CAJ | 학술논문

根据设计参数设计了冷却塔低比转速混流式水轮机。依照水力设计尺寸绘制图纸，利用三维画图软件 Pro/ EN-GINEER 建立三维模型。基于 Realizable 湍流模型和时均 N - S 方程，对设计工况下混流式水轮机拥有不同转轮形式但蜗壳、导水机构和尾水管均不更换情况进行了数值模拟。获得了转轮内速度场、压力场的分布情况，并通过计算求得效率，对比分析了水轮机三种转轮全流道的流场分布，发现短叶片转轮在叶片背面靠近出口位置有小部分回流现象，靠近下环地方低压区域要比其他两种转轮的大，而当这个区域的压强减小到一定值时，容易发生空化空蚀。得出在合理的范围内适当增加叶片长度有利于能量的利用，并且使水轮机转轮流速、压力分布更合理，水力性能更好。
근거설계삼수설계료냉각탑저비전속혼류식수륜궤。의조수력설계척촌회제도지，이용삼유화도연건 Pro/ EN-GINEER 건립삼유모형。기우 Realizable 단류모형화시균 N - S 방정，대설계공황하혼류식수륜궤옹유불동전륜형식단와각、도수궤구화미수관균불경환정황진행료수치모의。획득료전륜내속도장、압력장적분포정황，병통과계산구득효솔，대비분석료수륜궤삼충전륜전류도적류장분포，발현단협편전륜재협편배면고근출구위치유소부분회류현상，고근하배지방저압구역요비기타량충전륜적대，이당저개구역적압강감소도일정치시，용역발생공화공식。득출재합리적범위내괄당증가협편장도유리우능량적이용，병차사수륜궤전륜류속、압력분포경합리，수력성능경호。
Low specific speed hydro turbine in cooling tower had been designed according to the design parameters. Using Pro/ ENGINEER soft-ware,it built these models referred to the drawings which drawn by CAD . Numerical simulation on three kinds of Francis turbine runner under the design condition based on model of realizable and N-S equation,all of them had same embedding part,water deflection part and draft tube. We gained velocity,pressure distribution and the efficiency of the runner and made comparative analysis of the difference among them. The calculation results show that,the velocity and pressure distribution of the runners are reasonable,but close to the edge of export on the back of short blades ap-pears backflow,and the runner with short blades has larger low pressure area than others,when the pressure in this area reaches to a level,cavitati-on is likely to happen. At last,after a series of calculating and analysis,the turbine with short blades of runner which has the lowest efficiency,so increasing the length of blades in appropriate range is benefit to the use of energy.