Stand of Material INTRODUCTION3 Method: 3 Component 23 Component 33 Component 44 Portion 54 RESULTS4 Part 13 Part 21 Part thirty-six Part 46 Part five: 6 DISCUSSION7 CONCLUSION7 REFERENCES7 INTRODUCTION The primary objective on this assignment should be to simulate a 3-D air flow in a pipe using Ansys CFX. The pipe was simulated underneath specific circumstances. These conditions are atmosphere temperature to become 25? C (degrees Celsius), one atmospheric reference pressure, no temperature transfer and laminar circulation.
The comes from the simulation of alisar flow in the pipe were compared with the theoretical kinds.
Also the mesh was refined in the simulation to verify that it is possible to get additional accurate results using grid convergence evaluation. Method: The pipe employed in the ruse has proportions of a zero. 5m axial length and a radial diameter of 12mm. Mid-air entering the pipe, inlet velocity, is set to zero. 4 m/s at a temperature of 25? C and a single atmospheric pressure. No slide condition was set on the pipe wall space. The outlet of pipe was set to absolutely no gauge typical static pressure. In CFX a nylon uppers was formed around the pipe using a default nylon uppers spacing (element size) of 2mm.
Determine (1) and (2) shows the setup of the version before ruse was preformed Figure 1: Mesh with out Inflation Determine 1: Nylon uppers without Pumpiing Figure a couple of: Mesh with Inflation Part 2 Calculating the pressure drop? p=fLD? Ub22Equation (1) Calculating Reynolds number Re=UbD/? Equation (2) Friction Factorf=64/ReEquation (3) The results were worked out using exceed, and drawn in Figure (3). Part 3 Price the entry pipe span Le: Le/D=0. 06ReEquation (4) Having Re=UbD/? Equation (3) The lab-created results of velocity vs . axial duration were drawn in Number (5).
From the graph the Le (entrance pipe length) was dependant upon estimating the purpose in the x-axis where the competition is direct horizontal range. Part 4 Comparison of the radial distribution of the axial velocity inside the fully created region in the simulated model against the next analytical equation: UUmax = 1-rr02 Equation (5) The results were determined using excel, and drawn in Number (4). Portion 5 The simulation was performed 3 times, each time with a different main grid setting. The numbers of nodes were 121156, 215875 and 312647 for the 1st, subsequent and 3rd simulation.
BENEFITS Part 1 Figure three or more: Pressure Syndication vs . Axial Length Determine 3: Pressure Distribution versus Axial Size Figure 4: Axial Speed vs . Great Diameter Determine 5: Velocity vs . Axial Distance Portion 2 Having: Dynamic viscosity? = 1 . 835, 10-5 kg/ms and Density? sama dengan 1 . 184 kg/m3 Reynolds Number Re=UbD? == 261. 58 Scrubbing Factorf=64Re== zero. 244667? p=0. 965691 Pennsylvania From the ruse the pressure estimated with the inlet is? p=0. 96562 Pa (0. 95295-0. 965691)/0. 965691*100 = 1 . 080 % Component 3 Having Re=UbD? =261. 58 The entrance water pipe length Votre: Le=0. 06Re*D = 0. 188 m
From the graph in Determine (3) the Le is estimated to be ~ zero. 166667 ((0. 166667-0. 188)/0. 188)*100 sama dengan 11. 73% Part four From the graph in Figure 2 the theoretical velocity at the center in the pipe is usually estimated to be 0. almost 8 m/s. From your simulation the speed at the center with the pipe can be estimated being 0. 660406 m/s. ((0. 688179-0. 8)/0. 8)*100= 13. 98% Part 5: Table 1: Percentage Error for Each Simulation Number of Nodes| Central Velocity % error (%)| Pressure % error (%) | 120000 Simulated I| 13. 98| 1 . 31| 215000 Lab-created II| doze. 42| installment payments on your 24| 312000 Simulated III| 12. 38| 2 . 28|
Figure six: Percentage Error vs . Volume of Nodes Determine 6: Percentage Error vs . Number of Nodes The percentage error for the axial speed results from the first, 2nd and 3rd simulation were calculated and plotted in Figure (6), plus the pressure result along the tube. Table (1) shows the axial velocity and pressure percentage error for each ruse. DISCUSSION After the simulation was successfully performed on Ansys CFX plus the simulated results were compared with theoretical results, it had been found the fact that simulated results have slight deviation coming from theoretical ones. In PART a couple of, he pressure in the simulated result differed by the theoretical by a 1 . 080%, to get 1st simulation. In PART several, the controlled results pertaining to entrance water line length, Le, differed from your theoretical outcomes by eleven. 73%. In PART 4, Determine (4), the simulated speed curve is much less accurate than that of the theoretical. Partly 5, meshing refinements and inflation had been done to the simulation in order to getting better results. Figures (6) show with additional nodes and inflation the accuracy with the results improves. Increasing the nodes little by little was located to be a benefit where bigger or more correct results were acquired.
This is mentioned in main grid convergence chart, Figure (6), as the amount of nodes raise the pressure percentage error is converging to 2% and for velocity percentage error can be converging to 12%. However, the percentage error increased together with the increase from the number of nodes while the velocity error decreased with the maximize of number of nodes. Simply 2 the percentage error to get pressure drop is 1 ) 080%, to get 1st ruse. But when trying to increase the reliability of the lab-created velocity result by improving the meshing and adding nodes the pressure drop percentage problem increases, because shown in figure (6).
This is due to that Darcy-Weisbach formula, equation (1), assumes continuous developed movement all over the pipe wherever in the controlled results the flow is definitely observed for being developed daddy down the pipe from the inlet. This is presumed to change the pressure division along the water pipe. CONCLUSION Even more nodes employed in meshing is going to produce more accurate and precise results, while shown in Figure (6). Also the meshing performs a vital guideline on the tenderness of ends in terms of the accuracy of these results. REFERENCES Smooth Mechanics Outspoken M. White-colored Sixth copy. 2006