空气动力学学报
空氣動力學學報
공기동역학학보
ACTA AERODYNAMICA SINICA
2014年
5期
660-667
,共8页
常士楠%王超%赵媛媛%李延
常士楠%王超%趙媛媛%李延
상사남%왕초%조원원%리연
粗糙度%水膜%水珠%细流%结冰
粗糙度%水膜%水珠%細流%結冰
조조도%수막%수주%세류%결빙
roughness%film%beads%rivulet%ice accretion
通过对结冰表面液态水的受力分析,确定了水膜、水珠和细流特征粗糙度的大小及其之间的界限划分,发展和完善了结冰表面的粗糙度模型,开发了耦合该粗糙度模型的多步结冰计算程序;利用该程序计算结冰表面的粗糙度大小和分布特征,并对粗糙度影响下的流动和换热特性进行了计算分析;研究发现,结冰表面的粗糙度在分布是不均匀的,且随着结冰温度的降低,局部粗糙度的最大值降低,但在整个结冰过程中,局部粗糙度的最大值表现出增加的趋势;粗糙度的存在增强了结冰表面的对流换热。
通過對結冰錶麵液態水的受力分析,確定瞭水膜、水珠和細流特徵粗糙度的大小及其之間的界限劃分,髮展和完善瞭結冰錶麵的粗糙度模型,開髮瞭耦閤該粗糙度模型的多步結冰計算程序;利用該程序計算結冰錶麵的粗糙度大小和分佈特徵,併對粗糙度影響下的流動和換熱特性進行瞭計算分析;研究髮現,結冰錶麵的粗糙度在分佈是不均勻的,且隨著結冰溫度的降低,跼部粗糙度的最大值降低,但在整箇結冰過程中,跼部粗糙度的最大值錶現齣增加的趨勢;粗糙度的存在增彊瞭結冰錶麵的對流換熱。
통과대결빙표면액태수적수력분석,학정료수막、수주화세류특정조조도적대소급기지간적계한화분,발전화완선료결빙표면적조조도모형,개발료우합해조조도모형적다보결빙계산정서;이용해정서계산결빙표면적조조도대소화분포특정,병대조조도영향하적류동화환열특성진행료계산분석;연구발현,결빙표면적조조도재분포시불균균적,차수착결빙온도적강저,국부조조도적최대치강저,단재정개결빙과정중,국부조조도적최대치표현출증가적추세;조조도적존재증강료결빙표면적대류환열。
It′s recognized that the roughness dimension and distribution on the icing surface influence the flow structure in the boundary layer and thus the heat transfer characteristics is affected further.Therefore, constructing an appropriate roughness model becomes a strong requirement in order to predict the ice shape accurately.In the current work,a local roughness model was developed based on the mechanical analysis of the liquid water on the icing surface.The proposed roughness model is characterized by film,beads and rivu-let.The boundaries between film,beads and rivulet are defined according to the experimental observations in references.The set of transient governing equations developed were solved numerically with the finite vol-ume method using a computational fluid dynamics (CFD)code.The mathematical model can be used to ana-lyze the effect of different icing conditions on the roughness and thus the characteristics of the heat transfer in the icing process can be obtained.Numerical results are presented to show the applicability of the developed model and can be helpful to understand the icing mechanism further.In addition,the multi-step ice predic-ting code developed in this work can be applied in anti/deicing system design directly.The predictions show that the roughness distribution on icing surface is non-uniform,and the maximum roughness is decreasing with temperature decreases.However,during the whole icing process,the maximum roughness performs an increasing trend.The convective heat transfer was enhanced due to the roughness on icing surface.