Buy Aluminum

"The plant, which provides about 10% of Siberia's energy needs, was expected to take several years and billions of roubles to fix."

I've got $15, let's fix the place.

i was hoping the opposite would be true too, "SELL aluminum". stopped by the scrap man today, was hoping he was going to tell me aluminum prices are off the charts, he said he's buying cast at $0.35 and extrusions at $0.50. ok but not unbelievable. he hadn't heard about the hydroelectric dam catastrophe in russia, i told him i read the aluminum plant near the dam produces 30% of the world's aluminum, he told me (can't remember exactly but it was something about) some organization in london england has stockpiles of aluminum enough to last for the next 150 years, so he was saying aluminum prices aren't going to fluctuate that much, at least scrap prices.

b.w.

How long did the turbines at Hoover dam go before they were rebuilt?

50 years?

Thank You, Randy

Remove 333 from email address to reply.

Let us now if you find anything out, I am interested.

i

On Tue, 25 Aug 2009 09:02:49 -0400, the infamous Randy scrawled the following:

Yabbut, they weren't Russian-built...

38 years without a problem

Thank You, Randy

Remove 333 from email address to reply.

Water jet cutting is usually done a pressures of 50,000 to 80,000 psi, and an abrasive is added to enhance the cutting process.

Cavitation damage is caused by impingement pressures of 200,000 to

300,000 psi. Hard to believe, I know, but the collapsing bubble wall forms a spike that impinges onto the surface with such velocity that these pressures are achieved.

On modern hydraulic turbines several things can be done to decrease and slow down this damage:

1) in cavitation prone areas use a material with a high work function ie. a material that requires a lot of energy to remove bits. Examples are 10% aluminum bronze and 17-4 ph heat treated stainless steel.

2) design the flow passages so that cavitation bubbles separate from the flow guides/turbine surfaces thus, when the bubbles collapse, they are removed from any surfaces. This is not an easy task and much modelling work is required to get a good grip on this; even then some of the professors get it wrong:-)).

3) add compressed air to the water just upstream of the turbine.

Old hydraulic turbines are often refurbished to increase their efficiencies. On large machines, say 400 Mw and up, 94% efficiency is claimed by some manufacturers.

Smaller machines are refurbished to re-establish original output. Over the years some turbine blades may have been knocked-out or badly bent because of ingestion of scrap iron such as steel fence posts. In order to get the machine up-and-running as quickly as possible the maintenance people would simply remove a diametrically opposite blade and re-water the unit. Of course power production is seriously impaired but electricity is produced. The full repair is then scheduled during low water periods or when finances permit.

Modern turbine runners have odd numbers of blades or buckets and this type of "repair" cannot be used.

Wolfgang

jeez, they showed on modern marvels (or some such)(maybe it was dirty jobs?) them replacing individual turbine blades, i can't remember if it was hoover dam, but maybe (now i can't even remember if they were only replacing individual blades or the entire turbine). showed the back sides of the blades are eroded by cavitation. was FASCINATING to think water (i mean, not water under 20,000 lb. of pressure like a water jet cutter) can erode (whatever kind of) metal (it was). i assumed after seeing that (modern marvels/dirty jobs) they have regular (fastidious) monitoring and maintenance. that's what i wondered after seeing the russian video, if like a turbine blade broke off (or part of a blade) and smashed the others on it's way out and that ruptured the housing or sumphin'. i mean, they replace the blades on the hoover dam(?) i assume for a GOOD reason. i think it's unwise to ridicule the russians, bad karma.

b.w.

I am sure the lake water from Lake Meade also contains some abrasives.

Why an odd number - harmonics?

Can't speak for Hoover, but I know for a fact that the turbines and generators at Wanapum Dam on the Columbia River got their first major overhaul at right around 30 years.

The generators are pulled and checked a lot more than 30 years. When we are Hoover Dam last Thanksgiving, they had one generator pulled. Impressive to see the size of the armature and that is takes two traveling cranes to lift it, and not much clearance.

I got a nice PPS slide show on the dam accident sent to me, if anyone wants it, email me and I'll send it to you.

Thank You, Randy

Remove 333 from email address to reply.

I saw that last night. Worth a look, definitely