I calculated 0.385 kg s-1 for the mass flow for 1MW heat source.
This uses 129 kW for heating the make up at equilibrium with 874 Kw left for latent.
0.385 kg s-1 * 2.2 lb/kg * 60s = 50.82 lbs/min
If you look at table 66 for a dp of 1 psi , 50lbs/min of steam for a 2 inch pipe is off the chart > 150 psig.
The point is sonic flow conditions (choked flow) are not desirable as they limit the flow unless pressure is increased.
Yes table 66 shows that a 2" pipe is totally insufficient for this reactor. However the video of the inside of the shipping container in the ny teknik article http://www.nyteknik.se/nyheter/energi_m ... 264361.ece shows that the internal pipe diameter that leads to the 2" outlet is much larger. If it is as much as 4" then table 66 shows that it can support the required flow at between 20 and 30 psi. In this case, the outlet pipe becomes more like a nozzle. Table 68 shows that an orifice of 2" diameter supports 1MW of steam at 25psi internal pressure when venting to atmosphere.
Your simulation shows a higher flow rate than table 68 suggests. As posted previously equation 44 from the book chapter suggests that a flow of 1MW worth of steam through 48inches of 2" pipe would drop the pressure by ~2.5psi. Your simulation appears to show a different result but the source of the difference is not apparent to me.
I am wondering why there is a difference.
Your simulation shows a higher flow rate than table 68 suggests.
The simulation only shows velocity, not flow rate (that was a boundary condition set to 0.385 kg s-1 @ 390k)
Part of the flow profile in the simulation shows sonic conditions at the prescribed mass flow of 0.385 kg s-1. This will limit the mass flow rate to an amount dependent on pressure or as you put it, "a nozzle". This is not a good thing.
Yes table 66 shows that a 2" pipe is totally insufficient for this reactor.
I agree, and using a 2 inch pipe as a mass flow limiting device (if he designed it that way) doesn't make sense to me.
I hope he has appropriate over pressure safety before the pipe.
If it is as much as 4" then table 66 shows that it can support the required flow at between 20 and 30 psi.
If he is running or planning to run 30 psi operating pressure, I wonder what he calculated for a safety factor on the square pressure vessels
The simulation only shows velocity, not flow rate (that was a boundary condition set to 0.385 kg s-1 @ 390k)
Part of the flow profile in the simulation shows sonic conditions at the prescribed mass flow of 0.385 kg s-1. This will limit the mass flow rate to an amount dependent on pressure or as you put it, "a nozzle". This is not a good thing.
Why is this a bad method of maintaining back pressure withing the system?
If he is running or planning to run 30 psi operating pressure, I wonder what he calculated for a safety factor on the square pressure vessels
In the most recent test the pressure inside the reactor at 120C, if the steam was in equilibrium with liquid water, would have been 28psi. Of course, a slow leak of 2kg/hr was observed dripping from the device.
AcesHigh wrote:long time I dont follow the Rossi´s LERN device...
so, after all these months... any veredict? Is the effect real? Or was it a scam?
From my perspective:
1) The likelihood that it is a deliberate fraud is getting down to almost zero%.
2) The likelihood that Rossi suffers a serious personality issue is getting up to level of certainty.
3) The likelihood of some degree of delusion is getting up as well mostly due to Rossi's character and kind of people he may involve.
4) The likelihood of thermal output above breakeven is getting up as well (the most important bullet)
5) It becomes apparent that E-cat is far away from a reliably controlled end-user product even the inherited reproducibility issue of CF is spectacularly improved.
6) The development of LENR is getting hot...
Crawdaddy wrote:Why is this a bad method of maintaining back pressure withing the system?
No relief that I can see, if the pressure bumps there is no pressure control.
In the most recent test the pressure inside the reactor at 120C, if the steam was in equilibrium with liquid water, would have been 28psi. Of course, a slow leak of 2kg/hr was observed dripping from the device.
With an output restriction the pressure is now dependant on the power produced.
stefanbanev wrote:
1) The likelihood that it is a deliberate fraud is getting down to almost zero%.
2) The likelihood that Rossi suffers a serious personality issue is getting up to level of certainty.
1) "the likelihood of a deliberate fraud" [by Rossi as the brain behind it] "is getting down to almost zero"
2) How dare ya?! This is a physics forum! Joseph will eat your head in a moment.
I re-ran the simulation with a pressure goal and it appears that for 0.385kg s-1, the pressure differential across a the pipe is only 18000Pa. The flow has sonic regions but unless the power level skyrockets, the restriction may not cause a problem.
At .770kg s-1 (2MW worth of steam) the back pressure is 81733Pa, about 12 PSIg.
So there you have it, go Rossi go.
btw: This is only for a 2 foot pipe (0 roughness)
Sonic flow through an L may have some interesting flow patterns and pressures.
I don't see why he needs any back pressure, just boil it off, much safer.
The dimensions of the valve are 2,5", and the dimension of the line are realistically 2" as in standard practice.
It is not important what you have before this line, it can be an 80" pipeline or a 200" diameter pressure vessel. Where your calculations must start in this layout is from the lowest section where all the flow has to pass.
As for making the calculation, I have given you a rough calculation in the previous pages. All what you need is there.
I can add to those indications what are the general guidelines for maximum allowed Saturated Steam speed in a pipeline is 25 to 35 m/s.
Another quick calculation can show that to keep a 0,5 bar maximum pressure inside the line system you need to have a 125 mm output pipeline with a nominal flow speed of 25-35 m/s.
More than that pressure and all those nice square e-Cat into the container will start to blow like popcorns in a kettle.
Giorgio wrote:Another quick calculation can show that to keep a 0,5 bar maximum pressure inside the line system you need to have a 125 mm output pipeline with a nominal flow speed of 25-35 m/s.
More than that pressure and all those nice square e-Cat into the container will start to blow like popcorns in a kettle.
I re-ran the simulation with a pressure goal and it appears that for 0.385kg s-1, the pressure differential across a the pipe is only 18000Pa. The flow has sonic regions but unless the power level skyrockets, the restriction may not cause a problem.
At .770kg s-1 (2MW worth of steam) the back pressure is 81733Pa, about 12 PSIg.
So there you have it, go Rossi go.
btw: This is only for a 2 foot pipe (0 roughness)
Sonic flow through an L may have some interesting flow patterns and pressures.
I don't see why he needs any back pressure, just boil it off, much safer.
Very interesting! Thanks for taking the time to run some simulations.
I agree that the device is very poorly designed, but as long as its function is not ruled out by the well known principles of steam flow, then at least it probably won't blow up.
The dimensions of the valve are 2,5", and the dimension of the line are realistically 2" as in standard practice.
It is not important what you have before this line, it can be an 80" pipeline or a 200" diameter pressure vessel. Where your calculations must start in this layout is from the lowest section where all the flow has to pass.
As for making the calculation, I have given you a rough calculation in the previous pages. All what you need is there.
I can add to those indications what are the general guidelines for maximum allowed Saturated Steam speed in a pipeline is 25 to 35 m/s.
Another quick calculation can show that to keep a 0,5 bar maximum pressure inside the line system you need to have a 125 mm output pipeline with a nominal flow speed of 25-35 m/s.
More than that pressure and all those nice square e-Cat into the container will start to blow like popcorns in a kettle.
As your rough calculations shows the pressure in the 2 foot pipeline cannot be 1.5 bar, and the flow rate exceeds the general guidelines for pipelines (which are generally very much longer than 2 feet).
The exact back pressure that will develop as a result of this small outlet diameter is not shown in your rough calculation. Simulation data provided by Sparkyy007 and steam table calculations from a book chapter link provided by parallel show that the back pressure should not rise high enough to blow up the components (even if they perform as claimed).
On what basis do you make the claim that the back pressure will be catastrophic?
Giorgio is right.
The simulation was only for 2 feet of pipe to reduce calculation time of the simulation. I am not implying only 2 feet of pipe is used in Rossi's unit.
Joints and angles will also affect the back pressure.
The recommended vel is 80ft s-1 for steam flow, not sonic flow.
The reactor shape IMHO will over stress the steel at the corners (bending the joints) with as little as 3-5 PSI differential pressure.
According to Matts report the size is 50x60x35
The force with only 5 psi back pressure (34.7kPa) on the top or bottom plate is over a ton ( on a diaphram with L joints! ).
Last edited by sparkyy0007 on Wed Oct 19, 2011 4:24 pm, edited 1 time in total.
Giorgio is right.
The simulation was only for 2 feet of pipe to reduce calculation time of the simulation. I am not implying only 2 feet of pipe is used in Rossi's unit.
Joints and angles will also affect the back pressure.
The recommended vel is 80ft s-1 for steam flow, not sonic flow.
The reactor shape IMHO will over stress the steel at the corners (bending the joints) with as little as 3-5 PSI differential pressure.
In an effort to foster agreement: do you concur that the thing will not explode if the following assumptions are true:
1. the internal steam manifold is 4" or greater (from the video)
2. the individual e-cat elements of the device can withstand pressures consistent with steam at 125C in equilibrium with water (between 2 and 3 atmospheres as demonstrated in the test earlier this month).
3. the back pressure is consistent with your simulated data and the information from the book chapter.
If any or all of the above points are false then the device is not feasible on a first principle basis.
I agree with you that the device does not follow recommended guidelines for steam pipelines, but I fail to see how that means that it is likely to fail based on the framework we previously discussed.
Last edited by Crawdaddy on Wed Oct 19, 2011 4:41 pm, edited 1 time in total.
Giorgio is right.
The simulation was only for 2 feet of pipe to reduce calculation time of the simulation. I am not implying only 2 feet of pipe is used in Rossi's unit.
Joints and angles will also affect the back pressure.
The recommended vel is 80ft s-1 for steam flow, not sonic flow.
The reactor shape IMHO will over stress the steel at the corners (bending the joints) with as little as 3-5 PSI differential pressure.
In an effort to foster agreement do you concur that the thing will not explode if the following assumptions are true:
1. the internal steam manifold is 4" or greater (from the video)
2. the individual e-cat elements of the device can withstand pressures consistent with steam at 125C in equilibrium with water (between 2 and 3 atmospheres as demonstrated in the test earlier this month).
3. the back pressure is consistent with your simulated data and the information from the book chapter.
If points any or all of the above points are false then the device is not feasible on a first principle basis.
I agree with you that the device does not follow recommended guidelines for steam pipelines, but I fail to see how that means that it is likely to fail based on the framework we previously discussed.
Due to the geometry of the reactor container, every change in pressure will change the shape of the container. These forces will concentrate at the joints. This will work harden the joints and eventually cause them to fail.
Will they fail during the short test, I cannot say, it depends on the frequency and magnitude of pressure fluctuations as well as maximum pressure.
Properly designed pressure vessels do not significantly change shape when used within their design limits.
Due to the geometry of the reactor container, every change in pressure will change the shape of the container. These forces will concentrate at the joints. This will work harden the joints and eventually cause them to fail.
Will they fail during the short test, I cannot say, it depends on the frequency and magnitude of pressure fluctuations as well as maximum pressure.
I completely agree that the design is retarded. As evidenced by the fact that the element tested in early October had a water leak that developed as the internal temperature rose to 120C and above (presumably a pressure of around 2 atm).
Based on the corrosion of the lid observed when the device was opened the element has seen some degree of use.
Can we agree then that if all the ecat elements perform in a manner similar to what was observed on october 7 (again assuming the test was legitimate) and the geometry of the greater steam manifold and 2" exit pipeline conforms to the assumptions listed in my previous post that there will not be an explosion if 1MW of steam is produced on october 28?
I agree that if the corners of the individual elements cannot withstand greater than 2 atmospheres of pressure then the experiment will likely end catastrophically.
We have a boiler and steam plant that everyone here would agree is of unorthodox design. Moreover, at least some folks here assert the design is actually unsafe.
...
I don't know what the regs are like in Italy, but in the US any steam plant (or even a household water heater) has minimal safety features that must be in place, and it also has to be inspected and certified for operation by the local authorities; some sort of local inspector.
1) Has Rossi applied for and/or obtained a certification for operation of his steam plant?
2) What was the inspector's reaction to Rossi's design and safety features (or lack thereof)?
3) What was the inspector's reaction when informed that the heat source was a new and heretofore unknown LENR process (i.e., this is an unlicensed nuclear reactor)?
4) What was the inspector's reaction when informed that the steam discharge from this unlicensed nuclear reactor would be fed down a drain and into the sanitary sewer system on its way to the local waste water treatment plant (presuming that Rossi continues the same effluent discharge method as all previous demos)?
Remember that the Petrodragon scam didn't end with Rossi being charged with fraud; he was shut down because his device generated tons of toxic waste that the local officials didn't want polluting their town.
Joseph will eat your head in a moment.