Abstract:
The maximum power of Feynman’s ratchet as a heat engine ( ) and the corresponding
efficiency ( ) are investigated by optimizing both the internal parameter and the external load.
When a perfect ratchet device (no heat exchange between the ratchet and the paw via kinetic
energy) works between two thermal baths at temperatures
, its efficiency at maximum
power is found to be
, where
is Carnot’s efficiency, which
is slightly higher than the value √
√ obtained by Curzon and Ahlborn for
macroscopic heat engines. It is also slightly larger than the result
obtained by Schmiedl
and Seifert for stochastic heat engines working at small temperature difference and the maximum
power of Feynman’s ratchet as a heat engine in this model is
, e is natural
exponent and is a constant with dimension second inverse
. By developing objective
function for optimization of this thesis engine model, fixing some parameters of the objective
function plot objective function ( ̇) versus external parameter (z) then extract the value of external
parameter (z) from peak point of the plot to optimize power and efficiency of Feynman’s ratchet as
a heat engine numerically. Hence numerically, maximum power is , efficiency at
maximum power is , the optimized power is and the optimized
efficiency is . The overall performance of this work is a proximately greater than unity
