Influence Of An Inner Cylinder On The Rectangular Capillary Occlusion

Capillary action is a common phenomenon in nature and in productive life.With the refinement and miniaturisation of many products,capillaries containing fluids inside may become occluded,affecting the performance of the product or system.This paper investigates the effect on the occlusion performance of a rectangular capillary filled with liquid,inserted into a cylinder under the influence of transverse external force,using the existence theorem and mathematical determination formulae for the occlusion of a capillary menicus by Concus et al.The results of the study are.(1)The critical Bond number was chosen as the parameter to determine whether the capillary is occluded or not,and the curve between the Bond number and the contact angle after the insertion of a cylinder in a rectangular capillary was calculated.The corresponding criteria are defined: if the Bond number is greater than the critical Bond number in a certain situation,the capillary will not be occluded,i.e.it is empty;if the Bond number is less than the critical Bond number in a certain situation,the capillary may be occluded.(2)The effect of the size and contact angle of the concentric cylinder inserted in the rectangular capillary on the occlusion of the rectangular capillary was investigated,and a graph between the Bond number and the contact angle was obtained,as well as two possible topographies.When the contact angles of the cylinder and rectangular walls are equal,increasing the size of the inner cylinder can significantly reduce the critical Bond number,i.e.weaken the possibility of capillary occlusion;when the contact angles of the cylinder and rectangular walls are unequal,for the same cylinder,the minimum critical Bond number is obtained when the difference between the inner and outer contact angles is the largest.(3)The effect of the size and contact angle of the eccentric cylinder inserted in the rectangular capillary on the occlusion of the rectangular capillary was analyzed,and a plot between the Bond number and the contact angle was obtained,together with four possible topologies.For the vertical eccentric circle combination tube,increasing the eccentricity increases the maximum value of the critical Bond number,but the minimum value also decreases,and the minimum value is obtained at 135° when the eccentric circle is vertical upwards and at 45° when it is vertical downwards;for the horizontal eccentric circle combination tube,increasing the eccentricity does not change the maximum value of the critical Bond number,the minimum value gradually decreases,and the Bond number curve is symmetric about 90°.