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Author Topic: LEM ECS Developement  (Read 1328 times)
jalexb88
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« on: August 14, 2017, 02:35:46 PM »

I'm starting a new thread for discussion of the LEM environmental control system development. Up until now this is an area that has been lacking in NASSP. I have taken a first step and created some preliminary ECS panel and switch bitmaps for the LEM ECS. Note however that these are just the bitmaps and for now they are not yet integrated in code. Coding is not really my area of expertise so I would like to invite anyone who wishes to do so to take care of that aspect. I can coordinate with whoever does it and update my panel graphics if any adjustments are needed.

Here is a screenshot: (the actual bitmap is much larger and higher quality at 2304 x 1296 pixels)



Please carry on with any LEM ECS discussions  Happy
« Last Edit: August 14, 2017, 02:39:42 PM by jalexb88 » Logged
Thymo
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« Reply #1 on: August 14, 2017, 06:31:17 PM »

I figured I'd give it a shot to load this into the LEM.
After some time messing with all the things needed to load it in and register it with Orbiter I got it to work. Very Happy

It's still a bit on the large side and none of the switches are in yet but it's a start.

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Thymo
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« Reply #2 on: August 19, 2017, 06:03:13 PM »

The panel has been pushed. It's still without switches but at least you'll have something to look at.
I'm currently working on adding all the clickable switches.
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Thymo
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« Reply #3 on: October 06, 2017, 10:32:19 AM »

First pass has been committed to my fork. Will need some testing and then some issues with a couple of rotaries need to be resolved.
If all goes well it should be finished this weekend.
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Thymo
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« Reply #4 on: November 26, 2017, 12:17:07 PM »

Pull request has been made. There still remain some issues with a couple of controls but the majority is working.
I've made a quick overview here: https://github.com/dseagrav/NASSP/pull/214

Now the real work begins.
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rcflyinghokie
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« Reply #5 on: December 24, 2017, 10:30:59 PM »

Just a quick update on this, everyone has been putting a lot of effort into the LM ECS in a development branch and I am happy to say it is at a point where only fine tuning is necessary and should soon be merged into the main repository.  As others have mentioned before, the conversation/discussion of this development has been happening on a daily basis in the NASSP IRC channel and not here, which is why this particular post has been dormant.  I am certain someone will make an announcement when this is done as it will impart many more challenges and of course require a lot of beta testing to make sure we have things working the way they ought to be. 
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indy91
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« Reply #6 on: January 27, 2018, 07:33:38 AM »

There is a fairly severe bug with the LM ECS currently. During normal LM pressurization the pressure and energy state of most tanks in the LM suddenly becomes NaN. rcflyinghokie and I have been try to find the cause of this, but it is a fairly tricky bug.

What I have been able to find is some problems with the secondary glycol loop. The flow between the different tanks works as follows:

SECGLYCOLACCUMULATOR -> SECGLYCOLLOOP1 -> SECASCBATCOOLING -> SECGLYCOLLOOP2 -> SECEVAPINLET -> SECEVAPOUTLET -> SECGLYCOLACCUMULATOR

All of these are connected by normal pipes, only SECGLYCOLACCUMULATOR and SECGLYCOLLOOP1 are connected by a pump, with pumps working basically like pipes with added pressure. What seems to happen is that all the mass in the loop accumulates in SECGLYCOLACCUMULATOR, while SECGLYCOLLOOP1 and SECASCBATCOOLING becoming close to empty over time. And then when using time acceleration things become unstable and those two tanks suddenly have an energy state of 0 with a mass greater than 0, which can't be good. I am not 100% sure the NaNs originate here, but it seems likely. After reaching energy state 0 it still takes a while for everything to go bad though.

One potential issue is with how our pumps work. They don't let anything through when they are off. So nothing can flow from SECGLYCOLACCUMULATOR to SECGLYCOLLOOP1 in the normal state after LM ejection from the S-IVB, which has the secondary glycol pump in off. But it seems to me that the glycol loops in the CSM work similarly. And you can also see a little bit of accumulation in the tank connected to the pumps IN valve in the CSM glycol loops, but not as severe as in the LM. So in addition to it not being a closed loop, something must force a mass flow from SECGLYCOLLOOP1 all the way through SECGLYCOLACCUMULATOR. Maybe just some instabilities or the added heat or so.

This is what I have found out so far. I hope it helps a little bit, RC.
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