I post this summary research relating to a Striling operating with cams, without knowing in which category alpha / beta / gamma to classify it ...
The hot source consists of 2 sides with fins (bright red + red), the mobile piston of 2 sides with fins (pink, light blue) separated by an insulator, and finally the cold source of 2 sides with fins (blue and ultramarine blue) ). The cold source is pierced to allow the rods moved by the piston cam to pass. I only drew 2 rods and a 2x180 ° cam but ideally it would take 3 and a 3x120 ° tripe geometry cam ...
The theoretical Stirling cycle is characterized by isochoric heating, isothermal expansion, isochoric cooling and finally isothermal compression. The advantage of cams is to be able to manage the displacement of the pistons independently, and therefore to respect the 4 moments of the cycle, while minimizing the intermediate phases of the real cycle.
The adoption of pistons having a large exchange and contact surface makes it possible to optimize the transfer of heat exchanges between hot source and 'hot' piston and cold source and 'cold' piston, and between them and the gas. The dead volume is almost zero.
The gas transfer between the hot and cold zones is done by multiple bores through the piston (to minimize the speed / pressure drop in the bores) and the insulating zone which separates its hot and cold faces.
It should also be noted that there is no regenerator: if the dead volume is very small compared to the useful volume, the regenerator becomes useless.
Here, for convenience, the jacket is not visible, the hot source is stationary, the cold source moves, the double-sided piston also moves more significantly, depending on the compression ratio envisaged.
Clearly, the displacement of the piston and the cold source is done as follows (sorry a video would have been better, but I did not find a way to include it):
- isochoric heating: the piston and the cold source are stationary in an intermediate position, the cold piston cools on contact with the cold source, the gas is in the high volume, heated between the fins;
- isothermal expansion: the piston and the cold source descend at the same time, the cold volume remains zero;
- isochoric transfer: the piston is raised in contact with the hot source, causing the transfer of gas to the cold zone, the cold source remains stationary;
- isochoric cooling: the piston and the cold source are stationary, the gas cools on contact with the cold fins;
- isothermal compression: the cold source rises, the piston remains in contact with the hot source;
- isochoric transfer: the piston descends in contact with the cold source which remains stationary, the gas passes into the hot zone.
Mechanical energy is recovered by a flywheel integral with the cams.