The military-industrial scientific research system of the academic master.

Chang Haonan's report may seem a bit abrupt, but it actually hits a very delicate point in time.

In fact, China started research on hypersonics very early.

In the mid-50s, when China had not yet successfully launched its first missile, two predecessors, Qian Xuesen and Guo Yonghuai, formed a "shock wave wind tunnel" research group at the Institute of Mechanical Engineering of the Chinese Academy of Sciences and began to plan hypersonic technology research from a strategic level.

You have to know that at that time, even the United States and the Soviet Union had not yet determined from an engineering perspective what specific technical means could be used to achieve hypersonic flight.

However, relevant departments and leaders realized the great significance of this research, and squeezed out some resources under quite difficult conditions to support the construction of the JF4 straight-through and JF4A reflection shock wave wind tunnels.

Finally, in 1969, they achieved great success by creating the JF8 cold hypersonic wind tunnel, which represented the world's top level at that time.

The operating range is up to Mach 15.

However, traditional aerodynamic research is generally based on the principle of "flow state simulation", that is, based on a reduced aircraft model, the experimental airflow is required to meet certain flow phase parameters, such as the similarity of Mach number and Reynolds number.

Hypersonic research focuses more on "reproduction of flight conditions", requiring that the main parameters of the experimental airflow, such as velocity, static temperature, static pressure, medium composition, and characteristic scale, be the same as actual flight conditions.

For example, under flight conditions of Mach number 7, even if traditional wind tunnels can simulate airflow at this speed, the total temperature of the gas under experimental conditions is only 648 K, far less than the 2500-3000 K under actual flight conditions, and is completely unable to reproduce the core physical phenomena of hypersonic flow.

Therefore, wind tunnels like the JF8 still have significant limitations.

In order to truly conduct practical hypersonic research, it is necessary to further increase the total operating temperature of the wind tunnel while ensuring the air flow speed.

To achieve this goal, Europe, Japan and the United States have independently developed two technical routes: free piston drive and heated light gas drive.

However, both solutions go to the other extreme, that is, one-sided emphasis on the total working temperature, but in order to expand the experimental flow field and extend the experimental time, it will cost a huge amount of money.

This was totally unacceptable to China in the last century.

Fortunately, domestic scholars found the detonation drive solution, which seemed to have very low feasibility. With the support of the 863 Program, they successfully carried out preliminary technical demonstration through the JF1998 wind tunnel built in 10.

The year 2005 happens to be the next critical node in the selection of the ultra-high-speed wind tunnel route.

Therefore, although he did not receive immediate feedback after submitting the report, Chang Haonan was not in a hurry.

Instead, he quickly focused his attention on the theoretical aspects of solving the high-dimensional Chapman-Jouguet combustion equation...

……

Sure enough, about a week later, Chang Haonan received a call from Li Zhongyi.

"Hello, Director Li."

He knew exactly the purpose of the other party's call, so even his tone sounded confident.

But it turned out that Chang Haonan had underestimated the influence of his own handwritten report...

Li Zhongyi on the other end of the phone didn't even have time to say hello:

"Academician Chang, the superiors would like to invite you to give a report at Jingxi Hotel next Monday. I want to ask if it is convenient for you to arrange it?"

In one sentence, Chang Haonan almost had a power outage -

Words like invite and ask are obviously polite.

Li Zhongyi’s superior, what a joke.

Can you still say it's inconvenient?

So the key is not here, but...

"Report?"

"In Jingxi Hotel?"

For a moment, Chang Haonan found it a little difficult to combine these two nouns together.

In actual operation, the Jingxi Hotel is under the jurisdiction of the General Staff Management and Support Department. Its level is almost the same as that of the Great Hall of the People, and its secrecy is even greater.

Even he was only lucky enough to attend a one-day meeting after the 2001 attacks.

The problem is that that place is generally used for decision making, not academic discussion...

"Yes, Jingxi Hotel."

Li Zhongyi emphasized and confirmed again:

"The report you submitted is very timely. The General Armament Department has some questions about the hypersonic test plan proposed by the Institute of Mechanics and China Aerospace Science and Industry Corporation... There are also some disputes among them, so we would like to hear your opinions."

Chang Haonan knew that he was stuck in time.

But I didn’t expect it to be so accurate.

The Institute of Mechanics is the research and development institution for all the above-mentioned JF series wind tunnels.

As for the Science and Industry Group, after the China Aerospace Corporation was split into two, it became the unit specifically responsible for sending people to heaven.

At the turn of the century a few years ago, they obtained some "cold" program information based on the development of the 5V28 missile from the Baranov Central Institute of Aviation Engines.

However, at least on the original timeline, there is no evidence that these materials have a direct technical connection with the hypersonic weapons that China eventually put into service.

"So will both departments send people together?"

He asked as he thought quickly.

"Yes, but not together."

Li Zhongyi replied:

"The superior hopes to hear opinions from all parties separately, so as to avoid your views affecting each other..."

This reply made Chang Haonan feel nervous.

Obviously, this is not just a discussion.

It is a fairly high-level decision-making reference.

"Then I'll prepare."

Chang Haonan said this and looked at the computer screen.

Inside the folder, there were more than a dozen documents that had already been sorted out lying quietly.

Li Zhongyi on the other end of the phone hesitated for a moment, but finally gave an instruction:

"Academician Chang, although there are some professionals in this report, they are mainly leaders, so try to shorten the theoretical part... especially the length of the theoretical mathematics part. I am worried that everyone will not be able to accept it..."

Chang Haonan was full of black lines:

"Don't worry, I know what's going on..."

hang up the phone.

That being said, the content he had prepared certainly could not be uploaded as is.

The decision-makers do not care, nor do they need to care, about how the detonation equation gives a global solution, or how the high-precision hybrid format is applied in gas phase detonation calculations.

So the focus should be on -

Chang Haonan reopened a Word document and typed a heading on the first page:

"On the Necessity and Characteristics of Hypersonic Vehicle Design Layout Optimization".

……

The information is still the same, it just needs to be reorganized.

As required, Chang Haonan arrived at the conference building of Jingxi Hotel early on the day of the report.

What was somewhat beyond his expectations was that the place he was led to after the staff arrived was actually a small meeting room.

Even including the seats that were obviously added temporarily, there were only about twenty seats.

As for the participants who arrived shortly afterwards, there were even more of them than the last time the high-standard farmland construction project was decided.

Among them are bigwigs in the military's decision-making level, such as Qiao Chenqing and Chen Bingde.

Even the two of them couldn't sit in the two seats in the middle...

Seeing Chang Haonan preparing on the podium, Qiao Chenqing, who was quite familiar with him, originally wanted to go up and say hello.

But before he could stand up, he heard the report starting over the loudspeaker.

Almost at the same time, two old men in unranked military coats appeared outside the door...

"Dear leaders, I am very honored to be here today to report on the development of our country's hypersonic aircraft and some of the latest research progress..."

Even Chang Haonan felt unprecedentedly nervous when faced with this situation.

Even the speaking speed became faster.

"my country started its basic research on hypersonic theory very early, especially since the late 1980s. Through numerical simulation and small-scale experiments, we have conducted exploratory research in the fields of flow field morphology of hydrogen fuel combustion, basic concepts of scramjet engines, guidance and control rate of hypersonic aircraft, etc. The gap with developed countries lies mainly in aerodynamic layout design and flight testing..."

"Although my personal knowledge of numerical simulation is still limited, from some past research, I know that hypersonic aircraft are different from conventional subsonic, transonic and hyposonic aircraft. There are three characteristics, or difficulties, in the design optimization of hypersonic aircraft."

"First, the fuselage propulsion integration caused by the special aerodynamic layout. Since hypersonic aircraft generally use scramjet or combined propulsion engines, they have high requirements for working conditions and the power they generate is not abundant. Therefore, the design process must be carried out around the requirements of the engine, so that the hypersonic aircraft fuselage and scramjet engine present a highly integrated feature..."

“Second, multi-objective optimization design is complex…”

"The third one is derived from the second one, which is a global optimization algorithm that is suitable for large-scale complex multi-objective problems... Fortunately, thanks to the support and help from my superiors, my research team has achieved certain results in this regard, but it still needs a lot of data support from high-fidelity experiments..."

As the content moved into areas that he became more and more familiar with, Chang Haonan gradually got into the state.

When he said this, he also took a special look at the state of the audience below.

Fortunately, no one expressed any negative feedback.

It just seems a bit bland relatively speaking.

However, Chang Haonan had already prepared a blockbuster explosion point below.

"Based on current research, the aerodynamic layout of hypersonic vehicles can be roughly divided into five categories, corresponding to two different power forms and three different applicable environments."

He said as he clicked the mouse lightly.

Then, a three-dimensional diagram appeared on the screen.

Although Chang Haonan's voice was the only one heard in the meeting room, more than a dozen leaders adjusted their sitting positions almost simultaneously when the PPT page was turned.

The look he cast towards Chang Haonan also carried some curiosity——

Weren’t we just talking about a lot of difficult points?

Why are there suddenly five layouts?