Start with the aviation industry

Chapter 202 Turbine Disc Assembly

Entering an aircraft final assembly shop is of course different.

Lin Feng was the first to put on clean white cotton slippers, and the others did the same, changing shoes one after another.

Although it is not a dust-free workshop, the cleanliness required by the aircraft assembly workshop is relatively high, mainly to prevent foreign matter from entering the aero-engine during the assembly process.

After changing into clean cotton slippers and walking into the huge aircraft assembly workshop, the first impression is that the ground is very clean. The green epoxy resin floor is so clean that people can almost be seen on it.

There are about dozens of workers at the assembly site, who are doing the pre-assembly of the first verification machine, that is, the assembly of the components of this verification machine.

Such as the assembly of turbine components.

The LH1500 turboshaft engine has a total of first and second turbines, plus a free turbine.

On the assembly station, several workers are assembling the first and second turbines. Each turbine blade has been weighed, and the turbine disc has been dynamically balanced, and the direction of the center of gravity has been marked.

One of the workers took a pneumatic vibrating pen and carefully marked a small "1" next to one of the mortises of the first-stage turbine.

This is the No. 1 tongue and groove.

The determination of the No. 1 tenon groove is completely determined by the direction of the center of gravity of the turbine disk. After marking the No. 1 tenon groove, a turbine blade with the lightest weight is selected to be installed in this tenon groove.

He held a copper rod in one hand and a hammer in the other, and lightly tapped one end of the copper rod.

During this kind of beating, the locking piece of the turbine blade began to bend, and finally fit tightly on the end surface of the turbine disk.

After the first turbine blade was assembled, he gently moved the turbine blade a few times with his hands to feel the swing of the blade.

After the turbine blade is installed and the locking plate is locked, the turbine blade does not remain motionless in the tenon and groove, but requires a certain amount of activity, that is, the amount of swing.

Experienced assembly workers can basically determine whether the swing of the blade meets the process requirements by feeling.

It is definitely not possible to stay still. The amount of swing is too small or too large. It has a range, and the amount of swing must be within this technological range.

After the first blade is installed, the second turbine blade is installed in the symmetrical tenon and groove. The blade selected this time is the opposite, no longer the lightest blade, but the heaviest turbine blade.

Due to manufacturing errors, the weight of each turbine blade is not exactly the same, but there will be a weight difference of about one or two grams at most. If the weight of the blades is inconsistent, it must be considered that the mass distribution should be as uniform as possible during assembly. .

If the mass distribution is uneven, the vibration will be very severe at a high speed of up to tens of thousands of revolutions, and the machine may be destroyed if it is not done well.

Therefore, the vibration must be controlled within a relatively small range, which requires uniform weight distribution, and there are strict technological requirements in the assembly process of the turbine disk and turbine blades.

Install the second leaf, then the third, and the fourth.
There are [-] to [-] turbine blades in the first-stage turbine disk. The transfer worker skillfully assembled the first-stage turbine disk. When Lin Feng walked to this station, the first-stage turbine disk was basically assembled.

"Mr. Lin, hello!"

"Hello, leaders."

Whether it was the assembly workers or the technicians in charge of technical guidance here, they all took the initiative to say hello to Lin Feng and the others.

Without any airs, Lin Feng said heartily, "We haven't affected your assembly work, have we?"

"No no."

Lin Feng saw that the first-stage turbine disk was basically transferred, and he said with satisfaction, "Your speed should be the fastest, but you must remember that quality comes first, especially the parts of the turbine part, which are the most critical parts of the entire engine. part."

"The first-stage turbine disk has been assembled, how about the swing of the blades, let me have a look."

Lin Feng wanted to take a look at the assembly quality. After the turbine disk was assembled, the swing amount of each blade must be measured, and the swing amount of each blade must be within the range required by the process.

"Do as Mr. Lin said, and measure the swing of each blade."

Ye Jianhui, director of the assembly workshop, ordered.

He is a talent poached by the Human Resources Department. He has a bachelor's degree and has worked in the aviation industry for 20 years. He understands the assembly of aero-engines and has rich management experience.

The test of the amount of swing of the turbine blades will start immediately.

The assembler put the assembled turbine disk on the test fixture, installed the dial indicator, and then began to test piece by piece.

There is also a worker next to each other to cooperate with each other, and the swing amount of each turbine blade is recorded on a dedicated form.

This is one of the assembly records. Each engine has various assembly records during the assembly process. After the engine is tested, all assembly records, inspection reports, process cards, etc. are bound into a thick book.

This is the history book of the engine.

This is also the identity record of each engine. After the engine leaves the factory, the resume will be kept. It may be kept for more than ten years, or even twenty years, until the engine reaches the end of its life and is completely scrapped.

"Blade No. 1, the swing amount is 36 wires."

"Blade No. 2, the swing amount is 34 wires."

"Blade No. 3, the swing amount is 42 wires."

"."

One of the workers reported a number every time he measured the swing of a blade, and the other worker recorded each number on the form.

More than 10 blades were tested in less than 30 minutes. The process requires that the swing of each blade is between 50 and [-] wires.

The swing amount of the No. 5 blade is exactly 30 wires, and the swing amount of the No. 32 blade is 49 wires.

Lin Feng said, "See, blades 5 and 32 are only barely qualified. This is our first verification machine, and it must be made into a high-quality product. These two blades need to be reassembled or replaced. The right blade."

Ye Jianhui said, "President Lin, don't worry, we will definitely follow your request and make this engine a high-quality product."

Quality first is not a slogan.

It runs through the entire process of aero-engines, from manufacturing to aircraft assembly to test run, and strict quality control is necessary in every process.

The assembler immediately reassembled the two blades and then tested the blade swing.

The swing of the No. 5 blade was originally 30 wires, which was a bit too small. After reassembly, the swing amount reached 35 wires, which is much better than before and meets the requirements.

The swing amount of the No. 32 blade was originally 49 wires, but it was 43 wires after reassembly, which is much better.

After all the blades are assembled, the swing amount of each blade meets the requirements, but it does not mean that the assembly of the turbine disk is completed, and there is still a very important process.

That is:
Balance!
The purpose of dynamic balancing is to check whether the mass distribution of the turbine disk is uniform and whether it meets the process requirements.

This requires a dynamic balancing machine.

Lin Feng waved his hand and said, "Let's take a look at the dynamic balance together."

Everyone went to the dynamic balance area together, where there are two dynamic balancing machines, one large and one small, each with the eye-catching logo of Leihuo Technology Industry Group.

They are all independently developed and manufactured by Leihuo Technology Industrial Group, with advanced design and excellent performance.

The Phoenix factory has already ordered two sets, and one of them will be delivered to them in about a month.

The first-stage turbine disk of the LH1500 turboshaft engine is not too big. Even if it is filled with blades, the maximum outer diameter is not 300, and the weight is not too heavy. It can be picked up with one hand. The worker in charge of dynamic balance installs it On top of that smaller balancing machine.

First of all, start to find the alignment, using the dial indicator. While slowly turning the turbine disc, while watching the change of the pointer on the dial indicator, the worker gently taps it with a copper rod.

After a while, the alignment was completed, and the pointer of the dial gauge jumped within [-]/[-], which met the technical requirements.

Then, he took a marker and made a mark on the turbine disk, which represented the zero position of the turbine disk.

Balancing begins.

The safety door of this dynamic balancing machine was closed, and the machine started. The turbine disc rotated rapidly, and the speed climbed all the way, until the speed reached 5000 rpm before it stabilized and did not continue to climb.

The dynamic balance display also shows the dynamic balance amount, as well as the position and direction of the mass center of gravity.

Dynamic balance 7.2g/mm
The design requirement does not exceed 5g/mm
The unqualified dynamic balance means that the turbine disc assembled with turbine blades does not meet the requirements, and the mass distribution is uneven.

How to do it?

Lin Feng personally commanded, "The dynamic balance is a bit too large, take down the turbine disc and remove the material."

The worker in charge of dynamic balancing opened the cover of the dynamic balancing machine and made a mark in the direction of the center of gravity with a red pen.

Then take down the turbine disc, hold the pneumatic grinding gun in your hand, and start grinding at the position opposite to the position marked just now, which is 180 degrees.

The design of the turbine disk takes this situation into consideration. What if the dynamic balance fails? There is a circle on the turbine disk where metal materials can be removed.

The worker carefully polished and removed the metal material in that area. Under the grinding of the alloy milling head, the metal material was gradually removed, and more and more metal materials were removed. At least two or three grams of metal material was removed in a while.

He stopped.

Obviously, it is going to be temporarily removed here, and then the turbine disk will be dynamically balanced. If it is unqualified, then continue to remove the metal material on the turbine disk according to the dynamic balance situation.

Generally, it needs to be repeated several times until it is finally qualified. If all the materials that can be removed have been removed, but the dynamic balance is still unqualified, then the last solution can only be adopted, that is, to install a counterweight on the turbine disk.

It is generally not done unless it is absolutely necessary.

Lin Feng said, "It's not enough, we must continue to polish and remove materials."

The worker hesitated a little, looked at Lin Feng, and probably thought in his heart, Mr. Lin, how do you know it's not enough, and you have to continue to polish it.

Lin Feng saw his hesitation, and said loudly, "Do as I say, I will stop, you stop again."

After finishing speaking, Lin Feng also picked up a marker pen and drew a small area where the metal material needs to be removed, "Remove the metal material at this position."

The worker held a pneumatic grinding gun, and according to Lin Feng's instructions, continued to grind at the position marked just now, and continued to remove the metal material on the turbine disk.

"Okay, that's it."

Seeing that the polishing was almost done, Lin Feng called to stop, and signaled to do a dynamic balance and then take a look.

This turbine disk is again dynamically balanced.

3.1g/mm
This is a very good data.

It is impossible for the dynamic balance to be zero. After reaching a relatively small value, it cannot be smaller. Because of manufacturing errors, assembly errors, etc., when a series of errors exist, it is very good to reach about 3g/mm.

perfect!

Lin Feng said with satisfaction, "This dynamic balance is enough."

The assembly of the first-stage turbine disk was completed, Lin Feng did not continue to watch the assembly of the second-stage turbine disk here, but went to other stations to check the assembly of other parts.

Lin Feng spent at least one or two hours in the aircraft assembly workshop to get a clear picture of the assembly status of each component before leaving.

In a bright and spacious office.

Lin Feng and Wang Yalong chatted about the assembly of the first verification machine while drinking tea.

Wang Yalong said, "Boss, so far, we have completed the assembly of the first and second turbine disks, the free turbine disk, the combustion chamber and other components, and the parts required for the final assembly are further complete. These are the missing parts. list."

After speaking, he gave Lin Feng the list of missing parts.

After taking this list, Lin Feng looked at it, and found that there were still 27 parts with drawing numbers missing, of which 25 parts with drawing numbers were purchased parts, and only two parts were manufactured and processed.

Lin Feng said, "When will all these parts arrive at the latest."

Wang Yalong said, "I have already implemented it. Within a week, they will all be here."

Assembly does not start until all the parts are complete. Most of the parts are in place, and the assembly of some parts can start.

When all the parts are in order, the final assembly of this verification machine can start.

Lin Feng said, "A week later, the final assembly of our verification machine will begin."

Wang Yalong nodded and said in his heart, "Boss, I'm really looking forward to this verification machine. I wonder if it can pass the verification at once."

The verification machine is used to verify the whole machine. Through the test run, see whether the performance meets the design requirements.

If all the data meet the design requirements, it means that the design verification is passed, but the design verification is rarely passed at one time, or almost never, and it usually needs to be repeated many times.

After the test run is unqualified, analyze and summarize the reasons, design improvement and perfection, and then test run, if the unqualified design is improved and completed, it is possible to go through many times, even two or three years.

"Aviation News" is a professional newspaper with the largest circulation and the greatest influence in the domestic aviation industry.

Basically every aviation industry enterprise, related colleges, design institutes, etc. will subscribe to this newspaper, publish it every day, and distribute it every day.

An aero-engine factory.

In the large office of the Engineering Technology Department, [-] to [-] engineers and technicians were immersed in their work. At nine o'clock in the morning, the clerk in charge of distributing newspapers and magazines took a stack of newspapers and put them on the big desk in the office.

A young engineering technician asked, "Sister Wen, this is today's new newspaper."

"Yes, I just brought it back, and it's full of today's new newspapers."

Hearing this, the young technician walked over excitedly and looked through at least five different newspapers, including today's "Aviation Daily".

He first picked up the "Aviation Daily" and sat by the big table to read it. Soon, several technicians came over, each took a newspaper, and sat by the big table to read it.

Taking time out to read newspapers during working hours seems to have become a tradition, a way for everyone to relax, and even a means of understanding outside information.

"Hey, no way!"

"The world-class turboshaft engine has entered the final assembly stage of the verification machine!"

The front page headline of today's "Aviation Daily" is full of pictures and texts, and a large-scale report on the LH1500 turboshaft engine.

This is a world-class turboshaft engine. The overall performance and technical content of the design are still higher than the T700-GE-700 turboshaft engine in the United States.

This is impossible!
After a few glances at the report, it's no wonder the young technician exclaimed, it's unbelievable.

"Xiao Liu, what's wrong!"

Xiao Liu, a young technician, pointed at the newspaper and said loudly, "Take a look, Leihuo Technology Industrial Group has successfully designed and developed a world-class turboshaft engine, and the first verification machine has entered the final assembly stage!"

"Let me see!"

Soon, several technicians came over and looked at the report on the LH1500 turboshaft engine in the "Aviation Daily" with great interest.

In addition to a large number of written reports, there are also color pictures of this turboshaft engine and some performance parameters.

Everyone is engaged in engines, and none of them are laymen. After reading this report, they let out a sound of exclamation.

"Can not believe it!"

"This is definitely a world-class level."

"It's so exciting, we actually developed such an advanced turboshaft engine in China!"

"."

The originally quiet big office suddenly became lively, and this "Aviation Daily" became a favorite in an instant, and everyone rushed to read it.

Some people are excited, some people are deeply proud!
The news was also spread throughout the domestic aviation industry system, and more and more people knew about Leihuo Technology Industry Group and this world-class turboshaft engine.

However, some people don't believe it.

For example, in a large office of an aircraft manufacturing factory, some people are talking about this turboshaft engine.

"I absolutely don't believe it. With the level of our domestic aviation industry, how is it possible!"

"If Leihuo Technology and Industry Group can really develop this turboshaft engine, I will eat it."

"Not necessarily, after all, it is a report on the "Aviation News", and it is still on the front page."

"."

A helicopter design institute.

The institute is holding a meeting. Except for the leader, the others are all experts and technical backbones of future medium-sized special armed helicopters.

On the conference table, there are several copies of today's "Aviation News". The front page of this newspaper is a large report on the turboshaft engine of Leihuo Technology Industry Group.

(End of this chapter)