating the second electrode. The unit for creating Taylor-vortex flows includes first cylindrical-like electrode enclosing or adjacent to the second cylindrical-like electrode separated from the first electrode by an electrolyte chamber with a gap distance (d) and a gap length (L), and a unit for rotating one electrode with respect to the other at Omega radians per second. The improved electrochemical cell includes a unit for pumping electrolyte into and out of the chamber at a total volumetric exchange rate of U(1)/U, where the U is the volume of electrolyte in the chamber and U(1) is the volumetric rate of flow into and out of the chamber, and a unit for regulating the volumetric exchange rate of axial flow and Taylor number Tc of vortex flow in the electrolyte. In the fuel cell, revolutions per minute (RPM) is Omega / pi and coordinates of d and RPM are within a zone of operable parameters. The first electrode is reactive with a first chemical entering its pores from its first surface to produce a first ion at its second surface layer. The second electrode is reactive with a second chemical entering its pores from its first surface to produce a second ion at its second surface layer and within the first electrode so that a chamber is created between the second surface layers of the two electrodes, where the second ion has a charge different from that of the first ion. The improved fuel cell further comprises a unit for controlling entry of a chemical into pores of an electrode surface layer so that reaction-time to residence-time (ta/tr,) is less than 1/10, and a unit for extracting unwanted contaminants from the electrolyte, a fluid electrolyte is present in the chamber, and a unit for moving one electrode with respect to the other electrode to create flows in the fluid electrolyte so as to generate a voltage across the electrodes that are adapted to be connected to an external electrical circuit. The first and second cylinder-like electrodes are separated by a fluid electrolyte gap between the electrodes. The second surface layer of the first electrode is an inner surface layer. The second surface layer of the second electrode is an outer surface layer that is located parallel to and within the first cylinder-like electrode so as to create the chamber for the electrolyte between the electrodes. The chemical is a reductant and the other chemical is an oxidizer. The electrode catalytic surface layer comprises nanoporous metal foam, which includes pores surrounded by scaffold struts and organic catalyst particles and metal catalyst particles that decorate the scaffold struts, where the metal is platinum metal group and an alloy e.g. ruthenium from the platinum metal group. The electrochemical cell has a first surface that contains a catalyst, a second surface, fluid between the surfaces, and a unit for generating a vortex in the fluid that is enveloped by a laminar shear boundary adjacent to one of the surfaces. The fuel cell includes a cathode electrode, an anode electrode, a fluid electrolyte between the electrodes, and unit for generating vortex in the electrolyte that is enveloped by laminar shear boundary adjacent to one of the electrodes. INDEPENDENT CLAIMS are included for:    (1) a process for operating an electrochemical cell to produce electricity for transmission to an external load; and    (2) a system for enhancing catalyzed reaction rates at porous catalytic surfaces of an electrochemical cell.    DESCRIPTION OF DRAWING(S) - The diagram shows a fragmentary cross-sectional view of an electrochemical cell.    Electrochemical cell (10)    Fuel cell (12)    Fuel reformer (14)    First electrode (34)    Second electrode. (36)