I Am the President of the University

Latest website: (Note: The numerical modeling competition mentioned here is not taken from this year, but last year's topic. There is more information about last year on the Internet, so I will take the 2019 numerical modeling competition)

Question A has three questions in total.

Questions 1 and 3 also have two short questions. To summarize, they are:

(1) When the pressure in the high-pressure oil pipe is stable at 100 MPa, how to set the opening time of the one-way valve each time? The pressure in the high-pressure oil pipe increases from 100 MPa to 150 MPa, and stabilizes at 150 MPa after an adjustment process of about 2s, 5s and 10s respectively. How should the opening time of the one-way valve be adjusted?

(2) Under the conditions of the number of injector operations, the size of the high-pressure oil pipe and the initial pressure given in question 1, determine the angular velocity of the cam so that the pressure in the high-pressure oil pipe is as stable as possible at about 100 MPa.

(3) On the basis of question 2, add another fuel injector. Each nozzle has the same fuel injection pattern. How should the fuel injection and fuel supply strategies be adjusted? Please provide the control scheme for the high-pressure oil pump and pressure reducing valve.

To solve the problem, you must first analyze it based on the problem. Analysis is not difficult for Lu Zhou.

It didn't take a while to finish analyzing the topic.

[Question 1. The problem defines a constant oil outlet method. At the same time, the oil inlet method defined is only related to the system pressure and the opening time of the one-way valve. Secondly, it was proposed...]

[Question 2: This question redefines the oil inlet and outlet method. At this time, the oil inlet method will be related to the angular velocity of the cam. This requires us to re-describe the oil inlet and outlet method based on question 1 and set the decision variables... 】

[Question 3: This question is based on question 2. A new fuel injector is added to the system. As a result, the oil delivery method will change. Because whether the fuel injection time of the newly added fuel injector is consistent with...]

Next, clarify your ideas for doing the questions, and then start dividing the work. Solve problem modeling, search literature, prepare paper templates, and write programs.

"Zhang Lei, please go to CNKI to check some documents for me, and prepare a paper template."

Lu Zhou continued without raising his head, "Old Zheng, please familiarize yourself with the topic first. After I build the model, you can prepare to program."

The two nodded and stood ready.

Just then, there was a knock on the door.

The three of them looked at the door and saw Chen Hao standing there.

Chen Hao walked in with three cups of Starbucks in his hand and smiled.

"Classmates, how's it going? Is the question difficult?" After saying that, Chen Hao put the coffee on the table and said with a smile: "Drink some coffee to refresh yourself. I also ordered takeout of Kaifeng cuisine for you. I'll pick it up later." It’s coming.”

"Thank you, principal!" Zhang Lei stepped forward and distributed the coffee with a happy face.

Zheng Tianyu, on the other hand, scratched his head in embarrassment and said, "Principal, this is costing you too much."

Now in this classroom, not only is a three-tatami bed laid out in the corner, but also a box of barreled instant noodles, Red Bull, and snacks are stacked on one side.

This preparation made the three of them feel really warm.

I also made up my mind to achieve a good result.

"It's okay, the competition is important, let me take a look at the questions." Chen Hao said with a smile, sitting in the seat given by Zhang Lei, looking at the questions on the screen.

I finished reading it in a short time, and I also had some drafts in my mind.

During the competition, you are not allowed to discuss the topic with the instructor or outsiders, so Chen Hao cannot help them.

Zheng Tianyu looked at Chen Hao curiously and asked, "Principal, do you think this question A is difficult?"

"It's okay, it's pretty simple. But I can't teach you. Come on, let me see how Lu Zhou solves the problem first." Chen Hao finished speaking easily, stood up and stood behind Lu Zhou.

Lu Zhou was waving on the A4 paper with one hand. There were more and more formulas on the blank paper. While calculating on paper, he muttered:

"Since the pressure change of fuel is proportional to the density change, and the question also gives the relationship between the proportional coefficient changing with the former, then the fuel state equation can be obtained:

dP/dρ=E(p)/ρ, where P is the pressure and ρ is the density. "

After reciting, Lu Zhou raised his head, looked at Zheng Tianyu beside him, and said, "Old Zheng, please use software to help me calculate p(ρ)."

"Okay." Zheng Tianyu just took a sip of coffee and quickly typed on the keyboard based on the data given by Lu Zhou.

[[fitresult, gof]= createFit(p, K);

rhospan =[0.85 0.9];

p0 = 100;

[rho, p]= ode15s( @(rho, x)(1*x^6 +...

…

figure;plot(rho, p);('Fuel density('pressure p')】

As for Chen Hao on the side, the two of them were too busy to care.

After all, time is tight, only 72 hours.

Chen Hao looked at Lu Zhou's problem-solving ideas and nodded, feeling a little pleased.

"Come on, do the questions well, and remember to take a rest."

After giving the instructions, Chen Hao left directly.

And because the topic of this mathematical modeling competition was too perverted, the Internet went viral!

On journal websites such as CNKI and Wanfang, the top three most searched keywords are: airport taxi, concentric drum, and high-pressure oil pipe.

These three are the three questions in this year's mathematical modeling competition.

There is also a hot search on Zhihu, "How to evaluate the 2020 Mathematical Modeling Competition?"

Discussions on digital analog competition topics on Weibo are also becoming more and more popular.

"The menstrual period was half a month early, and the chairs in the computer room were stained with blood. It was just a good job, but none of the key issues were addressed..."

"The carnival of science and engineering schools, the lamentation of finance and economics schools!"

"I can't understand question A, I can't calculate question B, and there's no data for question C."

“I took up fluid mechanics, hydraulic transmission, and process control in one night, but I still look confused when I look at the questions.”

"From opening the topic to changing the topic, and then from changing the topic to making up..."

Peking University at 2 a.m.

Every computer in the computer room is lit up, and it seems that every participating teammate will not feel sleepy.

Although it is rumored that top academics from top universities like Tsinghua and Peking University do not like to participate in external competitions and are more interested in intramural competitions, the first place in the national competition is still very attractive.

Especially when competing for special scholarships, the resumes of top academics in prestigious schools are all full of award-winning records and journal articles...

There are seven groups of 21 people in the computer room, and each group is rubbing shoulders with each other, aiming at the Higher Education Club Cup.

The team member next to Lu Ziming asked: "Ziming, which question should we choose?"

"Choose question A." Lu Ziming said the reason calmly, "Question A is the most difficult. We are ready to start. We must win the Higher Education Society Cup this time."

The three members of the team majored in mathematics + physics + information science, and faced the high-pressure oil pipe problem with no difficulty at all.

Their opponents are...

Lu Ziming looked around at the classmates in the computer room, his eyes sharp.

As long as you defeat the classmates in the same computer room, as well as the top groups from Tongji, Nankai, Nanda, and Huake, the championship will be guaranteed!

As for other schools...sorry, they are not among the imaginary enemies.

…

"Do you think those top academics at Peking University stay up late to solve problems?" Zhang Lei yawned and looked at Zheng Tianyu.

On the table next to me, there are FamilyMart buckets of unsealed vegetables and burger wrappers.

"Maybe?" Zheng Tianyu stared at the screen and replied casually.

He didn't know if Peking University's top academics knew it. He just wanted to know if he could win the championship this time.

"Elbow, I have already completed the two programming steps for the first question."

Lu Zhou was still immersed in calculating the questions. He looked up at Zhang Lei and said, "Zhang Lei, the model and programming data for Question 1 are all handed over to you. Please write out part of the paper for Question 1 as soon as possible."

"I'm calculating problem two." Lu Zhou said, looking at the time, and continued: "I will calculate it before 6 o'clock. I plan to take a nap after calculating it."

Zheng Tianyu nodded after hearing this and said, "Okay, then I'll go to bed and sleep for a while, set the alarm clock and get up at 6 o'clock to start the programming part of the second question."

"Lao Zhang, after you finish writing part of the paper for question one, go to bed. I will wake you up after I complete the programming for question two."

Zheng Tianyu got up, exercised his muscles, and then fell asleep on the bed next to him.

The night gradually dissipates and day falls...

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I checked the information for this chapter for more than 2 hours in the early morning. I really threw up, but don’t spray water... I quickly transitioned out of it. It was too difficult to write the details.