CFX's latest computing power

2. Comparison between fluent and ANSYS CFX

1. Fluent was acquired by ANSYS in 2006

in the United States, finite volume method, FVM method and fluent have developed the following procts: widely used! Support C & # 92; C + + language development
fluent 6.2-a general CFD solver based on unstructured grid, the former is structured grid solver, such as version 4.5 and 5.5
the software design of FLUENT is based on the idea of CFD software group, from the perspective of user needs, aiming at various physical phenomena of complex flow, fluent software adopts different discrete formats and numerical methods, in order to achieve the best combination of calculation speed, stability and accuracy in specific fields, so as to efficiently solve the problems of complex flow calculation in various fields. Based on the above ideas, fluent has developed flow simulation software suitable for various fields. These software can simulate fluid flow, heat and mass transfer, chemical reaction and other complex physical phenomena. Unified grid generation technology and common graphical interface are used between the software. The difference between the software is only e to the different instrial background, So it is very convenient for users< GBR / > gambit is a special CFD preprocessor (geometry / grid generation). Fluent series procts use gambit preprocessor software developed by fluent company to build geometry and generate grid. It is a preprocessor with super ability to build model, and then solved by fluent< CFX was acquired by ANSYS in 2003

British finite volume method FVM method and finite volume method based on finite element. Support C & # 92; C + + language development
grid capability (fluent gambit is inferior to ICEM CFD)
accuracy (fluent is not as good as CFX, the default difference scheme of CFX is second-order, but it is difficult for fluent to converge with the second-order scheme)
reliability (fluent is not as good as CFX). By heart, CFX's coupled solver converges much faster than fluent's. That's an order of magnitude difference.)
parallel capability (fluent is not as good as CFX. These two softwares have been used to solve problems such as aircraft outflow on multi CPU clusters. Fluent is too slow.)
post processing (fluent's post-processing diagram is too rustic, compared with CFX's, it's much more beautiful and professional.)< The advantages of CFX are abundant physical models and powerful functions. The finite volume discretization method based on finite element method has high accuracy but slow calculation speed; There is a lack of fluent physical model, and there is no corresponding model for many problems. For example, each phase of multiphase flow cannot be multi-component, and multiphase flow composed of wet air and other fluids cannot be considered. Moreover, the pre processor format of FLUENT is closed, which can only be suitable for fluent, and the pre processor ICEM of CFX has rich output formats< I've used CFX for a long time, and occasionally used fluent. I know that CFX has some shortcomings, and I also know that fluent is strong in some aspects.
1. There is only one kind of full implicit solver in CFX, and there are three kinds of fluent: progressive, full explicit and full implicit.
although CFX has less iteration, it consumes a lot of memory.
2, There are many unknown functions in the UDF (user Fortran in CFX) of CFX, so it is not easy to develop complex models. The UDF (in C language) of fluent can provide relatively complete information query< The GUI of CFX is really better than that of fluent, with good pre-processing and post-processing, and good coordination. Fluent just doesn't focus on the improvement of GUI, but it can achieve the same function. Just be used to it. The focus of CFD code is to avoid mistakes and misunderstandings. Does code developer rece CFD code error as much as possible!, GUI friendliness is not the key point. Basically, the accuracy of solution has a lot to do with the user's skill. For the same software and the same problem, some people solve it wrong and some are OK.
5. There are many users of the two kinds of software, and it is not easy to integrate them into one, but they may complement each other and improve at the same time.
6, The latest academic or instry research results will probably be reflected in the solver models, which is similar.

- --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -. The efficiency of Yang Cheng calculated by these two softwares is almost the same, and the difference is 5%. This is already very big. Why? The torque calculated by FLUENT is 880, while the torque calculated by CFX is 850. It is because the torque difference is so much that the efficiency will be so poor. Why are the two CFD softwares so different when calculating the same pump? I heard some people say that CFX is more suitable for rotating machinery. Is that so? Is CFX more accurate than fluent? I hope you can give me an answer

whiz 2013-09-06 17:49
the difference of 5% between the two software results is not big<

z41906957 2013-09-13 22:56
how big is it

qianzd 2013-09-26 11:55
check your torque calculation surface, there should not be such a big gap

Rexxar 2013-09-27 03:07
5% is acceptable, if there are experimental data, compare with the actual test, In my previous experience of calculating pumps and turbines, the efficiency of FLUENT is always slightly lower than that of the experiment, while CFX is higher than that of fluent
in fact, the result of FLUENT is more conservative, and the characteristic curves calculated by the two softwares are similar
but the engineers feel that the efficiency of numerical calculation should be higher than that of the experiment It makes people think that CFX works well
and a series of software has been developed for CFX of rotating machinery for a long time, which is very convenient from pre-processing to post-processing, which also makes people in this field tend to use it
now that both of them are mastered by ANSYS, the difference should be smaller

Tianma sk 2013-09-28 11:32
listen to what you say, that is, the CF for water pump If x is calculated, the result is the closest to the experimental result? In other words, it is better to use CFX for water pump

turbulence 2013-09-30 21:04
What about grid independence? Is the model strictly consistent? Is the numerical format consistent<

Rexxar 2013-10-08 16:30
take a look at the suggestions on the sixth floor
the accuracy of the calculation results needs to be compared, and the experimental results or the recognized calculation results
I think CFX is more convenient to operate, and the calculation is good near the design condition, but some off design conditions are not very good, It depends on which one you choose.
in addition, it's not reliable to only rely on numerical calculation to obtain accurate performance parameters, whether it's fluent or CFX

3. ANSYS\ cfx\ v110\ CFX\ bin\ Postgui in WinNT_ Ogl.exe file was killed by antivirus software as a virus, and it's OK to it again and put it in which location!

4. Is the boundary with the liquid undefined

5. Go to the simulation forum! If you can't get into it, you can also see the forum behind the horse! There should be all of them! Official information can be downloaded

6.

(1) In terms of algorithm, CFX adopts the finite volume method mixed with finite element, while fluent is the pure finite volume method. From the specific use, we can realize that CFX takes up more memory than fluent, and the convergence speed is faster than fluent block, and the single step calculation time of CFX is more than fluent. Of course, this has something to do with CFX's default implicit solver

(2) in terms of the number of users, CFX and fluent are not in the same order of magnitude. In terms of coupled field calculation, CFX can be more convenient than fluent for fluid structure coupling calculation because of its hybrid finite element method

However, there are many tools (such as MpCCI) that can be used to calculate the coupling between fluent and other solid software. In workbench, CFX and ANSYS can achieve bidirectional coupling, while fluent can only achieve unidirectional coupling

(3) in terms of learning difficulty, the current course of FLUENT is much more than that of CFX. There seems to be only one tutorial for CFX, and the one that Dangdang gave back was a poor review. The course of FLUENT is flying all over the sky

The biggest difference between

and CFX is also deeply reflected in their respective codebase, that is, fluent uses cell-based volume elements, while CFX uses vertex based volume elements

The advantages of CFX are abundant physical models and powerful functions. The finite volume discretization method based on finite element has high accuracy but slow calculation speed; There is a lack of fluent physical model, and there is no corresponding model for many problems.

for example, each phase of multiphase flow can not be multi-component, and it can not be calculated for multiphase flow composed of wet air and other fluids. Moreover, the pre processor format of FLUENT is closed, which can only be suitable for fluent, and the pre processor ICEM of CFX has rich output formats< br />

7. I think: CFX is easier
the latest version is V16.2
both moles are from ANSYS company

8. In the United States, finite volume method, FVM method and fluent have developed the following procts: widely used! Support C & # 92; C + + language development
fluent 6.2-a general CFD solver based on unstructured grids, which used to be a structured grid solver, such as version 4.5 and 5.5
the software design of FLUENT is based on the idea of CFD software group, from the perspective of user needs, aiming at various physical phenomena of complex flow, fluent software adopts different discrete formats and numerical methods, in order to achieve the best combination of calculation speed, stability and accuracy in specific fields, so as to efficiently solve the problems of complex flow calculation in various fields. Based on the above ideas, fluent has developed flow simulation software suitable for various fields. These software can simulate fluid flow, heat and mass transfer, chemical reaction and other complex physical phenomena. Unified grid generation technology and common graphical interface are used between the software. The difference between the software is only e to the different instrial background, So it is very convenient for users
gambit is a special CFD preprocessor (geometry / grid generation). Fluent series procts all use gambit preprocessor software developed by fluent company to build geometry and generate grid. It is a preprocessor with super combination ability to build model, and then solved by fluent< CFX was acquired by ANSYS in 2003

British finite volume method FVM method and finite volume method based on finite element. Support C & # 92; C + + language development
grid capability (fluent gambit is inferior to ICEM CFD)
accuracy (fluent is not as good as CFX, the default difference scheme of CFX is second-order, but it is difficult for fluent to converge with the second-order scheme)
reliability (fluent is not as good as CFX). By heart, CFX's coupled solver converges much faster than fluent's. That's an order of magnitude difference.)
parallel capability (fluent is not as good as CFX. These two softwares have been used to solve problems such as aircraft outflow on multi CPU clusters. Fluent is too slow.)
post processing (fluent's post-processing diagram is too rustic, compared with CFX's, it's much more beautiful and professional.)< The advantages of CFX are abundant physical models and powerful functions. The finite volume discretization method based on finite element method has high accuracy but slow calculation speed; There is a lack of fluent physical model, and there is no corresponding model for many problems. For example, each phase of multiphase flow cannot be multi-component, and multiphase flow composed of wet air and other fluids cannot be considered. Moreover, the pre processor format of FLUENT is closed, which can only be suitable for fluent, and the pre processor ICEM of CFX has rich output formats< I've used CFX for a long time, and occasionally used fluent. I know that CFX has some shortcomings, and I also know that fluent is strong in some aspects.
1. There is only one kind of full implicit solver in CFX, and there are three kinds of fluent: progressive, full explicit and full implicit.
although CFX has less iteration, it consumes a lot of memory.
2, There are many unknown functions in the UDF (user Fortran in CFX) of CFX, so it is not easy to develop complex models. The UDF (in C language) of fluent can provide relatively complete information query< The GUI of CFX is really better than that of fluent, with good pre-processing and post-processing, and good coordination. Fluent just doesn't focus on the improvement of GUI, but it can achieve the same function. Just be used to it. The focus of CFD code is to avoid mistakes and misunderstandings. Does code developer rece CFD code error as much as possible!, GUI friendliness is not the key point. Basically, the accuracy of solution has a lot to do with the user's skill. For the same software and the same problem, some people solve it wrong and some are OK.
5. There are many users of the two kinds of software, and it is not easy to integrate them into one, but they may complement each other and improve at the same time.
6, It will probably reflect the latest academic or instry research results to solver models

9. Grid capability (fluent gambit is inferior to ICEM CFD); Accuracy (fluent is not as good as CFX, the default difference scheme of CFX is second-order, but it is difficult for fluent to converge when using second-order scheme); Reliability (fluent is not as good as CFX. By heart, CFX's coupling solver converges much faster than fluent. At that time, the order of magnitude is different.) parallel ability (fluent is not as good as CFX. It used these two kinds of software to calculate aircraft outflow and other problems on multi CPU clusters, but fluent is too slow.) post processing (fluent's post-processing diagram is too rustic, compared with CFX's beautiful and professional.) each has its own advantages and disadvantages, The advantages of CFX are abundant physical models and powerful functions. The finite volume discretization method based on finite element has high accuracy, but slow calculation speed; There is a lack of fluent physical model, and there is no corresponding model for many problems. For example, each phase of multiphase flow can not be multi-component, and it can not be calculated for multiphase flow composed of wet air and other fluids. Moreover, the format of fluent's preprocessor is closed, which can only be suitable for fluent. The ICEM output format of CFX's preprocessor is rich, I know that CFX has some shortcomings, and I also know that fluent is strong in some aspects. 1. CFX has only one kind of fully implicit solver, and fluent has three kinds of solutions, which are graded, fully explicit, and fully implicit. Although CFX has less iteration, it consumes a lot of memory. 2. CFX's moving grid is my worst problem, which is simply pulling the grid, Fluent is obviously powerful in this aspect. 3. The UDF (user Fortran in CFX) of CFX has many unknown functions and is not easy to develop complex models. The UDF (in C language) of fluent can provide relatively complete information query. 4. The GUI of CFX is really better than that of fluent, with good pre and post-processing strings and enough coordination. Fluent just doesn't focus on the improvement of GUI, However, they can all achieve the same function. Just get used to it. The focus of CFD code is not easy to make mistakes and misunderstandings. Code developer has tried to rece CFD code error!, GUI friendliness is not the key point. Basically, the accuracy of solution has a lot to do with the user's skill. For the same software, the same problem, some people solve wrong, some are OK. 5, It will probably reflect the latest academic or instry research results to solver models

10. The full name of SLI is scalable link interface (also known as speed), which is a patented technology of NVIDIA. It is connected through a special interface, on a motherboard that supports al PCI Express x 16, and uses two same model of PCI e graphics cards at the same time. In order to enhance the competitiveness of NVIDIA in workstation procts, after all, ATI has been eating into the market of NVIDIA in this field with the FireGL series. In the future proct line, SLI will become the new highest point
hybrid crossfire, the English name of hybrid crossfire, is the interpretation of Hybrid Graphics hybrid graphics technology. We can plug the independent graphics card supporting hybrid crossfire into the 7 series integrated motherboard which also supports hybrid crossfire to build a hybrid crossfire system. When we need to carry out high-load computing, Independent graphics card and integrated graphics card will work at the same time to achieve the best display performance. When the computing demand is reced, only integrated graphics card can be used, plus AMD's cool & # 39; n' With quite technology, the power consumption of the whole platform will be reced to the lowest point, which meets the requirements of people for the rational use of energy
in the field of graphics card technology, "hybrid" is a new technology concept. From the perspective of application value, both NVIDIA's hybrid SLI and AMD's hybrid crossfire bring direct and effective performance to the graphics card, making the system more efficient, more energy-saving and quiet application environment. From the perspective of the development direction of graphics card technology, both NVIDIA's hybrid SLI and AMD's hybrid crossfire have great market significance
the so-called hybrid SLI (non hybrid switching, two similar concepts) refers to a new hybrid SLI technology proposed by NVIDIA, which can interconnect the display chip on the motherboard with the graphics card, rece the power consumption and heat, so as to achieve the purpose of quiet PC operation
in many PC applications, users do not need high-performance independent GPU, and NVIDIA's hybrid SLI technology has this control and management function. This technology combines NVIDIA graphics processor (GPU) and SLI multiple GPU technology, and has built-in geforce boost and hybrid power two new technologies. Geforce boost is responsible for the collaborative operation of NVIDIA on-board GPU and NVIDIA independent graphics card. In 3D games and multimedia applications, geforce boost can automatically add graphics processor jobs to improve program execution efficiency and picture update rate; Hybrid power can provide "high efficiency" and "low power" operation modes. The high performance mode is that the GPU core and independent graphics card run at the same time, which can significantly improve the overall performance of the platform in large-scale 3D complex computing. For example, in 3D games, image processing and other software needs, to turn on the efficient mode, the on-board GPU core and independent graphics card constitute SLI mode, which can enhance graphics efficiency, improve efficiency and save time. If the user turns on the low-power operation mode, the hybrid SLI platform will turn off the independent graphics card and only use the GPU core to run the output display, which can effectively rece the power consumption and heat. The first mock exam is not only useful for indivial users, but also helps the owners of Internet cafes to minimize power consumption and save a large part of their expenses.