Steady-State VS Transient Propeller Numerical Simulation Comparison

     This post is about the comparison between steady-state and transient computational fluid dynamics analysis of two different propellers. The propellers under investigation are 11x7 and 11x4.7 propellers. The first number in the propeller nomenclature is the propeller diameter and the second number represents the propeller pitch, both parameters are in inch. The transient analysis was carried out using the sliding mesh technique while the steady-state results were obtained by the local rotating region-averaging method. For details about 11x7 propeller click here, for the details about 11x4.7 propeller, click here.

 

     As expected, the propeller efficiencies of transient and steady-state analysis are within 0.9% of each other, as shown in Fig. 1-2. Therefore, it is advised to simulate propellers and horizontal axis wind turbines using the steady-state technique as long as no time-dependent boundary conditions are employed.

 

Fig. 1, Propeller efficiency plot.

  

 Fig. 2, Propeller efficiency plot.

 

     It can be seen from Fig. 3-4 that time taken by the steady-state simulation to converge is on average 42.37% less that the transient analysis.  The steady-state analysis takes considerably less time to give a solution then a transient analysis.

 

Fig. 3, Solution time.

 

Fig. 4, Solution time.

 

Thank you for reading. If you would like to collaborate on research projects, please reach out.

SolidWorks Flow Simulation Premium: Propeller/Horizontal Axis Wind Turbine CFD Tutorial

The tutorial is in the attached video. Analysis such as: 11x7 Aeronautic Propeller Characteristics, 11x4.7 Aeronautic Propeller Characteristics and Wind Turbine SolidWorks Flow Simulation Premium Computational Fluid Dynamics are setup using the same method.

11x7 Aeronautic Propeller Characteristics (Using CFD) (Verified and Validated) (Update 02)

     This post presents the results from an aeronautic propeller CFD analysis.

    
     An 11x7 propeller was modelled using SolidWorks CAD package using the geometry from [1]. The simulations were run at two different rotational velocities and each rotational velocity was simulated at three advance ratios. The mesh for the 3,000 RPM rotational velocity had 213,205 total cells among which 24,048 cells were at the solid fluid boundary. While, the mesh for the 5,000 RPM rotational velocity had 369,963 total cells among which 68,594 cells were at the solid fluid boundary. A mesh control was employed to refine the mesh near the propeller geometry and at the boundary of the rotating region and the stationery domain for all of the cases simulated. This was done to ensure accuracy of the results was within an acceptable range. The results of the numerical simulations are plotted along with the experimental results [1] in Fig. 1.

Fig. 1 J= Advance Ratio, η_prop = propeller efficiency

     It can be seen from Fig. 1 that the trends for the propeller efficiency are in agreement with the experimental results. To increase the mesh density for the mesh independence test, the number of cells in  each of the respective co-ordinate directions was increased by a factor of 1.1. The mesh is shown in the Fig. 2.

Fig. 2 The computational mesh around the propeller.

     The computational domain size was at 2D x 2D x 2.4D, D being the propeller diameter, as shown in Fig. 3. In Fig. 3, the curved teal arrow represents the direction of rotation of the sliding mesh. The blue arrow represents the direction of free stream velocity while the brown arrow represents the force of gravity.

 Fig. 3 The computational domain.

Fig. 4 The pressure distribution and the velocity vectors around the propeller.

     The CAD model files and the simulation setup files for the numerical analysis are available here.

     Thank you for reading. If you'd like to collaborate on research projects, please reach out.

[1] Brandt, J. B., & Selig, M. S., “Propeller Performance Data at Low Reynolds Numbers,” 49th AIAA Aerospace Sciences Meeting, AIAA Paper 2011-1255, Orlando, FL, 2011.

doi.org/10.2514/6.2011-1255

 

Update 01

     Results from the mesh independent study are now available.

Update 02

     CAD model files are now uploaded. The CFD simulation setup files are also included.

11x4.7 Aeronautic Propeller Characteristics (Using CFD) (Verified and Validated) (Update 02)

     This post presents the results from an aeronautic propeller CFD analysis.

     An 11x4.7 propeller was modelled using SolidWorks CAD package using the geometry from [1]. The simulations were run at two different rotational velocities and each rotational velocity was simulated at three advance ratios. The mesh for the 3,000 RPM rotational velocity had 206,184 total cells among which 22,103 cells were at the solid fluid boundary. While, the mesh for the 6,000 RPM rotational velocity had 357,300 total cells among which 64,012 cells were at the solid fluid boundary. A mesh control was employed to refine the mesh near the propeller geometry and at the boundary of the rotating region and the stationery domain for all of the cases simulated. This was done to ensure accuracy of the results was within an acceptable range. The results of the numerical simulations are plotted along with the experimental results [1] in Fig. 1.

Fig. 1 J= Advance Ratio, η_prop = propeller efficiency

 

     It can be seen from Fig. 1 that the trends for the propeller efficiency are in agreement with the experimental results. The fine mesh had the number of cells in each of the respective co-ordinate directions increased by a factor of 1.1. The mesh is shown in the Fig. 2.

 

Fig. 2 The computational mesh around the propeller.

 

     The computational domain size was at 2D x 2D x 2.4D, D being the propeller diameter, as shown in Fig. 3. In Fig. 3, the curved teal arrow represents the direction of rotation of the sliding mesh. The blue arrow represents the direction of free stream velocity while the brown arrow represents the force of gravity.

Fig. 3 The computational domain.

Fig. 4 The pressure distribution and the velocity vectors around the propeller.

     The CAD model and numerical simulation setup files are available here.

 

     Thank you for reading. If you'd like to collaborate on research projects, please reach out.

     [1] Brandt, J. B., & Selig, M. S., “Propeller Performance Data at Low Reynolds Numbers,” 49th AIAA Aerospace Sciences Meeting, AIAA Paper 2011-1255, Orlando, FL, 2011.

doi.org/10.2514/6.2011-1255

 

Update 01

     Mesh independent test results are now available.

 

Update 02

     CAD files for the propeller including the CFD analysis setup are now available.

Desktop Computer Part List (Summer 2018-Pakistan Market)

     At the time of writing, 1 USD = Rs. 121.936. The prices mentioned in this post are based on the local market prices of computer components in Pakistan. Please remember that, prices vary from city-to-city within the country and shop-to-shop within a city. This is the reason why a price range is mentioned.

CPUs

     Intel Core i7-8700 for Rs. 41,500-Rs. 43,500. Top of the line processor from Intel. Always prefer a Core i7 or a Core i9 processor.

     Intel Core i5-8400 Processor Rs. 26,000-Rs. 28,000. Only buy this processor if there is a budget constraint.

Motherboard

     Gigabyte Z370 AORUS Gaming 3 for Rs. 21,200-Rs. 21,500. This motherboard has many USB ports and also comes equipped with a USB type-C port and M.2 slots etc. for future proofing.

Storage

     WD Blue 500GB Solid State Drive - WDS500G1B0A for Rs. 16,500-Rs. 17,500. Please do not buy a hard drive with rotating mechanism, it's 2018! When later in the year the SSD's prices go down, probably around November-December 2018, then buy another ~500 GB SSD. Do not waste money on a legacy hard drive.

Memory

     Corsair Vengeance LPX 16GB (1x16GB) DDR4 DRAM 3000MHz Rs. 25,800-Rs. 32,000. Please do not buy two sticks of 8 GB each. Save the remaining memory slots for future upgrading. Memory prices will fall significantly in October-November 2018 once the Chinese memory plants become operational. Don't fall for the shop keepers trickery. A common ploy employed by shopkeepers is that 1x16GB memory modules don't work in single channel mode for the 2400 MHz+ modules. It works perfectly well.

Casing

     Corsair Carbide Series® 100R Mid-Tower Case Rs.6,650-Rs. 7,500. This is the best option, really. Don't waste money on casing, it's just a box.

Power Supply

     Corsair VS550 - 550 Watt Power Supply Rs.5,800 -Rs. 6,000. A 550 Watt power supply for an i7 8700 CPU, 4 sticks of 1x16GB DDR4 memory modules, 1 SSD and up to a GTX 1x70 level graphic cards without any over clocking and 16 hours per day usage will be enough. May be this power supply will even be enough for GTX 1180 graphic card, as the graphic card chips are becoming more and more energy efficient. Yet again, do not fall for the shop keepers ploys.

Graphic Card

     Wait for the graphic new graphic cards from NVidia. The new cards are just around the corner. Local shops in Pakistan are selling 2 year old graphic cards, the GTX 10 series, at much inflated prices as compared to the rest of the world.

Conclusion

     This system will last at least 5 years, in terms of gaming with a GTX 1x70 level graphics card. It will even perform well for 10+ years if you keep upgrading it and take care of it cooling wise. Upgrade to a PCIe-NVMe SSD down the road when the prices drop, add more memory and update the graphic card every 5 years etc. Currently, the system will cost anywhere between Rs. 118,000 -Rs. 128,000, depending on you city and the shop, with an i7 processor.

     If you'd like to collaborate on research projects, please reach out. Thank you for reading.