雷诺数相似喷水推进船模预报实船推进性能

通过在数值计算中调整流体粘度系数,实现缩尺船模与实船雷诺数相似,进而消除尺度效应的影响.在弗劳德数0.15~0.41范围内,雷诺数相似船模方法预报实船阻力与模型试验外推值差别在5%以内;在波形与伴流场的比较中,雷诺数相似船模方法与实尺度计算方法预报结果基本一致.数值计算表明对于缩尺比为30的模型泵与实泵效率差别在11%~17%,而雷诺数相似模型泵效率计算值与实泵计算值差别在1.5%以内,表明通过雷诺数相似模型泵能够较好预报实泵性能.文中比较了模型雷诺数与实尺雷诺数下喷水推进器的性能变化,分析了喷水推进自航试验中可能产生的误差.通过雷诺数相似船模数值自航预报阻力、推力、推进效率与实尺度计算的比较,表明了雷诺数相似船模方法能够较好预报实尺度喷水推进船的推进性能.

Prediction of Ship Propulsion Performance Using Reynolds-Similarity Waterjet Ship Model

Fluid viscosity was adapted in numerical calculation to make model and ship’s Reynolds number similar,eliminating the scale effects.With Froude number in 0.15-0.41,the difference between the resistance predictions based on the Reynolds similarity model and full-scale data extrapolated from model measurements is less than 5%.Reynolds similarity model method and full-scale calculation method gave consistent prediction of free surface and wake field.Numerical calculation showed that the efficiency difference between pump and 1：30scale model pump was 11%-17%,while the difference between Reynolds similarity model pump and full-scale calculation was within 1.5%,showing that Reynolds similarity model pump may predict pump’s performance well.This paper compared waterjet performance in full-scale and model-scale Reynolds number,analyzing the possible errors in waterjet self-propulsion test.The resistance,thrust and propulsion efficiency predicted by Reynolds similarity model agreed quite well with that predicted by full-scale calculation,showing that Reynolds similarity model can predict full-scale waterjet propulsive performance well and is useful for engineering.