Results with Loads offering Resistance to Flow

For analysis of the accelerator models efficiency, with loads offering resistance to flow, several graphs were plotted:

• Characteristic of the ratio Vt/Vc between the flow velocity Vt measured before the load (for Loads L1, L2, and L3) in the narrower channel zone and the stream velocity Vc, as a function of the stream velocity Vc.

• Characteristic of the pressure P measured transversaly to the flow direction before the load (for Loads L1, L2, and L3) in the narrower channel zone, as a function of the stream velocity Vc.

• Characteristic of the pressure P measured transversaly to the flow direction before the load (for Loads L1, L2, and L3) in the narrower channel zone, as a function of the velocity Vt at the same point.

• Characteristic of the available Head -DH before the turbine, as a function of the flow velocity Vt, given by the expression -DH = (Vt²/2g) + P/g .

Load L1

58% obstruction

Load L2

72% obstruction

Load L3

82% obstruction

Load L1

58% area obstruction

Load L2

72% area obstruction

Load L3

82% area obstruction

Analysis of Results with Loads offering Resistance to Flow

• Model A1 causes for a considered stream velocity Vc, higher flow velocity Vt and transversal pressure P before a specific Load than Model A2. Consequently the available head -DH before a specific Load is higher for Model A1 than for Model A2. The results confirm that Model A1 is more efficient than Model A2.

• For a specific stream velocity Vc, the flow velocity Vt is as more higher as less obstructing is the Load located in the narrower channel zone.

• As more obstructing is Load, higher is stream velocity Vc beyond which starts flowing through the channel. The results show, that with 82% channel area obstruction (Load L3), the stream velocity Vc beyond which starts flowing is 1 m/s (2 knots) with Model A1 and 1,25 m/s (2,5 knots) with Model A2. The stream velocity Vc beyond which starts flowing tends to 0,75 m/s (1,5 knots) or to 0,5 m/s (1 knots) for Model A1 respectively with 72% channel area obstruction (Load L2) or 58% channel area obstruction (Load L1).

• For a specific stream velocity Vc, the available head -DH before the Load, is almost independent of the used Load (L1, L2 or L3), being equivalent to the available head through this zone in the absence of any flow constraints. This is only valid for not extremelly obstructing Loads that do not imply rejection of energy flow through the channel. The following table resumes the results obtained with Model A1, for stream velocities of 1,25 m/s (2,5 knots) and 1,75 m/s (3,5 knots).