At which point, it is no longer a reaction turbine, it's an impulse turbine. They can use high head application, but like you said, you're using water momentum, not pressure to drive the blades. Because the wheel is spinning at 1/2 speed of the water jet, the actual force on the blades is not astonomical.Due to the momentum and viscosity of water, they do not need to.
Simply saying "It can be done" doesn't either.Well this is a rather inane remark. Since you chose not to address the science/physics/engineering issue directly,
There's a big difference between not practical and not doable. There is reason behind one. It's not practical to drive a Hummer. However, if I have the money to do so and feel the need to look cool, why the hell not?I'm flummoxed by your, Fred's, and others' errant belief that I am in any way proposing single-stage designs, particularly given my oft-repeated "possible, but not practical" mantra.
Could there be reason for a single-stage axial machine like you're describing? Sure, perhaps there are packaging concerns, maybe a single-stage can cost less than multi for a limited life application. However, if one of our customers came to us and asked for such a machine, we would respecfully decline, and not because it's not practical.
Well, in all honesty, we'd probably take the cabbage and then just not deliver (either on time or meeting goals). You know, the usual.