The military-industrial scientific research system of the academic master.

Chapter 1424 Unique Skills
The temperature in June is almost the same every day.

When Chang Haonan got off the plane, although summer had already arrived in the Gobi Desert, the overall temperature was still relatively suitable.

However, less than a week later, when the launch test was scheduled to take place, the gravel-covered ground was even able to produce distorted heat waves visible to the naked eye under the scorching sun.

Chang Haonan took off his safety helmet and wiped the sweat from his forehead. He heard the buzzing sound of Han Chenfeng and Wang Zhenguo communicating with each other.

He looked through the glass of the control room at the nine-meter-long electromagnetic track.

Or to be more precise, it is looking at the cooling pipes wrapped around the track, winding like a dormant mechanical python.

Compared to gunpowder power, which converts chemical energy into internal energy and then expands to do work, the heat generated by the motor is indeed much less, but the current extreme temperature conditions have indeed approached the limit considered when designing this system.

"Report, the hydrogen-oxygen mixture ratio has been calibrated. It is estimated that the detonation chamber pressure can be controlled at 12 MPa, which is far below the safety limit."

Wang Zhenguo's report came from the intercom, with the tension of the approaching experiment:
"All safety membranes and safety valves have been inspected and all meet the design requirements..."

"..."

"If we want to conduct a continuous firing test, then at a rate of 12-15 rounds per minute for one duty cycle, will the pressure in the disc-type power generation channel not be able to be released in time?"

Ma Mingwei, still wearing his navy work clothes, looked down at the structural diagram of the magnetohydrodynamic power generation module and asked.

Originally, his visit was expected to last only two days.

But when he heard that the gun would soon be put to work testing, he decided to stay a few more days to witness with his own eyes the results of the application of magnetohydrodynamic power generation technology in the field of electromagnetic launch.

As a top-level researcher, it is of course impossible for him to just sit and wait.

I also took this opportunity to learn a lot of relevant technical knowledge.

After a few days, although I cannot be called an expert in magnetic fluids, the questions I raised have become more targeted.

"Actually, yes... One of the main disadvantages of a disk-type generator compared to a pipe-type generator is that the state recovery process takes a long time."

Chang Haonan put down the checklist in his hand and replied:
"However, there is a pressure relief nozzle between the detonation tube and the generator. The disc channel itself does not mainly bear pressure, so as long as the detonation tube itself can hold up, there will be no risk of overpressure in the subsequent part... Moreover, we have also set up a safety diaphragm for emergency pressure relief."

"In contrast, when multiple detonation tubes work in turns in a short period of time, the greater hidden danger is that the subsequent distribution of ionized seeds may be disordered, resulting in the fire control system's adjustment accuracy of muzzle kinetic energy being affected as the number of firings increases... In theory, the problem can be solved by setting a redistribution module behind the power generation channel. Of course, this needs to be gradually verified during the test process. At this stage, the ionized seeds are replenished after each round of work to ensure that the concentration of the magnetic fluid is high rather than low."

As soon as he finished speaking, he heard Han Chenfeng beside him pick up the intercom and confirm with Wang Zhenguo who was working at a distant workstation:
"Please confirm the status of the coolant pump and valve, and prepare to start the liquid cooling system test!"

A few minutes later, with a dull humming sound, a warning light marked "Cooling Cycle" on the console turned from yellow to green, indicating that it had entered working condition.

The cooling water mixed with some alcohol is cooled by air-conditioning equipment and sent into orbit, and then slowly fills the cooling circuit wrapped around the surface of the gun barrel.

From Chang Haonan's direction, he could even vaguely see that water vapor began to condense on the outer wall of the pipe, and then gradually gathered into droplets, and then formed a trickle -

Although the Gobi environment is dry, it is not a real desert after all, and it is not so dry that there is no humidity at all.

"Speaking of cooling systems..."

Ma Mingwei raised the telescope in his hand, seemingly carefully observing the arrangement and design details of the condensation circuit:

"I thought you would just integrate the cooling channel and the launch rail together, but I didn't expect it to be like this..."

He hesitated for a moment, and finally found a suitable adjective:
"Such a classic external contact structure?"

Chang Haonan certainly knew that the real meaning the other party wanted to express was simple. After all, even he felt so at the beginning:

"If they are to be put into practical use, they must be combined together and designed with internal cooling channels to achieve convection cooling... But this monolithic structure cannot be modified once the design is completed, which does not meet our test requirements."

In fact, for the entire electromagnetic gun project, the cooling system is a relatively simple part. Chang Haonan just thought the other party was asking casually.

But Ma Mingwei suddenly became interested in this topic:

"Does this mean that there is room for further optimization of the cooling channel design?"

Chang Haonan shrugged:

"Of course……"

He originally wanted to take the other person outside to discuss the details, but considering that the test station was surrounded by busy staff, it was not very convenient, so he directly opened the design drawing of the liquid cooling system on the computer:
"In fact, even now, the cooling intensity corresponding to different parts of the track is different, but it is difficult to distinguish from a distance."

Sure enough, upon closer inspection, it is not difficult to discover that the cooling pipeline, which appears to be an integrated whole, actually consists of two unconnected parts, which are responsible for the head and tail ends and the middle of the launch track respectively.

Ma Mingwei was not clear about the labeling habits within the aviation system, but it was easy to understand that the temperature and flow rate of the coolant were different.

"We specifically studied the heat distribution of the electromagnetic track during continuous and rapid firing in combination with the motion characteristics of the armature, and the result is a two-dimensional electromagnetic-thermodynamic coupling model."

Chang Haonan pointed to the long launch rail on the screen and introduced:

"Qualitatively speaking, the Joule heat generated by the electromagnetic track itself is concentrated in the front half, that is, near the breech block, while the friction heat generated by the contact area between the track and the armature is concentrated in the middle and rear section, that is, near the muzzle. Overall, it presents a characteristic of being high in the middle and low at both ends."

"Another point worth mentioning is that due to the influence of the skin effect, the current will be concentrated on the edges around the contact surface of the rail pivot, resulting in higher temperatures on the contact surface boundary and lower temperatures in the central area. Therefore, even if you want to design an internal cooling channel, you can't just make the slide rail hollow and then fill it with coolant like the conventional solution..."

Originally, the communication between the two could only be considered as casual chatting during the test preparation period.

But at this point, the nature of the situation has changed a bit.

Although Ma Mingwei did not yet take out a notebook, he asked more and more detailed questions about the cooling system design, and it was obvious that he was really interested in it.

After all, the cost of electromagnetic catapult verification equipment is hundreds or thousands of times that of a simple electromagnetic gun, so it always helps to have some preparations before actually starting work.

But the deeper the discussion went, the more Ma Mingwei felt that this thing might not be something that could be explained in just a few words...

"What about the inside of the motor?"

He asked:

"Compared to being exposed to the outside, and the copper rails, the greater heat load should occur in the motor part... Why don't I see a dedicated cooling channel in the design drawing?"

Just at this moment, a window popped up on one of the console's screens.

It indicates that the cooling cycle is about to start and requires the operator to make a final confirmation of the tightness of the shielding sleeve.

“This is our unique skill.”

Chang Haonan said as he clicked the confirmation button, then turned on the "motor" part of the cooling control system:
"We borrowed some inspiration from the cooling circulation system of nuclear shielded pumps, separated the stator and rotor by an extremely thin shield sleeve, and replaced the traditional bearings used at the fulcrum with non-contact magnetic bearings, thus converting the dynamic seal into a static seal... In this way, the coolant can be directly filled into the motor without directly contacting the stator core and windings."

"Although as a price, the existence of the stator and rotor shield will increase the effective air gap of the motor and bring greater eddy current losses...but overall, the benefits brought by the improved cooling efficiency are greater."

This time, Ma Mingwei finally did not take the initiative to continue the topic, but just stared at the screen and pondered for a while.

"Academician Chang."

He raised his head seriously:
"I think after I leave Dingxin Base, I need to find an opportunity to go to Beijing to discuss with you about the thermal management of the electromagnetic track system..."

(End of this chapter)