Chapter 1169 Next Step, Hypersonic Speed or Variable Cycle?
Integrating the entire engine into the nacelle is actually a relatively complicated task.
However, the turbofan 20 is still undergoing major component testing, so the only things that will be installed soon are the fan and the high-pressure compressor.
Even so, it took the two teams of Qin Fei and Haofa several hours to complete the assembly work before the sun set that day.
In fact, for a brand new engine-pod assembly, this efficiency cannot be considered low.
But after all, Chang Haonan was still thinking about fully automatic assembly in the morning, so his vision and requirements are naturally different now.
However, the meal must be eaten one bite at a time.
The top priority is to verify the integration level of the nacelle and engine booster structure.
Generally speaking, large aircraft such as transport aircraft and passenger aircraft have four typical flight states, namely the first take-off stage, the second take-off stage, the climbing stage and the high-altitude cruising stage.
Naturally, there is no such thing as a large wind tunnel or a high-altitude simulation test bed in the assembly workshop, so the engine performance under the latter two conditions can only be determined when the complete machine is tested on the ground in the future.
Fortunately, for today's purpose, only two stages are enough...
"Come on, let's go to the control room."
Chang Haonan looked back at the ready engine and said to Liang Shaoxiu next to him.
According to regulations, when the engine is undergoing any form of test run, except for necessary personnel under special circumstances, others must be protected.
When the two arrived at the control room on the third floor, several operators were already ready.
Zhang Zhenhua stepped forward quickly, then stood at attention:
"Mr. Chang, please give me the order!"
Although the occasion was quite serious, Chang Haonan almost couldn't stand up because of this somewhat subjective sentence structure.
Fortunately, I still forced myself to hold it back.
"Every number is in place!"
After regaining his composure, he took the microphone and reported the first test condition in a solemn tone:
"The first stage of takeoff: altitude 0km, Mach number 0.23, angle of attack 8°, far-field incoming flow turbulence intensity ratio and turbulence viscosity ratio 1%..."
As instructions were input into the control computer one after another, the pylon hoisting the aviation engine assembly quickly adjusted its attitude from completely horizontal to slightly upward.
The first stage simulates the stage where the aircraft has accelerated to take-off speed on the runway, but in order to prevent the tail from touching the ground, it can still only climb at a small elevation angle.
This process lasts very briefly during takeoff, but because the aircraft has speed but no altitude at this time, it is a very fatal accident-prone area.
"First test, ready to start!"
Immediately after Chang Haonan's voice fell, the test engineer slowly pushed the simulated throttle valve at hand to the end.
From the perspective of the control room, it can be seen that the blades inside the nacelle slowly begin to rotate, and the white spiral on the cone in the middle of the fan is also drawn into a pattern similar to an eagle eye——
According to many accounts, this design can reduce the probability of bird collision, or remind ground personnel that "the engine is working."
But in fact, these are the functions of the piston engine era.
For turbofan engines, it purely belongs to the corporate culture of airlines or aviation manufacturers.
Therefore, Chang Haonan specially found someone to design such a style that was very different from others, as a product feature of the Aviation Power Group.
The huge fan with a diameter of two meters may not feel like anything when you are at the airport, but when you actually put it in the workshop, you can still see it up close. After it is started, it still has some momentum.
While the sensors were collecting data, Liang Shaoxiu, who had been silent just now, stepped forward:
"Mr. Chang, if it is four turbofan 20s, it should be able to drive a large transport aircraft like the IL-76, right?"
Chang Haonan didn't answer, just tilted his head and glanced at the other party.
As an aircraft designer and a professional large-scale aircraft designer, this question is obviously asking knowingly.
So the focus must be on the back.
Sure enough, when Chang Haonan didn't answer anything, Liang Shaoxiu paused for a moment and continued:
"When the Yun-9 business is finished, can you please suggest to your superiors that it is time to start the development plan of a domestic strategic transport aircraft..."
Well, it turns out I was just waiting here.
But this is not difficult to understand.
The Y-9 prototype temporarily equipped with PS90A has entered the final stage of final assembly and is expected to complete its first flight before the Spring Festival of 2005.
Based on the experience of the past few years, this relatively stable model can be designed and finalized in about two years.
As for production and finalization...
That's not entirely the burden on Liang Shaoxiu's shoulders.
"I guess...the Air Force should already be demonstrating."
Chang Haonan did not agree directly, but still gave a quite optimistic response.
Even in the previous life, China's domestically produced large transport aircraft was officially launched in 2007.
In this timeline, although the larger number of IL-76MFs have provided China with quite sufficient strategic airlift power, after all, the objective conditions are quite sufficient, so there is no reason to be slower than in the previous life.
The only problem is that because the demonstration speed is too fast, Liang Shaoxiu cannot keep up with his own time, causing the project to fall into the hands of others.
In fact, considering that the aviation industry has accumulated considerable experience in products of the 100-ton level, and that the WS-20 should be fully mature by then, the 200-ton model may not even require his concern...
From this point of view, China's aviation industry is gradually getting on the right track and getting better.
Chang Haonan suddenly felt a little emotional when he thought of this.
It has been nearly 9 years since he was reborn.
And China's aviation industry has also developed from not being able to make second-generation and a half fighters to being able to mass-produce third-generation fighters, as well as trunk and large regional passenger aircraft at a rate of about 30 per year.
At the same time, it is also developing multiple new models at the same time.
It is no exaggeration to say that it has basically reached the research and development capabilities of the previous life around 2014.
Then the next step...
If nothing unexpected happens, the demonstration of the fourth-generation fighter will begin soon.
But this process should not require Chang Haonan to interfere too much.
And as long as limited improvements are made on the basis of the WS-10, it can be upgraded to a standard fourth-generation turbofan engine.
At that time, considering that China's materials and process level could not support such high performance, a relatively conservative solution was chosen.
Now that so many years have passed, it should not be difficult to provide a world-class engine for the new generation of fighter jets.
At least it is not enough to be the core work of the next stage.
"Is it hypersonic or variable cycle?"
Chang Haonan suddenly felt a little entangled-
Of course, he could support the advancement of both projects.
But the resources that China can currently provide do not support...
Fortunately, the happy troubles did not last too long.
The engine quickly entered a stable working state, and data points appeared on the computer screen in the control room one by one.
"Report to President Chang!"
The voice of an engineer interrupted Chang Haonan's thoughts:
"The fan and high-pressure compressor are working stably, and no obvious temperature and dynamic abnormalities are found. The total pressure at the inlet of the outer duct is 145.3Kpa, the total pressure at the inlet of the inner duct is 124.7Kpa, and the total pressure ratio is 41.7. It is little affected by the intercooling equipment on the back of the stator blade..."
"Due to the influence of the incoming flow attack angle, airflow stagnation points appear outside the upper and lower lips of the nacelle. The airflow speed inside the lower lip is Mach number 0.861 at the fastest point. The total pressure recovery coefficient of the nacelle itself is 99.62%, and the distortion index is 1.13%..."
"..."
Without the combustion chamber and turbine installed, most of the performance cannot be accurately measured.
But even so, the current test results undoubtedly show that Chang Haonan's choice of integrating the intercooler and the compressor design can be said to be a great success.
In addition, the engine nacelle with the turbofan 20 also shows excellent adaptability.
Although the engine of this model is not yet highly completed, at least there is no need to worry about the fundamental risk of technical errors.
And this is enough for Chang Haonan at present.
"Prepare to adjust the test conditions!"
He ordered calmly:
"Takeoff stage 2: altitude 0.03km, Mach number 0.28, angle of attack 15°..."
The second stage is the normal climbing process.
Compared with the first stage, the flight conditions are more demanding, but the risk is not that high.
And in essence, the characteristics of these two stages are quite similar, so since the data of the first stage is normal, there should be no major problems in the second stage...
Sure enough, after the angle of attack and speed are increased at the same time, the only obvious change is that the peak Mach number of the lower wall has increased by 0.161, thus exceeding the speed of sound. Although the rest of the total pressure recovery coefficient, boost ratio, and distortion index have deteriorated, they will hardly affect the normal working state of the engine.
The fact that the total pressure data at the entrance of the inner and outer ducts has hardly changed is proof of this...
"Lao Zhang."
Chang Haonan glanced at his watch, then waved to Zhang Zhenhua who was not far away:
"Ask the publicity department to produce a report on today's test. Don't mention specific performance indicators or models. Just emphasize our requirements for the next generation of high bypass ratio turbofan engines in terms of exhaust emissions and fuel consumption rate..."
"By the way, in conjunction with the recently launched fourth round of IPCC environmental assessments, we must stand firm on the moral high ground so that we can send enough signals and pressure to the outside world..."