Chapter 1180 Terminal Precision Guidance


    The overall design of the warhead has been a division of labor undertaken by Chang Haonan on behalf of the Aerospace Power Group from the very beginning.


    Although the mission was neither aeronautical nor powered, apparently no one would question his ability in the field of aerodynamic design.


    Not to mention the powerful First Institute of Aerospace Science and Technology to assist.


    Therefore, during this period of time, everyone''s focus was basically on other parts such as power, guidance, control and testing processes.


    It wasn''t until this interruption from the Fifth Academy that the topic was brought back to the warhead.


    "Sweating cools down..."


    The warm atmosphere in the conference room calmed down slightly, and many people lowered their heads again and started thinking -


    The technical term proposed by Chang Haonan is not new.


    The cooling fluid first flows through the porous wall and carries out forced convection heat transfer to remove the heat, and then forms a dense air film on the surface of the wall to reduce the heat transfer of the high-temperature mainstream to the wall.


    If a liquid coolant is used in this process, it will be very similar to the sweating and heat dissipation process of animals, which is why sweat cooling is named after it.


    Its characteristic is that it includes both active and passive heat exchange principles. At the same time, the surface air film formed after the cooling fluid seeps out of the porous wall has an excellent adhesion effect. Even if only the passive insulation effect is considered, it is better than simple air film cooling. .


    But as a price, sweat cooling requires special porous materials as carriers, and has extremely high requirements on microporous structure, thermal conductivity, processing technology and heat resistance.


    Both the design difficulty and cost remain high.


    "Academician Chang...isn''t this a bit overkill?"


    Li Rongwei asked in a somewhat uncertain tone:


    "Sweat cooling is generally used on the tail nozzle of rocket engines to withstand gas temperatures above 3500K... Our verification projectile is only 6-7 times the speed of sound at the end. Even if it is calculated based on the sea level throughout the journey, aerodynamic heating It’s not to this extent, right?”


    After speaking, he turned his head to look at the representative of the Sixth Academy who specialized in this.


    The latter, who was suddenly cueed, didn''t react at first, but then he nodded:


    "This is indeed true... Judging from our experience, with current technology, the highest efficiency of sweat cooling can already be of the order of 10^9W/m^2... used in a double cone, and the speed can reach Mach 10 It’s really overkill for places that can’t be reached.”


    "Furthermore, the perspiration cooling of the nozzle part is usually done directly with liquid fuel, so that the vaporized part can be burned directly. If this process is to be realized in the warhead part, an additional layer of porous material is needed to prevent it. Not only does the thermal layer serve as the base, additional coolant flow channels need to be designed, which will inevitably have an impact on the overall strength of the double cone..."


    From a project management perspective, the biggest risk of this kind of verification bomb is not actually the number of separate new technologies added.


    After all, even if something goes wrong, as long as the specific cause can be found, you can still roll back the state if it doesn''t work.


    The more serious risk is that the entire system becomes more and more complex for some reason.


    Once something goes wrong, it may cause the gourd to float when pressed.


    Just like a mountain of **** code, after the bug is fixed, the entire program cannot run normally.


    Therefore, in the few hours of meeting just now, the only thing that increased the complexity of the system was to change the originally planned warhead counterweight into a terminal acceleration engine.


    But this is still a relatively independent part. Even if the engine fails to start, it will not have an impact on the previous propulsion system.


    Sweat cooling needs to be highly coupled with the power system, which is inherently risky. From a performance perspective, it does not seem to have such a high heat release requirement.


    So their concerns are justified.


    But like the double cone, it has been one of the basic plans determined by Chang Haonan from the beginning, and it is obviously impossible to change it just because of two sentences:


    "I understand your concerns... That''s why I just said that the early-stage air-breathing lofts that are actually put into use in the future should still return to the traditional passive cooling route." He first gave a relatively positive answer, but it was not too tight. Then the conversation changed:


    "But ours is a verification bomb after all, and it is not used to play an actual tactical role, so we need to have a certain degree of foresight and consider all possible situations that may arise in the future of the entire project."


    "In the future, our hypersonic weapons may use infrared or visible light bands for target guidance. The biggest drawback of the ablation and heat protection design is that the ablation products will flow down the gas boundary layer, causing a boundary layer Contamination is likely to enter the window area of ??the vision sensor, causing the loss and attenuation of the homing information. "


    "In addition, at the speed of Mach 6-7, because the thickness and intensity of the ionosphere are relatively small, there is a high probability that there is no need to consider the issue of electromagnetic shielding. However, for faster flying objects in the future, it is necessary to actively use ion currents to deal with The plasma sheath wrapped around the outside of the flying body needs to be weakened and modified to allow radar waves of a specific band, specific phase and incident angle to penetrate the shielding layer and detect the target with radar. This and the requirement of sweating cooling are at a certain point. Similar to some extent..."


    “…”


    Having said this, Chang Haonan suddenly stood up, turned off the PPT that was just used for the meeting background, and then opened a new document.


    Above is a dizzying array of formulas.


    Of course, even if everyone here is an expert, it is impossible to understand these contents immediately without preparation.


    But everyone can still understand the series of pictures mixed in between the formulas -


    Several different types of remote sensing satellites'' radar imaging effects of targets such as large ships, cities, ports, and airports.


    Obviously, what Chang Haonan refers to as "radar detection" is not simply receiving reflected echoes like early anti-ship missiles, and then picking the largest one and piercing it.


    Instead, SAR imaging is used to accurately identify targets within the search range.


    It was only then that everyone present suddenly realized that the goal of Academician Chang in front of them was much longer-term than they initially thought...


    At least it''s not just a matter of tossing out a hypersonic weapon that''s fast enough.


    After letting everyone digest it for a while, Chang Haonan spoke again:


    "Some comrades here...especially comrades from the Aerospace Science and Technology Group may know that in the past few years, I was fortunate enough to participate in the development of imaging algorithms for the two remote sensing satellite systems, Ziyuan-2 and Haiyang-1."


    "After that, although a new generation of remote sensing satellites are still under development and there is no specific launch timetable, my research team and I have not stopped technical research on image segmentation and target contour tracking."


    "So far, we can basically detect large surface ships with special contour features in the ocean background, and identify landmarks or buildings with special shapes in the land background where the terrain is not very complex..."


    At this time, someone from below suddenly answered:


    "Like the Pentagon?"


    This question was obviously a bit clever, but it relaxed the atmosphere of the scene just right.


    A happy atmosphere suddenly filled the conference room.


    After laughing, Chang Haonan nodded:


    "Although this metaphor may not be appropriate, if we only consider it from a technical perspective, it is indeed the most perfect goal..."


    There was another burst of laughter that was slightly sparser than before.


    “Actually, a more commonly used function of this algorithm may be to accurately identify towers, hangars and runways within an airport, or to identify the most valuable target ships in a port... In addition, if special Ground-penetrating radar can also identify bunkers or warehouses hidden underground.”


    He continued in a slightly bewitching tone:


    "Of course, the more complex the actual situation is, the greater the amount of calculations required to identify the target. Considering that the terminal period of hypersonic weapons is very short, the missile-borne computer at this stage may not be able to achieve too precise requirements."


    "But I believe that one day in the future, we will use this technology..."


    (End of chapter)