Messerschmidt was in awe: "This is wonderful! I think that if the M40 and M20 transport planes can use this turboprop engine, the performance will be greatly improved! The development of a jet engine is a very large and complex project, and it is not easy to develop a usable jet engine! It's impossible to do it in ten or eight years, right? ”

Philip looked at the crowd with resolute eyes: "Mr. Messerschmidt is very right, but don't be discouraged! It is very difficult to develop an aero turbine engine, but as long as we all work together, we will definitely be able to build our aero turbine engine! I thought about it, and we will develop a non-afterburner jet engine with a thrust of about 1,500 kg, and the engine weight is controlled below 700 kg! At the same time, the development of the same type of turboprop engine, the power can reach about 2000 horsepower, M40 transport aircraft with 2 turboprop engines, can replace 4 BMW 715 horsepower piston engine, the power is even greater. ”

Billy was surprised: "Ah, in this way, the performance of the M40 transport aircraft has been improved again!" ”

Philip nodded and continued, "Yes! The working process of a jet engine is a non-stop cycle of inhalation, compression, combustion, expansion and jet. The pressure, temperature, flow and other parameters of each component of the engine and the section of the flow channel require a large number of tests and calculations, and the overall scheme design of the jet engine starts from the extremely important and extremely tangled project of selecting the cycle parameters. The selection of these parameters is also very particular, and I think it can be compared to finding a balance on a tightrope! ”

When Messerschmitt heard this, he sighed: "Yes! Designers are sometimes too idealistic, but they have to succumb to reality and make certain trade-offs in various performances! Philip, hurry up and come up with a development plan! With the plan, we can quickly put it into development! I would also like to achieve mass production of jet engines as soon as possible. ”

Looking at everyone's expectant expressions, Philip said, "Okay! When it comes to the design of aero engines, it's like a mother-in-law choosing a son-in-law! If this jet engine wants to live with the aircraft in his mind, he must first let the aircraft user or the mother-in-law of the aircraft manufacturer choose! ”

Philip stopped and looked at many young people present, and said with a smile: "This mother-in-law chooses a son-in-law, there are a few requirements, have a lot of strength, eat less, don't pick a child at every turn, it's best to be open all year round, if you are sick, you can take a pill without going to the hospital, and at the same time, you must be calm and restrained enough and pay attention to hygiene." Put it here for this aircraft user and manufacturer, it is required to have high thrust, fuel efficiency, high reliability, easy maintenance and low cost, good applicability, and high combustion efficiency! So it's really not easy to get the mother-in-law to choose! ”

Everyone couldn't help but laugh when they heard it, and they all covered their stomachs and laughed!

Philip said: "In fact, before the blind date, the group of relatives and friends had already received more specific requirements from the mother-in-law, that is: you don't have much career now, but you should be capable, you can't be too big in life, you must be able to live, and you can't be too short or too tall, and you can't be a big fat man." In addition, the body must be healthy, and you can't go up to the fifth floor in one breath and not meet a ditch in work and life, and you can't easily lose confidence...... Etcetera. That is, there are several requirements for the engine: thrust, fuel consumption, size, weight, no surge, and no stalling under harsh conditions. The conditions are clear, everyone quickly writes them down, the name is the son-in-law's enlistment book, ah no, it is the general requirement of research and development - young man, let's fight hard! ”

Billy laughed so hard that he couldn't breathe, clutched his stomach and said, "Mr. Philip, you have such a good sense of humor. Then you can talk about the design of this jet engine in a more understandable way, and we can learn from it! ”

Philip laughed and said, "Okay, then I'll start with the fluid mechanics of jet engines." Speaking of ability, why is the jet engine so fierce? Here we must start with the equation of state of the gas, and this magic equation is PV=RT. Having mastered the gas equation of state, the air molecules are not yet arbitrarily rounded and flattened by us, obediently accepting enslavement. Here's the thing, in the air around us, there are countless naughty air molecules. According to the different temperaments and temperaments, they are divided into various types such as nitrogen molecules, oxygen molecules, and water molecules. These molecules are like billiard balls that have been broken up by a single pole, constantly in motion and colliding with each other. When something gets in the way of their progress, they hit it hard. It's okay to meet other air molecules, but it's a big deal that everyone changes directions and continues to run forward. If you encounter solid elements lined up to meet the enemy, it will be an immediate reflection of the fate. Of course, at this time, the solid molecules of the copper wall were also hit the waist. ”

Everyone listened with great joy, and even Messerschmidt, who had never been smiling, could not help but laugh up and down.

Philip continued: "The molecules are too small, and the force of a collision is certainly not worth mentioning. But there are too many of them, and hundreds of billions of molecules collide with them all the time. So from a macro point of view, any object in the air will be continuously subjected to a pressure, which is the air pressure P. Speaking of this name, there is really a reason, the surface area of each component inside the engine and the area of each runner section are generally fixed, if every time the pressure is calculated by the pressure multiplied by the area, it is too stupid, so just throw away the area, the pressure is the pressure! ”

Billy laughed, "That's right! Then the pressure and the volume of the gas should be inversely proportional, right? ”

Philip smiled, "Billy is right. Obviously, the magnitude of this pressure is directly proportional to the number of molecules that collide per unit of time. The same number of air molecules stuffed into boxes of different sizes will have different pressures on the walls of the boxes. The larger the box, the more sparse the molecules, the fewer molecules that hit the same place, and the less stress. Specifically, the pressure P is inversely proportional to the volume V of the gas. As long as the temperature is constant, the pressure must be reduced by half when the volume is doubled, but the product of the two is always the same. ”

Billy said with understanding: "Then the jet engine should be similar to the piston engine, and the gas pressure is proportional to the temperature, right?" ”

Philip looked at Billy with appreciative eyes and said, "In the same way, the more active the molecules, the greater the speed, and the greater the force of the impact. However, the weight of air molecules is high or low, and the speed of collision is also very different, how do you know that this mass of gas is more active than that one? This is called average kinetic energy. As long as the average kinetic energy of the gas molecules increases, we can consider the impact force to be stronger on average. Pressure is the macroscopic manifestation of the force of a large number of microscopic molecules, so the average value is completely sufficient, and it is not necessary to know the specific situation of a certain molecule. Because the mass of a single molecule is so small, the value of the average kinetic energy is also very small, and it is still not so convenient to use. So we invented another quantity to represent the average kinetic energy, which is the temperature T. To put it simply, temperature is a representation of how hot or cold an object is. When the temperature rises, the greater the impact force of the molecules, the greater the pressure of the gas. ”