Analytical Prediction Model For Particle Cause Allergies Deposition Onto Ocular Surface

At present, the particle deposited velocity model can be divided into three categories. They are empirical formula model, semi-empirical formula model and probability prediction model. These models have their own characteristics, but their disadvantages are obvious. The physical meaning of empirical formula model is not explicit, and it is not very practical. The expression of semi-empirical formula model is tedious, so it causes large amount of calculation. Probability prediction model have random error caused by the uncertain factors. Therefore, this paper deduced an analytical prediction model about dimensionless deposition velocity onto ocular surface.This paper based on the definition of particle deposited velocity, and it analyzed the main factors on indoor particle that influent the deposition. After analyzing the deposition governing of particle in concentration boundary, the paper put forward prediction model of differential equation. By simplifying each item of differential equation, this paper obtained the expression of settling velocity. Finally, the paper compared numerical solution of the model with the classical experimental results to verify the reliability of the model.This paper concluded that deposition velocity onto the ocular surface fir stly decreases and then increases with the increase of the particle diameters when under low friction velocity. With the diameter of particle increasing, the deposition velocity continuously increases with the increase of the particle diameters when under relatively high friction velocity. Deposition velocity onto the ocular surface constantly increased with the increasing of the friction velocity when at the same particle diameters. The highest percentage of falling size should treat as key size of trigger allergic conjunctivitis allergen, and need to give maximum value on medicine. When indoor air movement is intense, more particles deposited on ocular surface, so it is more likely trigger allergic conjunctivitis. The new model to find the cause of allergic conjunctivitis allergens size provides a train of thought, the focus of the study of factors affecting the incidence of allergic conjunctivitis provide a theoretical reference and has the significance of interdisciplinary.The analytical method of predicted model has obvious advantages. Firstly, under the condition of guarantee accuracy, a new model simplified differential equation using the approximate formula for many times, so it not only reduce a lot of complicated formulas of input, and shorten the c alculation time of the output. Moreover, different from empirical formula and semi-empirical formula, the expression of various physical meaning is explicit, and it can avoid random errors in comparison to probability model. Secondly, when the flow field c onditions change, the empirical formula cannot help us understand the behavior of the particulate matter or predict the deposition of particles. Finally, the new model considered about thermophoresis caused by the temperature difference. Therefore, the calculation results of a new model are closer to the actual situation, so precision is improved effectively...