Chinese Hypersonic Developments (HGVs/HCMs)

GreenestGDP said:

China Hypersonic Facilities
#2
High-frequency Induced Plasma Wind Tunnel

Plasma Generator
Temperature Range: 3000 --- 10,000 Kelvin
= 2726.85 --- 9726.85 Celsius

Courtesy of: cirr ~ Pakistan Defense Forum





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I have googled info regarding the best NASA Hypersonic wind tunnel.
The best is located in Langley, Virginia.

What I found are weird ... ...

1) Information on the net about NASA Hypersonic wind tunnel is almost zero.
If any is very cryptic.

China Hypersonic Facilities seem to be much more open and transparent,
and offer much more detailed info.





**) What I found below is even more weird, because NASA had started the hypersonic research since around 1955. Thus, NASA suppose to have a huge lead in technology compare to China.


2) After my digging around, the last upgrade on NASA Hypersonic wind tunnel was done in 1988. NASA highest speed is mach 10, and with Nozzle diameter size = 78.74 cm

China mach 10 Hypersonic wind tunnel have Nozzles diameter size = 120 cm
China mach 10 nozzle diameter is bigger by 52%.
That is quite a margin.


3) NASA highest Temperature wind tunnel has a maximum = 1893.52 Celsius
China highest Temperature wind tunnel has a maximum = 9726.85 Celsius


I could be mistaken ... ...
To those who are much more knowledgeable than me,
please feel free to enlighten me.

Thank you so much in advance.

Below is some data from NASA Langley Hypersonic wind tunnel

GreenestGDP said:

I could be mistaken ... ...
To those who are much more knowledgeable than me,
please feel free to enlighten me.

Thank you so much in advance.

Click to expand...

Like I posted before air flow simulation can be done through computer simulation so physical air tunneling had gone the way of the dodos.
As for plasma heated wind tunnel it depends on the amount of plasma within the containment field. You can hyper heat plasma but it can be done by thinning out the amount of plasma on the other hand within a rich plasma environment to heat it up it becomes immensely difficult because you have more material to heat up.

SamuraiBlue said:

Like I posted before air flow simulation can be done through computer simulation so physical air tunneling had gone the way of the dodos.
As for plasma heated wind tunnel it depends on the amount of plasma within the containment field. You can hyper heat plasma but it can be done by thinning out the amount of plasma on the other hand within a rich plasma environment to heat it up it becomes immensely difficult because you have more material to heat up.

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Firstly, thank you for sharing your feedback.
I am not an expert. I am just a pedestrian military fanboy.

Let's break these down into 2 separate sections.
Let's say we plan to build a physical prototype of a hypersonic UAV, with specific aerodynamic designs ( design type = WJMG-1 , WJMG-2 , WJMG-3 ).


You are stating that ... ...

#A) Computer Software Simulation * Obliterate * Physical Wind Tunneling
Thus, NASA has abandoned Physical Wind Tunnels, and replaced the Physical Wind Tunnels experiments with Computer Software Generated Simulations.

Just to confirm, this is what you are stating. -- right ?

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Simulation means most of the variable is known and understood.
My questions are : ... ...

1) What is the maximum # of ( unknown variables ) that can be handle by Computer Software Generated Simulation ?

2) In this case ( build a physical prototype of a hypersonic UAV ), what is / are being simulated ?

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3) Please explain a bit more on Plasma heated Wind Tunnel,
and why NASA Highest Temperature Wind Tunnel can only get up to 1893.52 Celsius ?
It means 7833 degree Celsius smaller than * PRC Plasma Heated Wind Tunnel.

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If I misunderstood you, please feel free to correct me ... ...

SamuraiBlue said:

Like I posted before air flow simulation can be done through computer simulation so physical air tunneling had gone the way of the dodos.
As for plasma heated wind tunnel it depends on the amount of plasma within the containment field. You can hyper heat plasma but it can be done by thinning out the amount of plasma on the other hand within a rich plasma environment to heat it up it becomes immensely difficult because you have more material to heat up.

Click to expand...

You mean like how Japan their ATD-X to France for wind tunnel testing in 2006?

GreenestGDP said:

Firstly, thank you for sharing your feedback.
I am not an expert. I am just a pedestrian military fanboy.

Let's break these down into 2 separate sections.
Let's say we plan to build a physical prototype of a hypersonic UAV, with specific aerodynamic designs ( design type = WJMG-1 , WJMG-2 , WJMG-3 ).


You are stating that ... ...

#A) Computer Software Simulation * Obliterate * Physical Wind Tunneling
Thus, NASA has abandoned Physical Wind Tunnels, and replaced the Physical Wind Tunnels experiments with Computer Software Generated Simulations.

Just to confirm, this is what you are stating. -- right ?

----------------------------------------------------------------------

Simulation means most of the variable is known and understood.
My questions are : ... ...

1) What is the maximum # of ( unknown variables ) that can be handle by Computer Software Generated Simulation ?

Click to expand...

What do you mean by unknown variables are you talking about?

GreenestGDP said:

2) In this case ( build a physical prototype of a hypersonic UAV ), what is / are being simulated ?

Click to expand...

Don't ask me I really do not know.
Basically wind tunnel testing is to optimize air flow dynamics of design under various conditions. We know very well about
A wind tunnel test are done to confirm fluid mechanics under various conditions collecting data to further optimize computer simulations.

GreenestGDP said:

3) Please explain a bit more on Plasma heated Wind Tunnel,
and why NASA Highest Temperature Wind Tunnel can only get up to 1893.52 Celsius ?
It means 7833 degree Celsius smaller than * PRC Plasma Heated Wind Tunnel.

Click to expand...

Heat of plasma is the amount of movement of atoms. With less amount of atoms within the chamber it becomes easier to excite thus higher temperature of plasma.
In other words the difference in temperature is due to difference in conditions.

As for ATD-X, I do not recall doing a wind tunnel test in France. I do remember TRDI doing a RCS test with a wind tunnel model though.

SamuraiBlue said:

Like I posted before air flow simulation can be done through computer simulation so physical air tunneling had gone the way of the dodos.
.......................

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A claim like this can only be made by those who don't know how scientific experiments are done or lack the fund and techs to build advanced wind tunnel.
Given the resources, scientists, in any fields, will want to experiment in as close to real world conditions as possible. And wind tunnels are orders of magnitude closer to real world than computer simulations.

Computers can only 'replace' wind tunnels in mature fields like in lower air speed. In leading edge fields like hypersonic speed, how can you program your computer simulations when little of the variables are known ? And these variables can only be observed in wind tunnels.

It's a giant leap of faith to base your design in a new field like hypersonic speed on computer simulations as shown by US lack of success here and being overtaken by China who have access to better wind tunnel and supercomputers.

What kind of variable are you talking about and how are you going to see them when the amount of time you can reach the high mach numbers within a wind tunnel is fraction of a second?

SamuraiBlue said:

What kind of variable are you talking about and how are you going to see them when the amount of time you can reach the high mach numbers within a wind tunnel is fraction of a second?

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Various sensors collecting large volumes of data in a very short window of time. You will still need computers, and that data is valuable for building simulations, but you still need to do the experiment to collect the data. You can't magic data out of nowhere, and what you're doing isn't a simulation. No ones denying that computers are immensely important in the research and experimentation process for these extreme conditions, but that doesn't mean you can just forgo physical data collection and observation.

As I had stated before fluid mechanics is a well known and defined science. The variables you talk about is nothing that can't be calculated. Also on a 50cm physical model cannot pick up in millimeter grid detail a computer generated simulation can provide. You also cannot gain any knowledge during a turn with a physical wind tunnel at high mach speed. Wind sheer tension can also not be measured precisely in a physical model.
Like I said you don't do a physical test on a actual model these days to optimize aerodynamics of a plane.