At present, AL-3 1FN is better, and the acceleration, air start-up envelope and ground start-up time are better.
At present, the ground start-up time of turbofan-10 is about 90 seconds, and that of AL-3 1FN is only one minute.
After we stop in the air, the lower speed limit of starting the windmill is about 600 km/h, and AL-3 1FN only needs 450 km/h;
In terms of acceleration performance, AL-3 1FN only needs 5 seconds to speed up, and we need more than 5 seconds.
Among these shortcomings, the most important thing is to start the envelope in the air, because this is a single-engine aircraft. After stopping, you need to reduce the height to improve the speed. If the parking height is low, it may not be high enough to accelerate to 600 km/h, so you need to parachute and abandon the plane.
After reading this interview, I felt so happy a while ago. I always thought Taihang came out too late. When designing, I can "stand on the shoulders of giants". I have the physical reference of AL3 1 and an American engine. I use the American military standard, so all the performances should be higher than AL3 1. I didn't expect it to be Al 3 18 in the eyes of test pilots. Although Taihang has a slight advantage in thrust-to-weight ratio and maximum afterburner thrust, it can be seen that Taihang is still inferior to Russian goods in several aspects that are usually inconspicuous but quite important. The ground start-up time affects the speed of the fighter in an emergency, and the acceleration affects the maneuverability of the fighter. The lower limit speed of the windmill is too high, which means that when the fighter stops in the air, there is little time and opportunity to start the engine again. If the altitude is a little lower, the food will stop completely. The gap between Taihang 600 km/h and al 3 1FN 450km/h is obvious. As for the reliability, I'm afraid Taihang can't compare with AL3 1 which was put into use more than 20 years ago. It is believed that J- 1 1 is prepared to mix Taihang and AL3 1 for this purpose (the problem of different engine weights can only be solved by increasing the counterweight), and even if one engine has problems, it can fly back from the other.
The author's point of view seems to be: 1, the engine control system of Taihang is basically transplanted from AL3 1, and Russian experts participate in the design work, so it is not fully adapted to the situation of Taihang. 2. The power of the gas turbine starter is not large enough. The above two points have been prepared or are being improved, and the defects of too high starting speed and too long starting time of Taihang windmill are not irreparable.
Let's compare the interviews with the most famous journalists in the Military Science and Technology Supplement:
The reporter asked:
At present, J 10 uses Russian AL-3 1FN engine, and it is possible to replace it with our domestic Taihang engine in the future. So, are these two engines better?
Li Cunbao, a test pilot, said: At present, AL-3 1FN is better, and its acceleration, air start envelope and ground start time are better. At present, the ground start-up time of turbofan-10 is about 90 seconds, and that of AL-3 1FN is only one minute.
After we stop in the air, the lower speed limit of starting the windmill is about 600 km/h, and AL-3 1FN only needs 450 km/h. In terms of acceleration performance, AL-3 1FN only needs 5 seconds to speed up, and we have to exceed 5 seconds.
Among these shortcomings, the most important thing is to start the envelope in the air, because this is a single-engine aircraft. After stopping, you need to reduce the height to improve the speed. If the parking height is low, it may not be high enough to accelerate to 600 km/h, so you need to parachute and abandon the plane.
The following is the original of netizen aliasmaya:
What a family says is mostly speculation. Please criticize and correct me! I also very much hope that you can comment on the acceleration performance, windmill characteristics, starter and adjustment scheme of turbofan 10. Regarding the starting problem of turbofan 10 in air windmill, if you are interested, it is suggested to consult the paper published in a certain issue of Aeroengine in 2004. Zhang has made a special discussion on this. Based on the improved fuel supply law, the engine ground starting test and air windmill starting test were carried out, and some data were obtained. The left boundary of air start is: H=4km, Ma=0.52, VB = 500 km/h. ......
The concept of "windmill" means that the engine stops running for various reasons, but the engine continues to rotate under the joint action of aerodynamic force, rotor inertia and resistance moment, and it is stable at a certain speed in a short time. It is very important to start the engine in the air windmill.
ал-31Ф has good pungent property, large compressor surge margin, strong distortion resistance (temperature and pressure), and good combustion chamber ignition characteristics (remember that there are 28 nozzles and 20 in Taihang), which is very beneficial to improve the engine acceleration performance (but it needs to be exchanged for weight), and the acceleration line can be larger. Russian hybrid control system is considered as a model of hydraulic machinery-analog electronic control system design. I think the introduction of piecewise compound control law in the manual is really nerve-racking! I admire their designers' ingenious realization of engineering application.
I think that transplanting ал-31Ф hybrid control system to turbofan 10 will cause many problems, and it is a process of continuous exposure and improvement in a certain period of time. At present, the acceleration, starting time and starting boundary of turbofan 10 are narrow, which seems to be related to the incompatibility and mismatch of the prototype adjustment scheme. The adaptive improvement needs to be developed on the basis of thoroughly understanding the design principle of the prototype and absorbing its essence (this tests the ability of 1 13 and 6 14, and it is estimated that the cost of inviting foreign aid is high.
In addition, the ignition characteristics of the main combustion chamber need to be improved (the ignition boundary between lean and rich oil is relatively narrow), which is a congenital problem and inherited from F 10 1.
I have seen many papers talking about this aspect, and put forward improvement measures, such as improvement and optimization of acceleration control, analysis of starting characteristics of air windmill, improvement of ignition characteristics of combustion chamber and so on.
As for the start-up time of turbofan 10 is longer than ал-31Ф, I guess there are several possible factors, such as the power of gas turbine starter is not strong enough, the ignition speed of turbofan 10 is relatively high, and the disengagement speed of starter may be higher than ал-3/kloc-0. 20%, ал-31Ф is about 15%. Because of the small air flow and low pressure in the main combustion chamber, the pneumatic atomization performance is poor during the start-up process and at low speed, and the boundary of lean oil flameout is narrow. I remember this is a "special problem in two-phase combustion" in the textbook, so I chose a higher speed point. The key is that the combustion chamber has an appropriate oil-gas ratio to ensure reliable ignition and stable operation, which also depends on the design of oil supply scheme.
The turbofan 10 adopts the starter developed by 608 (I don't know if it means гтдэ-17, as shown in the figure), and the power-increasing type is still under development. I guess the gap in the start-up of the aerial windmill is still due to the adaptability between the regulation scheme of ал-31Ф and the characteristics of the turbofan 10 which does not adopt FADEC at present. In addition, it is necessary to improve the ignition characteristics of the main combustion chamber.
It is one of the urgent measures to replace the domestic 6 14 electric modulation with turbofan 10 and give full play to the performance potential of the engine.
The flame tube head of turbofan 10 is designed to be lean (the pursuit of high temperature rise can obtain high pre-turbine temperature, so it is necessary to increase the oil supply, but at the same time, to prevent smoking, it can only increase the air intake, resulting in a decrease in the oil-gas ratio, which is prone to lean flameout in low working conditions), and the ignition characteristics and stability are relatively strict.
Some measures to improve the starting performance of windmill can be added with the reliability of oxygen supplement system and ignition device. Maybe there is a ал-31Ф start-up oxygen supply system?
I guess ал-31Ф has good acceleration, which may be largely due to the high surge margin. Shortening the acceleration time requires more turbine surplus power, that is, rapidly increasing the pre-turbine temperature T4. During the acceleration process, the oil supply needs to be increased rapidly (within the limit, the bigger the better), but the increased T4 will have an adverse effect on the stable operation of the high-pressure compressor (it tends to the surge boundary, because the inertia of the high-pressure rotor is large, and the increase of speed cannot keep up with the increase of T4). If the surge margin of the compressor is large, the acceleration line can deviate from the steady-state working line to a greater extent, that is to say, a shorter acceleration path can be taken. The high pressure ratio and stage load level of turbofan 10 high-pressure compressor may be one of the factors leading to poor engine acceleration.
The previously translated ал-31Ф acceleration and deceleration performance and starting parameters are quoted from уурбореактивн.
10, acceleration time:
A) accelerate from the local train to the maximum state (пнд value is lower than пндогр.2%)
-H=0、Ma=0 3-5s
-H & lt； 8 km ≤5 seconds
-H & gt； 8 km ≤8 seconds
B) accelerate from idle speed to full afterburner, H=0, Ma=0 (until afterburner ignition signal is displayed) ≤7s.
C) From the maximum state to 0.95 рпФ ≤ 3s.
1 1, and the time from the maximum state to the idle speed (H=0, Ma = 0) is 4-6s.
12. Start time (to the maximum output state) Press and hold the start button for 60-80s.
The starting time of гтдз starter on the ground bench (to idle state) is ≤50s.
Total startup times
Number of engine starts (using power supply with its own battery, no need to charge) 5.