What is the quantitative relationship between water mist particle size and dust collection efficiency in a cyclone spray dust collector?
Publish Time: 2026-02-18
As a fusion of dry cyclone dust collection and wet scrubbing technologies, the cyclone spray dust collector significantly enhances its ability to collect fine particulate matter by introducing water mist into the rotating airflow. Its core lies in the interaction between water droplets and dust particles, a process highly dependent on the particle size distribution of the water mist. The water mist is neither necessarily better the finer it is, nor the coarser the better; rather, there exists an "optimal particle size window" that matches the target dust particle size.1. Collection Mechanism: Particle Size Coupling Effect Dominated by Inertial CollisionIn a cyclone spray dust collector, the dust-laden airflow enters the cylinder tangentially, forming a high-speed rotating flow field. After being sprayed through the nozzle, the water mist rapidly migrates towards the wall under centrifugal force, simultaneously interacting with the radially moving dust particles. The main collection mechanism is inertial collision: when dust particles, due to inertia, cannot bypass the water droplets with the airflow, they are captured by the water droplets. The efficiency of this process is closely related to the Stokes number of the water droplets and dust particles—Stk reflects the particle's ability to deviate from streamlines and is proportional to the square of the particle diameter. Therefore, the droplet size directly affects its "interception cross-section" and collision probability. Theoretically, the collision efficiency is highest when the water droplet diameter is approximately 10–50 times the dust particle size.2. Particle Size Matching: Optimal Water Mist Range for Different Dust ScalesFor coarse particles, traditional cyclone separation is already highly efficient, with the water mist primarily serving to suppress dust and prevent back-mixing. In this case, larger water droplets can be used to reduce evaporation loss and enhance wall wetting. However, for fine particles, due to their strong tracking ability and low inertia, more precise control is required. Experiments show that when the average diameter of the water mist sauter is controlled within 30–80 μm, the PM2.5 collection efficiency can reach over 85%. If the water droplets are too fine, the number concentration is low, the total surface area is small, and the collision opportunities per unit volume decrease, thus reducing efficiency.3. Quantitative Model: Functional Relationship between Efficiency and Particle SizeThe efficiency of the cyclone spray dust collector increases with the product of water droplet and dust particle size, but a saturation point exists. CFD-DEM coupled simulation further shows that, under a fixed liquid-to-gas ratio, the dust removal efficiency first increases and then decreases with the water mist SMD, exhibiting a single-peak curve. The peak position shifts to the right as the median dust diameter shifts to the right. This provides a theoretical basis for precise "mist matching based on dust" design.4. Engineering Optimization: Coordinated Control of Nozzle Selection and Operating ParametersIn practical applications, different types of nozzles are selected to control the water mist particle size. High-pressure recirculation nozzles can produce 30–60 μm fine mist, suitable for fine dust; low-pressure spiral nozzles generate 80–150 μm water droplets, suitable for high-concentration coarse dust. Simultaneously, combined with online dust monitoring, the water supply pressure and flow rate are dynamically adjusted to achieve adaptive matching between water mist particle size and load. Furthermore, multi-stage spray arrangements can accommodate the efficient removal of dust particles of different sizes.In cyclone spray dust collectors, the relationship between water mist particle size and dust removal efficiency is not linear, but rather exists within a clearly defined physical optimal range. By understanding the inertial collision-dominated collection mechanism and combining it with quantitative models and intelligent control, high efficiency can be ensured while avoiding excessive water consumption. In the future, with the introduction of spray digitization and AI optimization algorithms, precise control of water mist particle size will further drive the technology towards high efficiency, low carbon emissions, and intelligent operation.
