Chapter 1169 Next step, hypersonic or variable circulation?
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...
"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 the order!"
Although the occasion was quite serious, this somewhat subjective sentence structure still made Chang Haonan almost stop.
Fortunately, I still forced myself to hold it back.
"Every number is in place!"
After calming down, 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, came 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 aircraft designer, this question is obviously asking knowingly.
So the focus must be on the back.
Sure enough, seeing Chang Haonan not answering, 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 hundreds of tons of products, and the turbofan 20 should have been completely mature by that time, it is even possible that the 200-ton model does not require him at all. Worry...
From this point of view, China's aviation industry is gradually getting on the right track and is really getting better.
Chang Haonan suddenly felt emotional when he thought of this.
It has been nearly nine years since he was reborn.
China Aviation Industry has also developed step by step from manufacturing second- and a half-generation fighter jets to being able to mass-produce third-generation fighter jets at a rate of about 30 per year, as well as mainline and large regional passenger aircraft.
At the same time, multiple new models are being developed simultaneously.
It is no exaggeration to say that it has basically reached the research and development capabilities of its previous life around 2014.
So the next step...
If nothing else, the debate on fourth-generation fighter jets will soon begin.
But this process should not require too much interference from Chang Haonan.
Moreover, as long as limited improvements are made on the basis of Turbofan 10, it can be upgraded to a standard fourth-generation turbofan engine.
At that time, it was considered that China's materials and process levels did not support such high performance, so a relatively conservative plan was chosen.
Now that so many years have passed, it should not be difficult to simultaneously provide a new generation of fighter jets with an engine that benchmarks against world-class standards.
At least not enough to serve as the core work of the next phase.
"Is it hypersonic speed or variable circulation?"
Chang Haonan suddenly felt a little confused——
He himself could certainly support both projects moving forward together.
However, the resources that China can currently provide do not support...
Fortunately, the troubles of happiness did not last long.
The engine quickly entered a stable working state, and each data point appeared on the computer screen in the control room.
"Report to Mr. Chang!"
An engineer's voice interrupted Chang Haonan's thoughts:
"The fan and high-pressure compressor are working stably, and no obvious temperature or 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 boost ratio is 41.7, which is affected by the intercooling equipment on the back of the stator blades. Very small..."
"Due to the influence of the incoming flow angle of attack, 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%, distortion index 1.13%..."
"..."
Without the combustion chamber and turbine installed, much 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 compressor design was a great success.
Moreover, the engine pod equipped with the turbofan 20 also shows excellent adaptability.
Although the engine itself of this model is not very complete, at least there is no need to worry about the fundamental risk of technical route errors.
And this is enough for the current Chang Haonan.
"Get ready to adjust the test conditions!"
He ordered in a calm tone:
"Second stage of takeoff: 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 risks are not that high.
And in essence, the characteristics of these two stages are quite close, so since the data in the first stage is normal, there should be no big problems in the second stage...
Sure enough, after the angle of attack and speed were increased at the same time, the only obvious change was that the peak Mach number of the lower wall increased by 0.161, thus exceeding the speed of sound. Although the rest of the total pressure recovery coefficient, boost ratio, and distortion index all deteriorated, But it will hardly affect the normal working condition of the engine.
The fact that the total pressure data at the entrance of the inner and outer culverts has hardly changed is proof...
"Old Zhang."
Chang Haonan glanced at his watch, and then waved to Zhang Zhenhua who was not far away:
"You ask the publicity department to publish a report on today's test. Don't mention specific performance indicators or models. Just focus on our requirements for the next generation of high-bypass-ratio turbofan engines in terms of exhaust emissions and fuel consumption. …”
"By the way, combined with the IPCC fourth round of environmental assessment that has just started recently, we must stand on the moral high ground, so as to release enough signals and pressure to the outside world..."
(End of chapter)