Abstract:
An apparatus includes a regenerator configured to transfer heat to a fluid and to absorb heat from the fluid as the fluid flows between a warm end and a cold end of a cryocooler. The regenerator includes an anisotropic thermal layer configured to reduce a flow of heat axially along the regenerator and to spread the absorbed heat radially or laterally in a plane of the anisotropic thermal layer. The anisotropic thermal layer includes at least one allotropic form of carbon. The anisotropic thermal layer could have a higher radial or lateral thermal conductivity and a lower axial thermal conductivity. The anisotropic thermal layer could include carbon nanotubes and/or graphene. The regenerator could include multiple anisotropic thermal layers that divide the regenerator into multiple segments, where the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.
Abstract:
A system includes a device, a support structure, and a flexure bearing configured to connect the device to the support structure. The flexure bearing includes an outer hub and an inner hub, where the hubs are configured to be secured to the support structure and to the device. The flexure bearing also includes multiple sets of flexure arms connecting the outer and inner hubs. Each set of flexure arms includes symmetric flexure arms. The flexure bearing could include three sets of flexure arms positioned radially around a central axis of the flexure bearing and having a spacing of about 120°. Each flexure arm can follow a substantially curved path between the outer hub and the inner hub. The symmetric flexure arms in each set can be configured such that twisting of one flexure arm in one set is substantially counteracted by twisting of another flexure arm in that set.
Abstract:
An apparatus includes a regenerator configured to transfer heat to a fluid and to absorb heat from the fluid as the fluid flows between a warm end and a cold end of a cryocooler. The regenerator includes an anisotropic thermal layer configured to reduce a flow of heat axially along the regenerator and to spread the absorbed heat radially or laterally in a plane of the anisotropic thermal layer. The anisotropic thermal layer includes at least one allotropic form of carbon. The anisotropic thermal layer could have a higher radial or lateral thermal conductivity and a lower axial thermal conductivity. The anisotropic thermal layer could include carbon nanotubes and/or graphene. The regenerator could include multiple anisotropic thermal layers that divide the regenerator into multiple segments, where the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.