喷水推进船舶边界层影响系数的计算方法研究

Study of a method for calculating boundary layer influence coefficients of ship and boat propelled by water-jet

针对喷水推进船舶的边界层影响系数难以计算的问题,提出了一种基于积分运算的边界层影响系数计算方法。将边界层影响系数作为变量处理,通过求解推进泵吸收功率与发动机功率的平衡方程,得到了喷水推进系统的流量,基于流量的连续性定理,计算出喷水推进系统的有效进流厚度。以有效进流厚度为边界条件进行积分运算,最终推导了边界层影响系数的解析计算表达式。通过对某型喷水推进船舶的边界层影响系数进行校核,并通过仿真得到了边界层影响系数在一定推进功率下随速度的变化规律,验证了所提方法的正确性和有效性。

Aiming at the problem that the boundary layer influence coefficients of waterjet propulsion ship are difficult to calculate, a method based on integral operation is proposed. The boundary layer influence coefficients are dealt with as a variable in this method. By solving the balance equation of propulsion pump absorbed power and engine power, the water flow of propulsion system is obtained. Then the value of effective inlet thickness of waterjet propulsion system is calculated based on the theorem of flow continuous. Through integral operation, treating the effective inlet thickness as the boundary condition, the analytical calculation expressions are ultimately derived. The boundary layer influence coefficients of certain waterjet propulsion ship are checked, and the trend of which under a certain power changing with ship speed is simulated to verify the correctness and effectiveness of this method.