Difference between revisions of "Mechanical energy transmission"

Revision as of 14:25, 26 January 2014

Due to the very high energy densities that are handleable with diamondoid nanosystems [reference needed] and the available superlubrication energy could potentially transmitted mechanically.

Energy could be transmitted via translative or rotative or combined movement of diamondoid rods. For translative movement any diamondoid rods can be employed. For rotative movement strained shell diamondoid rods or nanotubes are suited best. For continuous pulling flexible belts ropes or chains can be considered.

Power is force times speed (corresponding to voltage times current).

• The force is limited by the tensile strength of the used rods.
• The speed is limited by the turn radius and thus indirectly by the tensile strength of the housing structure.

When speed is increased speed dependent friction rises. This can be limited by the use of infinitesimal bearings as concentrical cylindrical shells along the whole length of the cable. With rising speeds centrifugal forces become exceedingly high making beefy supporting structures necessary. Power densities beyond the already very high limit for diamondoid systems are then accessible and cable damage becomes a very serious hazard. For lower power densities and lower speeds sharp bends are still problematic because of the limited flexibility (bendability) of such cables. Specially designed turning elements may be usable.

For medium long to very long distances one can meet the limit of specific strength that is the rods can't turn/pull their own inertial weight anymore. This limits the power-up rate (unit: watts per second). energy cells [Kickstart with interfacial drives to circumvent this ?] The energy transfer speed (propagation of the rising flank after power-up) is equal to the (very high) transversal or longitudinal speed of sound of the choosen diamondoid material and thus significantly slower than electrical impulse propagation. The maximum speed of continuous axial movement is not limited by the speed of sound though. For all practical purpouses this limit is so high that it wont matter much. Continuous rotative, alternating rotative and reciprocative movement might have benefits for all but power densities so high that they require global scale bending radii (cables carrying speeds exceeding c_sound in diamond).

Example: Limit for areal power density:
50GPa ... ~ tensile strength of natural diamond - mechanosynthetisized one will be stronger
c_sound ... the longitudinal speed of sound in diamond

• 1000th c_sound: 50GPa * 18m/s = 900GW/m² = 9GW/dm² = 90MW/cm² = 900kW/mm²
• 100th c_sound: 50GPa * 180m/s = 9TW/m² = 90GW/dm² = 900MW/cm² = 9MW/mm² (seems practical)
• 10th c_sound: 50GPa * 1.8km/s = 90TW/m² = 900GW/dm² = 9GW/cm² = 90MW/mm²

[Todo: Compare to expensive overhead power line ~ 1MW/mm²]

To minimize acoustic losses in the environment a (high) number of litzes/strands operated in different phases can be combined. Elastic losses translate to capacitive losses in electrical lines. Rotation has higher stiffness but also higher speed dependent power dissipation [to verify]. Translation has lower stiffness and lower speed dependent power dissipation [to verify].

Alternate uses

Beside energy transport continuous linear movement cables could be used for the forces they develop. When curvature and speed produces forces exceeding gravitational acceleration (note that there is no need for escape velocity) the cable could (very speculatively) lift by itself and build a launch loop. When such a cable is cut a big scale explosion may follow depositing lots of material at the explosion site.