效应是指物体辐射的波长因为光源和观测者的相对运动而产生变化，在运动的波源前面，波被压缩，波长变得较短，频率变得较高，在运动的波源后面，产生相反的效应，波长变得较长，频率变得较低，波源的速度越高，所产生的效应越大，根据光波红/蓝移的程度，可以计算出波源循着观测方向运动的速度，恒星光谱线的位移显示恒星循着观测方向运动的速度，这种现象称为多普勒效应。 The Doppler ultrasonic flowmeter effect means that the wavelength of an object's radiation changes due to the relative movement of the light source and the observer. In front of a moving wave source, the wave is compressed, the wavelength becomes shorter, the frequency becomes higher, and the Behind the wave source, the opposite effect occurs. The wavelength becomes longer and the frequency becomes lower. The higher the speed of the wave source, the greater the effect. According to the degree of red / blue shift of the light wave, the wave source can be calculated to follow the observation direction. The speed of the movement, the displacement of the star's spectral line shows the speed of the star moving in the observation direction, this phenomenon is called the Doppler effect. The Doppler effect is not only applicable to sound waves, it is also applicable to all types of waves, including light waves and electromagnetic waves. Scientist Edwin Hubble uses the Doppler effect to conclude that the universe is expanding. He found that the frequency of light rays in the distant galaxy is increasing, that is, moving toward the red end of the spectrum. This is the red Doppler shift, or redshift. If the Milky Way is moving towards him, the light becomes blue shifted ...
测量原理 First, the measurement principle of Doppler ultrasonic flowmeter
The Doppler ultrasonic flowmeter uses the acoustic Doppler principle to measure liquid flow, which can measure multiphase flow (fouling liquids, such as municipal sewage, industrial wastewater, crude oil, oil-water mixture, mud, pulp, pulp, juice, etc.), and It can measure single-phase flow (pure liquid, such as tap water, river water, seawater, chemical liquid, etc.), and has a wide range of applications. When measuring multiphase flow, because the liquid contains reflective particles such as bubbles, solid particles, suspended matter, etc., the Doppler signal is a relatively narrow frequency band velocity. When it is a certain average value (sufficient straight pipe section can ensure its velocity More stable distribution), you can get higher measurement accuracy. When measuring single-phase flow, the liquid contains fewer reflective particles. At this time, compared with the Doppler signal when measuring multi-phase flow, there is a big difference. Generally, when a clean liquid flows through an elbow, tee, or half-open valve, the flow velocity distribution is turbulent and turbulent, which is called a turbulent state; when passing through a straight pipe section, the flow rate tends to stabilize. In this way, the interface is generated during the turbulent to stable flow. This interface is called the pressure interface or the shear wave interface. Near the elbow, tee, half-open valve, etc. (1 to 2 times the length of the inner diameter of the pipe), the speed of this interface is unstable. When leaving the elbow, tee, half-open valve, etc. (4 to 5 times the length of the inner diameter of the pipe), the interface flow rate is basically the same as the average flow velocity of the fluid. When leaving more than 10 times the length of the inner diameter of the pipe, this interface disappears and becomes a stable flow velocity distribution. When measuring single-phase flow, the measurement point can be selected at a length of 4 to 5 times the inner diameter of the pipeline. At this time, the Doppler signal can be obtained at the pressure interface. However, this signal is weak and the frequency band is wide. It is necessary to make a special spectrum analysis circuit and amplifying operation circuit to ensure the measurement accuracy of the Doppler ultrasonic flowmeter when measuring single-phase flow.
主要应用领域[（a）行业，（b）目的] 2. Main application fields of Doppler ultrasonic flowmeter [(a) industry, (b) purpose]
(A) Sewage treatment plant
(B) Flow measurement at water inlet and outlet and intermediate links
(2) Crude oil
(B) Crude oil, oil-water mixture and oily sewage flow measurement.
(3) Sodium aluminate solution
(A) Aluminum plant
(B) Process flow measurement that cannot be measured by other flowmeters such as sodium aluminate solution
(4) Industrial water and drainage
(A) Steelmaking, ironmaking, chemical, pharmaceutical, papermaking and other plants
(B) Inspection of pump power, effective distribution management of flow in each process, and measurement of total discharge outlet
(5) Various pulp liquids
(A) Pulp and paper mill
(B) Flow management, proper replacement of pumps to reduce power costs.
(6) Coal / ore mixed water
(B) Flow measurement during coal preparation / dressing
(7) Sugar solution, starch solution
(A) Sugar factory, starch factory
(B) Processes applicable to edible pipes
(8) Water for cooling water and air-conditioning equipment, warm water
(A) Construction, building construction, maintenance of buildings
(B) Flow management and efficiency check
(9) Various processing fluids
(A) Chemical, pharmaceutical, and pharmaceutical factories
(B) Flow measurement at high / low temperature and high pressure
(10) Debris mixed water
(A) Construction company
(B) Flow measurement when sand, rocks, etc., which are the main seabed, are transported on a pump
(11) Rivers, sea water, salt water
(A) Chemical, food, pharmaceutical, petrochemical, salt factories
(B) Flow rate measurement mainly for cooling water and treated brine
(12) Clear water
(A) Electronic equipment manufacturing plant, chemical plant, semiconductor plant
(B) Measurement of fresh water flow
(13) Working oil
(A) Ironmaking, construction machinery, manufacturing plants
(B) Inspection and management of engine oil for switching on and off of large unloading trucks, and inspection and management of power lubricants for construction machinery.
(14) Cutting oil
(A) Automotive and related industry work machinery plants
(B) Flow rate distribution, inspection and management of working machine cutting oil.