Chapter 1172 Five Configurations

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

In fact, China’s research on hypersonics started very early.

In the mid-1950s, before China had even successfully launched its first missile, two seniors, Qian Xuesen and Guo Yonghuai, formed a "shock wind tunnel" research team at the Institute of Mechanical Engineering, Chinese Academy of Sciences, and began to plan hypersonic speeds from a strategic level. technology research.

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

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

Finally, in 1969, it became a blockbuster with the creation of the JF8 cold hypersonic wind tunnel, which represented the world's top level at that time.

Operating range is up to Mach 15.

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

Hypersonic research pays more attention to the "reproduction of flight conditions", which requires the main parameters of the experimental airflow, such as speed, static temperature, static pressure, medium composition, and characteristic scale, to be the same as the actual flight conditions.

For example, under flight conditions of Mach number 7, even if a traditional wind tunnel can simulate airflow at this speed, the total gas temperature under experimental conditions is only 648 K, which is far less than the 2500-3000 K under actual flight conditions. It is impossible to Reproduce the core physical phenomena of hypersonic flow.

Therefore, wind tunnels like JF8 still have great limitations.

In order to truly carry out practical hypersonic research, it is necessary to further increase the total working temperature of the wind tunnel while ensuring the airflow speed.

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

However, these two solutions have gone to the other extreme, that is, one-sided emphasis on the total working temperature, but if you want to expand the experimental flow field and extend the experimental time, you need to pay a huge cost.

It was completely unacceptable to China in the last century.

Fortunately, domestic scholars have found the seemingly low-feasibility solution of detonation drive, and with the support of the 863 Project, they successfully conducted a preliminary technical demonstration through the JF10 wind tunnel built in 1998.

This meeting in 2005 happens to be the next key node in the selection of ultra-high-speed wind tunnel routes.

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

Instead, he quickly focused on the theoretical level 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."

It can be said that he knew the purpose of the other party's call, so even his tone was confident.

But it turns out that Chang Haonan still 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, your superiors want to invite you to the Jingxi Hotel to give a report next Monday. Let me ask if your arrangement is convenient?"

In one sentence, Chang Haonan almost suffered a power outage——

Words such as invitations and inquiries are obviously polite.

Li Zhongyi's superior, what a joke.

Can it be said that it is inconvenient?

So the key is not here, but...

"Report?"

"In Jingxi Hotel?"

Chang Haonan had a hard time combining these two terms.

In actual operation, the Jingxi Hotel is affiliated to the General Staff Management and Security Department. Its level is almost the same as that of the Great Hall, and its secrecy is even worse.

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

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

"Yes, Jingxi Hotel."

Li Zhongyi added emphasis and confirmed again:

"The report you submitted can be said to be very timely. The General Armament Department happens to have some questions about the hypersonic test plan proposed by the Institute of Mechanics and the Aerospace Science and Industry Corporation...including some internal disputes within themselves, so I want to hear it comprehensively. What do you think?"

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 R&D institution for all the above-mentioned JF series wind tunnels.

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

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

However, at least in the original timeline, there is no evidence that this information has a direct technical connection with the hypersonic weapons that China finally put into service.

"So will their two departments also send people to go together?"

he asked, thinking quickly.

"Yes, but not together."

Li Zhongyi replied:

"The superior hopes to listen to the opinions of each side separately to prevent your opinions from affecting each other..."

This reply made Chang Haonan feel nervous.

Obviously, this is not a simple discussion.

Rather, it is a rather high-level decision-making reference.

"Then I'll prepare."

Chang Haonan said and looked at the computer screen.

Inside the folder, there were more than a dozen related information that had been sorted out quietly.

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

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

Chang Haonan's head is full of black lines:

"Don't worry, I know it..."

Hang up.

That's what he said, but the content he originally prepared cannot be uploaded as it is.

The decision-making layer does not care or need to care about how the detonation equation provides a global solution, and how the high-precision hybrid format is applied in gas-phase detonation calculations.

So the focus should be -

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

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

…

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

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

What was somewhat beyond his expectation was that after being guided by the staff, he arrived at a small conference room.

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

As for the number of participants who arrived one after another, it was even better than the last time the high-standard farmland construction project was finalized.

They also include Qiao Chenqing, Chen Bingde and other military decision-making leaders.

Even the two of them cannot sit in the two middle seats...

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

But before he could get up, he heard the sound of a report being prepared to start coming from the loudspeaker.

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

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

Even Chang Haonan felt nervous for the first time when faced with the situation in front of him.

Even the speed of speaking has become much faster.

"Our country's basic research on hypersonic theory started very early. Especially since the late 1980s, through numerical simulations and small-scale experiments, the flow field shape of hydrogen fuel combustion, the basic concept of scramjets, and the design of hypersonic aircraft have been studied Exploratory research has been conducted in areas such as guidance and control rate, and the gap with the first-mover countries mainly lies in aerodynamic layout design and flight testing..."

"Although my personal knowledge of numerical simulation is still limited, judging from some research conducted in the past, hypersonic aircraft are different from conventional sub-, trans-, and hyposonic aircraft. There are three characteristics in its design optimization...or in other words: difficulty."

“The first is the integration of airframe propulsion caused by the special aerodynamic layout. Since hypersonic aircraft generally use scramjet or combined propulsion engines, they have very high requirements on working conditions and the power generated is not abundant. Therefore, the design process must revolve around the requirements of the engine. And the expansion makes the hypersonic aircraft fuselage and scramjet engine appear highly integrated..."

"Second, multi-objective optimization design is complicated..."

"The third one is derived from the second one, a global optimization algorithm adapted to large-scale complex multi-objective problems... Fortunately, thanks to the support and help provided by superiors, my research group has achieved certain results in this aspect , but it still needs data support from a large number of high-reduction experiments..."

As the content came to areas that he was becoming more and more familiar with, Chang Haonan also gradually entered the state.

When he said this, he also specially observed the state of the audience below.

Fortunately, no one showed any negative feedback.

It just seems a bit bland relatively speaking.

However, Chang Haonan has already prepared a major explosive point below.

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

He said with a slight click of the mouse.

Immediately afterwards, a three-dimensional diagram appeared on the curtain.

Although there was still only Chang Haonan's voice in the venue, at the moment when the PPT page was turned, more than a dozen leaders adjusted their sitting postures almost simultaneously.

The look he cast towards Chang Haonan also brought with it some curiosity——

Didn’t you just talk about a lot of difficulties?

Why are there suddenly five layouts?