Patent ID: 8414847

Claim:
An apparatus for cooling comprising: a micro channel comprising a wall portion, an inflow opening, and an outflow opening; and a gas comprising a constituent particle; wherein the micro channel is configured to accommodate a flow of the gas from the inflow opening to the outflow opening in a first direction substantially perpendicular to a cross section of the micro channel; wherein the inflow opening has a first cross section area and the outflow opening has a second cross section area substantially different from the first cross section area; wherein the wall portion and the constituent particle are configured such that collisions between the constituent particle and the wall portion are substantially specular; wherein the first cross section has a value in a first range of about 0.01 μm 2 to 500 μm 2 ; wherein the second cross section has a value in a second range of about 0.1 μm 2 to 50,000 μm 2 ; wherein at least a portion of the cross section of the micro channel varies as a function of a length in the first direction between the inflow opening and the outflow opening; and wherein the variation in the cross section of the micro channel as a function of a length in the first direction between the inflow opening and the outflow opening is substantially linear and substantially increasing.