应用Fluent的UDF二次开发对某隧道安全通风进行设计(3)
In general, any kind of software can not meet the requirements of each individual. Fluent, too, its standard interface and function can not meet the needs of each user. UDF is used to solve problem, we can use it to write FLUENT code to meet the special needs of different users.
1. custom boundary conditions , defining material properties, surface and volume defined response rate, defined Fluent transport equation in the source term, user-defined scalar transport equation (UDS) in the source term diffusion rate function , etc ;
2. In each iteration based on the calculated adjustment value;
3. Program initialization;
4 UDF asynchronous executions;
5 to improve the post-processing function;
6. Fluent model improvements (such as discrete binomial model, a number of the mixture model, discrete emission radiation model).
In this paper, numerical simulation method study the long highway tunnel in central event of 50MW fire, after determining the opening three exhaust port and exhaust port spacing is 60m program for the optimal solution on the basis of the basic
Through Fluent in UDF port custom variable cross-section distribution of material properties, which can achieve the flue gas flow simulation. Application of Fluent UDF interface to the original program on the secondary development, in order to get more optimized models.
UDF is the Fluent software provides a user interface, the user can use it with Fluent module's internal data exchange, which can solve some standard Fluent modules can not solve the problem. To sum up , UDF can solve several problems: handling the boundary conditions ; modify the source term ; define material properties ; variable initialization ; surface and volume reaction rate ; dealing with a number of flow -related issues ; dynamic mesh movement defined ; through introduce additional equation UDS
Fluent have a powerful data processing capabilities, we carry through this port UDF personalized settings and special simulation needs. So that we can get a more optimized data setting. As the text of the data processing, define calculated velocity u = 0.1 * y * (0.001-y) / (0.0005 * 0.0005) and calculate the temperature of u = 0.8 / y to improve accuracy of the results. In the future we can get better design，we can according to the environmental conditions of fire, weather factors and affect of human.
From this we can draw the following conclusions: Because Fluent simulation and analysis of fluid flow is carried out under ideal conditions, if we calculate the results according to their tunnel ventilation design, the design program will be too idealistic. Meanwhile, we can also know the relevant source code is written there is a certain degree of difficulty, can not possibly be compiled every time calculations. Therefore, we have adopted a compromise approach set aside five percent each rooms this is calculated via the fluent basis to this scale factor multiplied by 0.95.
Such ventilation design in the future, we design a security will be greatly enhanced.
Key words: Extraordinary long highway tunnel; Fire; Numerical simulation; Fluent；UDF
目 录
1绪论 1
1.1研究目的与意义 1
1.2国内外研究现状 2
1.2.1国外研究现状 3
1.2.2国内研究现状 3
1.3公路隧道火灾的原因与特点 4
1.4公路隧道火灾通风的主要研究方法 5
2公路隧道火灾通风的计算流体力学理论与数值模拟方法 7
2.1公路隧道火灾通风的基础理论 7
2.3．CFD数值模拟方法 9
2.4. UDF在Fluent中的应用 11
3 火灾时某特长公路隧道纵向通风数值模拟 13
3.1 某特长公路隧道设计概况 13
3.2 计算模型的建立 13