# Analysis of Cyclone Spinning Effect with Different Guide Vane Heights
## 3 Numerical Calculations and Validation of Results
### The Simulation Results Are Validated by Experiments  
In order to verify the simulation results of the spiral flow velocity characteristics generated by the cyclone with different guide vane heights, relevant tests were carried out. The test system consists of two parts: a PIV speed measurement system and water circulation system. The PIV velocity measurement system (Particle Image Velocity Measurement System) can obtain the water flow velocity of the measured section. In order to reduce the measurement error caused by laser refraction, a rectangular sink was installed in the test section. The water circulation system consists of six parts: a water storage tank, centrifugal pump, valve, flow meter, pipeline system, and guide vane cyclone. The overall diagram of the test system is shown in Figure 5, and Figure 6 presents a schematic diagram of the PIV speed measurement system. During the test, water was pumped into the pipeline system by the centrifugal water pump from the water storage tank, the flow rate was regulated by an electromagnetic flowmeter, and the flow field of the cyclone pipe section was measured by a PIV measuring device erected above the cyclone pipe section. Position calibration was performed on the PIV camera imaging using a calibration plate prior to measurement. A series of images carrying tracer particles were obtained by changing the height of the guide vanes of the cyclone, and the vector processing of the images was carried out to obtain the flow field information of the cyclone [29]. The cyclone flow field's characteristics were determined through Particle Image Velocimetry (PIV) measurements. Two Nd:YAG lasers, emitting at a wavelength of 532 nm, were used to illuminate the motion and interactions of particles under visible light. These lasers had a typical energy output of 120 mJ per pulse and a pulse interval of less than 1 nanosecond, which is sufficient to capture the movement of rapidly moving particles without blurring. The particles used for tracing had a size of about 10 \(\upmu\)m and a Stokes number  
Figure 5: Layout of test system. Figure 6: Speed measurement schematic of PIV. below 0.01, ensuring accurate tracking within the fluid flow. A high-resolution CCD camera, with dimensions of 1280 \(\times\) 1280 pixels, was utilized for image capture. A pulse delay generator was instrumental in synchronizing the Nd:YAG lasers with the CCD camera, facilitating the recording of fleeting particle movements. Dynamic Studio V6.8 software was employed for the processing and analysis of the images. The raw displacement vector field was derived from the PIV data using a frame-to-frame cross-correlation method. To eliminate any erroneous velocity vectors, a local median filter technique was applied. An outwardly cut rectangular tank was added to the outside of the test section of the cyclone pipe to reduce the refraction of the PIV laser in the pipe and improve the accuracy of the measurement. The guide vane is made of 5 mm thick plexiglass plate pressed on the mold, and the two sides are blackened to reduce the influence of the refraction and reflection of the laser light on the determination of the water flow rate of the test section during the test. In this study, the sources of error in PIV measurements are categorized into two types: Type I errors include calibration errors of the calibration plate and laser refraction errors, while Type II errors primarily stem from the stability of the equipment, the clarity of the images, and the quality of data processing. Type I errors originate from measurements using a calibration plate. This plate is placed inside the pipe, coinciding with the measurement area. The calibration plate measures 80 \(\times\) 80 mm and is uniformly dotted with 6400 points, each with a diameter of 1.6 mm, and a relative error of E\({}_{0}\) = 0.63%. In theory, these points should have the same area, but in actual images, the sizes of these points are not equal.