﻿ 烟囱热排烟对舰船甲板风下洗影响的大涡模拟
 舰船科学技术  2016, Vol. 38 Issue (11): 34-38 PDF

Large eddy simulation to the effect of smoke from power device to downwash of wind over flight deck of warship
YUAN Shu-sheng, ZENG Liang, ZOU Qiang
Naval Aeronautical and Astronautical University, Yantai 264001, China
Abstract: The control equations of air flow with lower Mach number and the large eddy simulation method of turbulent flows are used to study the effect of the heat smoke from the power device on the downwash of the wind over deck of warship under the condition of the head-on wind. The variety process of three components of velocity of air motion with time is conducted at some positions in the upper space over the flight deck. To compare without the heat smoke the heat smoke depresses the time-averaged downwash speed and advance the pulse downwash speed at the position over the flight deck. At the positions over the flight deck with the same distance to the door of garage the more near to the bow-stern plane the effect of the heat smoke on the downwash flow is more distinct. The closer the position is to the stern the less the effect of the heat smoke on downwash is.
Key words: warship     large eddy simulation     effect of smoke from power device     wind over deck
0 引言

1 大涡模拟控制方程组

 $\bar{p}\left( x,t \right)={{\bar{p}}_{0}}\left( z \right)+\tilde{p}\left( x,t \right)$ (1)

 ${T_0}\left( z \right) = {T_a} + \varGamma z\text{，}$ (2)
 $\frac{{{\rho _0}\left( z \right)}}{{{\rho _\infty }}} = \exp \left( { - \frac{g}{{R{T_0}}}z} \right)\text{，}$ (3)
 ${\bar p_0} = {\rho _0}R{T_0}\text{。}$ (4)

 $\frac{{\partial \bar \rho }}{{\partial t}} + \nabla \cdot \bar \rho \tilde {\boldsymbol{u}} = 0 \text{，}$ (5)
 $\bar \rho \left( {\frac{{\partial \tilde {\boldsymbol{u}}}}{{\partial {\boldsymbol{t}}}} + (\tilde {\boldsymbol{u}} \cdot \nabla \tilde {\boldsymbol{u}})} \right) + \nabla \bar p = \bar \rho {\boldsymbol{g}} + \nabla \cdot {\bar {\boldsymbol{\tau}} _l} + \nabla \cdot {\boldsymbol{\tau}} \text{，}$ (6)
 \begin{aligned} \displaystyle\frac{\partial }{{\partial t}}(\bar \rho {C_p}\tilde T) \!+\! \nabla \! \cdot\! (\bar \rho \tilde {\boldsymbol{u}}{C_p}\tilde T)\! =\! \frac{{{\rm D}\bar p}}{{{\rm D}t}} \!+\! \nabla \cdot (\lambda \nabla \tilde T) \!+\! \nabla \cdot {\boldsymbol{q}}\text{。} \end{aligned} (7)

 $P = \frac{{{{\left| {\tilde {\boldsymbol{u}}} \right|}^2}}}{2} + \frac{{\tilde p}}{{\bar \rho }}\text{，}$ (8)
 $\begin{array}{l} \displaystyle\frac{{\partial \tilde {\boldsymbol{u}}}}{{\partial t}} = \tilde {\boldsymbol{u}} \times \tilde {\boldsymbol{\omega}} + \frac{1}{{\bar \rho }}[(\bar \rho - {\rho _0}){\rm{g}} + \nabla \cdot {\boldsymbol{\tau}} ] + \\[8pt] \quad \quad \tilde p\nabla \left( {\frac{1}{{\bar \rho }}} \right) - \nabla P\text{，} \end{array}$ (9)
 $\begin{array}{l} \displaystyle\nabla \cdot \tilde {\boldsymbol{u}} = \frac{1}{{\bar \rho {C_p}\tilde T}}\left[ {\nabla \cdot (\frac{{{\mu _T}{C_p}}}{{Pr}}\nabla \tilde T) - \tilde {\boldsymbol{u}} \cdot \nabla \left( {\bar \rho {C_p}\tilde T} \right)} \right] + \\[10pt] \quad \quad \quad \left( {\displaystyle\frac{1}{{{{\bar p}_0}}} - \frac{1}{{\bar \rho {C_p}\tilde T}}} \right)w{\rho _0}g\text{，} \end{array}$ (10)
 $\begin{array}{l} {\nabla ^2}P = - \displaystyle\frac{\partial }{{\partial t}}\left( {\nabla \cdot \tilde {\boldsymbol{u}}} \right) + \nabla \cdot \left\{ {\tilde {\boldsymbol{u}} \times \tilde {\boldsymbol{\omega}} + \frac{1}{{\bar \rho }}[(\bar \rho - {\rho _0}){\rm{g}}} \right. + \\ \quad \left. {\begin{array}{*{20}{c}} {} & {} \end{array}\nabla \cdot {{\bar {\boldsymbol{\tau}} }_l} + \nabla \cdot {\boldsymbol{\tau}} ] + \tilde p\nabla \left( {\displaystyle\frac{1}{{\bar \rho }}} \right)} \right\}\text{，} \end{array}$ (11)

2 模拟对象与工况参数

 图 1 计算区域与舰船模型示意图 Fig. 1 The sketch map of simulated region and modeled ship

3 结果分析与讨论

 图 2 飞行甲板后方某处的压强 Fig. 2 The calculated pressure of air at the point after the flight deck

 图 3 飞行甲板上方首尾对称面上距离机库较近位置的下洗速度 Fig. 3 The calculated down-wash velocity of air flow at the point over the flight deck closer to the garage and on the ship bow-stern symmetrical plane

 图 4 飞行甲板上方首尾对称面上距离机库较近位置的航向与横向速度 Fig. 4 The calculated course and landscape velocities of air flow at the point over the flight deck closer to the garage and on the ship bow-stern symmetrical plane

 图 5 飞行甲板上方舷侧附近位置的下洗速度 Fig. 5 The calculated down-wash velocity of air flow at the point over the flight deck closer to the shipboard

 图 6 飞行甲板上方舷侧附近位置的航向与横向速度 Fig. 6 The calculated course and landscape velocities of air flow at the point over the flight deck closer to the shipboard

 图 7 飞行甲板上方艏艉对称面上舰尾附近位置的下洗速度 Fig. 7 The calculated down-wash velocity of air flow at the point over the flight deck closer to the stern and on the ship bow-stern symmetrical plane

 图 8 飞行甲板上方首尾对称面上舰艉附近位置的航向与横向速度 Fig. 8 The calculated course and landscape velocities of air flow at the point over the flight deck closer to the stern and on the ship bow-stern symmetrical plane
4 结语

1）较无热烟气排出，热排烟使飞行甲板上方的下洗速度时均值减小，其脉动幅度增加；

2）飞行甲板上距离机库门相同的位置上，越靠近艏艉对称面，热排烟对下洗速度的影响越大；

3）越靠近舰尾区域，热排烟对飞行甲板风下洗速度的影响越小。

 [1] 邵开文, 马运义. 舰船技术与设计概论[M]. 北京: 国防工业出版社, 2009 : 748 . [2] HEALEY J V. The Aerodynamics of ship superstructures[C]//Proceedings of AGARD Conference-aircraft Ship Operations., AGARD-CP-509, 1991. [3] POLSKY S A. A computational study of unsteady ship airwake[C]//AIAA 2002-1022, 40th AIAA Aerospace Sciences Meeting & Exhibit. Reno, Nevada: AIAA, 2002. http://www.oalib.com/references/17311430 [4] REDDY K R, TOFFOLETTO R, JONES K R W. Numerical simulation of ship airwake[J]. Computers & Fluids , 2000, 29 (4) :451–465. [5] VAN MUIJDEN J, BOELENS O J, VAN DER VORST J, et al. Computational ship airwake determination to support helicopter-ship dynamic interface assessment[C]//AIAA 2013-3078, 21st AIAA Computational Fluid Dynamics Conference, Fluid Dynamics and Co-located Conferences. San Diego, CA: AIAA, 2013. [6] SYMS G F. Simulation of simplified-frigate airwakes using a lattice-Boltzmann method[J]. Journal of Wind Engineering and Industrial Aerodynamics , 2008, 96 (6/7) :1197–1206. [7] REHM R G, BAUM H R. The equations of motion for thermally driven, buoyant flows[J]. Journal of Research of the National Bureau of Standards , 1978, 83 (3) :297–308. DOI:10.6028/jres.083.019 [8] DEARDORFF J W. Numerical investigation of neutral and unstable planetary boundary layers[J]. Journal of Atmospheric Sciences , 1972, 29 (1) :91–115. DOI:10.1175/1520-0469(1972)029<0091:NIONAU>2.0.CO;2 [9] DEARDORFF J W. Stratocumulus-capped mixed layers derived from a three-dimensional model[J]. Boundary-layer Meteorology , 1980, 18 (4) :495–527. DOI:10.1007/BF00119502 [10] WERNER H, WENGLE H. Large-eddy simulation of turbulent flow over and around a cube in a plate channel[C]//Proceedings of the 8th Symposium on Turbulent Shear flows. Berlin Heidelberg: Springer, 1991, 34: 155-168. [11] MCGRATTAN K, HOSTIKKA S, MCDERMOTT R, et al. Fire dynamics simulator (version 6)-technical reference Guide[M]. NIST Special Publication 1018, 2013. [12] MCGRATTAN K, HOSTIKKA S, MCDERMOTT R, et al. Fire dynamics simulator (Version 6)-user's guide[M]. NIST Special Publication 1019, 2013. [13] MCGRATTAN K, HOSTIKKA S, MCDERMOTT J, et al. Fire dynamics simulator (version 6) technical reference guide volume 3: validation[M]. NIST Special Publication 1018, 2013.