Time passes minute by minute.

Half an hour later.

"The command center, the command center, the helium drainage is completed, and the temperature measurement of the pump housing is still 15k higher than the standard temperature..."

The news sent back from the front made the atmosphere in the hall of the command and control center suddenly become solemn.

"Old Wu, is there any other way?"

Launch Commander-in-Chief Wang Yudao.

Wu Chunmin shook his head and smiled bitterly: "Although the natural cycle pre-cooling mode is simple, this is the only measure that can be taken at present. Even if other methods are useful, they will take time. The launch window is too close, and we don't have enough time to improve a new pre-cooling plan."

"If you are overtemperature 15k, how big is the launch risk?"

"It's hard to say, but it's very likely to have an impact on engine ignition."

Wang Yu turned his gaze to Liu Xuesong again: "Old Liu, what do you think?"

Liu Xuesong said: "The space launch does not allow for any luck. We cannot let a problematic rocket hit the sky!"

"In this case, this launch may have to be cancelled."

"Even if it is cancelled, it will probably not be a short time to find out the failure of the pre-cooling system. This will not only affect the subsequent project of the 921 Rocket, but also have a great impact even if the progress of the aerospace plane project is progressing."

For a moment, people in the hall were talking.

Liu Xuesong looked at Pang Xuelin who was standing aside and silently, feeling helpless.

Originally, he wanted to invite Pang Xuelin to come and let him see the 921 Rocket, a product that represents the highest level in China's aerospace industry. Unexpectedly, such a big mistake was made before launch, which made people look down upon it for nothing.

Wang Yu said: "If it really doesn't work, you can only order the launch procedure to delay this mission."

"etc!"

At this moment, Pang Xuelin's voice suddenly remembered: "Professor Wu, you just said that there is a way to improve a new pre-cooling plan. What is the plan?"

Wu Chunmin was slightly stunned and said, "There is another way, which is to discharge pre-cooling. Before the engine starts and under normal pressure, open the front valve and pre-cooling discharge valve. Under the pressure of the tank, the low-temperature propellant flows through the front pipeline and the pump, and finally discharges from the pre-cooling discharge valve in front of the propellant main valve. Since the propellant is discharged in a large flow rate in a short time, it needs to be added before injection to supplement the low-temperature propellant consumed by pre-cooling. In this way, not only will the waste of propellant be much more than the circulating pre-cooling, but there are still several problems with the emission pre-cooling."

“What’s the problem?”

"The first problem is that the discharge pre-cooling requires hundreds of kilograms of liquid oxygen to discharge in a very short time (about 5 minutes), and the storage tank must be replenished before injection. The discharge of a large amount of liquid oxygen requires some corresponding pipelines and ground treatment equipment. On the contrary, the liquid consumption of circulating pre-cooling is generated in three hours. The entire process is continuous and there will be no special operations before injection because of pre-cooling. Moreover, the liquid oxygen used for pre-cooling returns to the storage tank and discharges only the gas-phase components, so there is no need for special ground treatment and pipeline equipment. Therefore, the use of circulating pre-cooling energy will greatly simplify the pre-injection operation and ground equipment. The second problem is that the low-temperature propellant has been filled for a long time after the ground filling pipe. The second problem is that the low-temperature propellant has been filled with a long time.

During the road, the external heat flow is absorbed to increase the temperature, and the high-temperature propellant enters the storage tank, causing the overall propellant temperature to rise and the quality of the propellant decreases. To reach the temperature we expected, there must be an extremely accurate mathematical model for the weight of the propellant emitted. The problem is that the 921 rocket adopts a cyclic pre-cooling method. If we want to temporarily change it to an emission pre-cooling, then it needs to perform very complex calculations. Now there is only more than two hours left to close the launch window. Apart from other pre-launch preparations, it is only less than an hour left to do theoretical calculations. It is impossible for us to complete such complex calculations in such a short time."

Pang Xuelin said: "Does there be emission pre-cooling treatment equipment?"

At this time, the launch commander-in-chief Wang Yu interrupted and said, "This is true. Our launch tower has prepared several systems according to different rockets. If the 921 rocket wants to use emission pre-cooling, the launch tower can provide supporting equipment."

Pang Xuelin smiled faintly and looked at Wang Yu and said, "Commander Wang, can you let me try it? Within half an hour, I will complete the amount of liquid oxygen discharged for emission pre-cooling, and the launch program will continue to be promoted simultaneously."

"Half an hour?! Professor Pang, are you sure?"

Wang Yu frowned and hesitated.

Liu Xuesong, Tao Yongchang and others also looked at Pang Xuelin with shock.

Wu Chunmin frowned involuntarily. He knew very well how terrifying the calculation amount required for the pre-cooling system was. In the process of pre-cooling calculation, it is inevitable to solve the two-phase flow.

The main models for calculating and analyzing two-phase flow are homogeneous models, phase separation models and slip flow models. Among these models, the homogeneous model is the least difficult and the slip flow model is the most difficult. The emission pre-cooling uses the slip flow model. Even if you have a complete mathematical model and use the computer, it will take at least one to two days to complete such calculations, but Pang Xuelin said that he is sure to complete it within half an hour. How is this possible?!

Several other big guys who understand the complexity of pre-cooling calculations have similar ideas to Wu Chunmin, but they did not object.

On the one hand, Pang Xuelin's reputation is too big.

The Nobel Prize in Chemistry and Fields Special Prize have almost carried him to an unprecedented level, and it is an insurmountable peak in the Chinese academic community.

On the other hand, it is the achievements made by Pang Xuelin.

It is natural to say that the super problems in mathematics are super difficult. Even in the field of engineering, lithium air batteries, carbon nanomaterials, room temperature superconducting materials, etc., each of them has a very significant impact on the current global industrial system. Superconducting materials are even expected to allow Pang Xuelin to win the Nobel Prize in Physics again next year.

Therefore, since Pang Xuelin said that he was sure, no matter how doubtful the people were in their hearts, they could not directly object.

And they also want to see if this big guy's level is as good as the legendary one.

Soon, the staff in the command hall found the banknotes for Pang Xuelin.

Pang Xuelin picked up the banknotes and asked Wu Chunmin about the parameters of the circulation pre-cooling system while quickly calculating on the manuscript paper.

Liu Xuesong, Wu Chunmin, Wang Yu and others came behind Pang Xuelin one by one, wanting to see the big guy's calculation ideas.

But soon, they gave up.

Because Pang Xuelin's calculations on manuscript paper are like books of heaven. Not to mention those who are engaged in aerospace engineering, even a professional mathematician can't figure out the formulas written by Pang Xuelin on manuscript paper for a while.
Chapter completed!