Geometric characteristic number
R (Radius) is the distance from the center point of the compressor air outlet (or turbine air inlet) cross section of the turbine bearing center channel (the turbine radius line is wound 360 degrees, that is, a circle). A (Area) refers to the cross-sectional area of the air outlet of the compressor housing (or the air inlet of the turbine housing) corresponding to the above center point. The ratio of A divided by R is the A/R value.
In addition: in chemistry, it means analytical purity. Generally speaking, there is chemical purity, but the purity of analytical purity is higher, which is generally used for refining, analytical chemistry, etc.
AR Interpretation ：
AR value The first online marketing capability evaluation activity for college students was exclusively provided with bonus, prize support and online marketing practice projects of some small commodity enterprises by China Small Commodity City Network, a subsidiary of Zhejiang China Small Commodity City Group. The activity was named "China Small Commodity City Cup College Students" Network marketing ability show ”。 Sina.com, as an exclusive co organizer, provides support for online promotion resources such as blog marketing, and the management consultant of new competitive online marketing provides technical consultants and the operation and maintenance of the official website of college students' online marketing ability show. The first China Commodity City Cup online marketing ability show for college students was officially launched on June 19, 2009. The college students' online marketing ability show is one of the projects of "Internet Application Training to Promote Employment Project" of Internet Association of China, which is mainly aimed at learning network marketing The relevant majors of the course are college students, and further extended through holiday online marketing practice activities Network Marketing Theory The teaching content combined with practice is to exercise college students' online marketing application ability through practical activities and play a positive role in improving the employment success rate of graduates, including the communication and direct employment opportunities between college students and enterprises provided by the support unit China Commodity City Group, the promotion of the event's official website and support media to college students participating in the event Self network promotion under the guidance of experts and teachers. The A/R value is divided into compressor A/R value and turbine A/R value.
Generally speaking, the higher the A/R value of the compressed air is, the more suitable it is for the turbine with low turbocharging value. However, the A/R value of the compressed air is small, which is more suitable for the turbine with high supercharging value. However, relatively speaking, the change of compressor A/R value has little effect on turbine performance.
The turbine A/R value at the exhaust end is very important. The lower the A/R value, that is, the higher the exhaust gas flow rate, the faster the turbocharging response of the turbine in the low speed region, and the lower the turbine hysteresis, the higher the turbocharging in the low speed region. But at the same time, the smaller the A/R value, the greater the exhaust back pressure, the insufficient exhaust gas flow at high speed, and the limited high RPM.
In contrast, the higher the A/R value, the worse the response of the turbine in the low speed region. Although the turbocharging of the engine at low speed is difficult to increase, it can generate more power in the high speed region. The tendency of high speed and high output is quite clear.
In a word, a small A/R value is a low torque turbine, while a large A/R value is a high rev and high output turbine.
