'Computional Fluid Dynamics Through a Pipe\r'

' remand of Contents presentation3 Method:3 fraction 23 Part 33 Part 44 Part 54 RESULTS4 Part 14 Part 26 Part 36 Part 46 Part 5:6 DISCUSSION7 CONCLUSION7 REFERENCES7 INTRODUCTION The main objective of this assignment is to put on a 3-D air catamenia in a shrill victimization Ansys CFX. The tubing was reproduce under circumstantial conditions. These conditions are air temperature to be 25? C (degrees Celsius), one atmospheric extension rack, no heat transfer and stratified flow. The results from the example of laminar flow in the thermionic vacuum tube were compared with the divinatory ones. likewise the meshing was splendid in the simulation to see if it is possible to get much finished results utilize grid convergence analysis. Method: The pipework used in the simulation has dimensions of a 0. 5m axial space and a stellate diameter of 12mm. The air entering the pipe, niche stop number, is set to 0. 4 m/s at a temperature of 25? C and one atmospheric embrace. No mooring condition was set on the pipe walls. The outlet of pipe was set to cypher gauge average static jam. In CFX a mesh was formed on the pipe with a default mesh spacing (element size) of 2mm. understand (1) and (2) shows the setup of the model in the first place simulation was preformed elaborate 1: take without Inflation forecast 1: date without Inflation Figure 2: mesh with Inflation Part 2 collusive the pressure drop ? p=fLD? Ub22 equation (1) calculating Reynolds number Re=UbD/? Equation (2) brush Factorf=64/ReEquation (3) The results were work out using excel, and plot in Figure (3). Part 3 Estimating the hitch pipe length Le: Le/D=0. 06ReEquation (4) Having Re=UbD/? Equation (3) The faux results of velocity vs. axial length were plotted in Figure (5).From the graph the Le (entrance pipe length) was determined by estimating the point in the x-axis where the curve is honest horizontal line. Part 4 proportion of the radial distribution of the axial veloci ty in the fully positive locality in the bogus model against the chase analytical equation: UUmax = 1-rr02 Equation (5) The results were calculated using excel, and plotted in Figure (4). Part 5 The simulation was performed trine times, each time with a antithetical grid setting. The numbers of nodes were 121156,215875 and 312647 for the world-class, 2nd and tertiary simulation.RESULTS Part 1 Figure 3: Pressure dissemination vs. axile length Figure 3: Pressure Distribution vs. axile Length Figure 4: Axial Velocity vs. Radial diam Figure 5: Velocity vs. Axial Distance Part 2 Having: driving viscosity ? = 1. 835×10-5 kg/ms and assiduousness ? = 1. 184 kg/m3 Reynolds Number Re=UbD? == 261. 58 Friction Factorf=64Re== 0. 244667 ?p=0. 965691 Pa From the simulation the pressure estimated at the inlet is ? p=0. 96562 Pa (0. 95295-0. 965691)/0. 965691*100 = 1. 080 % Part 3 Having Re=UbD? =261. 58 The entrance pipe length Le: Le=0. 06Re*D = 0. 188 mFrom the graph in Figure ( 3) the Le is estimated to be ~ 0. 166667 ((0. 166667-0. 188)/0. 188)*100 = 11. 73% Part 4 From the graph in Figure 2 the theoretical velocity at the center of the pipe is estimated to be 0. 8 m/s. From the simulation the velocity at the center of the pipe is estimated to be 0. 660406 m/s. ((0. 688179-0. 8)/0. 8)*100= 13. 98% Part 5: Table 1: dowery geological fault for Each Simulation Number of Nodes| Axial Velocity % illusion (%)| Pressure % mistake (%) | 120000 Simulated I| 13. 98| 1. 31| 215000 Simulated II| 12. 42| 2. 24| 312000 Simulated III| 12. 38| 2. 28|Figure 6: Percentage mistake vs. Number of Nodes Figure 6: Percentage Error vs. Number of Nodes The part mistake for the axial velocity results from the 1st, 2nd and third simulation were calculated and plotted in Figure (6), as well as the pressure result along the pipe. Table (1) shows the axial velocity and pressure percentage fault for each simulation. DISCUSSION by and by the simulation was successfully done on Ansys CFX and the simulated results were compared with theoretical results, it was found that the simulated results have slight deviation from theoretical ones. In PART 2, he pressure in the simulated result differed by the theoretical by a 1. 080%, for 1st simulation. In PART 3, the simulated results for entrance pipe length, Le, differed from the theoretical results by 11. 73%. In PART 4, Figure (4), the simulated velocity curve is less accurate than that of the theoretical. In PART 5, meshing refinements and largeness were done to the simulation in shape to getting better results. Figures (6) show with more nodes and inflation the accuracy of the results maturations. Increasing the nodes gradually was found to be an advantage where higher(prenominal) or more accurate results were obtained.This is far-famed in grid convergence graph, Figure (6), as the number of nodes increase the pressure percentage actus reus is converging to 2% while for velocity percentage error is conv erging to 12%. On the former(a) hand, the percentage error increased with the increase of the number of nodes while the velocity error decreased with the increase of number of nodes. In Part 2 the percentage error for pressure drop is 1. 080%, for 1st simulation. provided when trying to increase the accuracy of the simulated velocity result by nuance the meshing and adding nodes the pressure drop percentage error increases, as shown in count (6).This is due to that Darcy-Weisbach equation, equation (1), assumes constant developed flow all along the pipe where in the simulated results the flow is observed to become developed father implement the pipe from the inlet. This is assumed to change the pressure distribution along the pipe. CONCLUSION more than nodes used in meshing result produce more accurate and minute results, as shown in Figure (6). Also the meshing plays a vital chemical formula on the sensitivity of results in terms of the accuracy of these results. REFERENC ES [1]Fluid Mechanics Frank M. sinlessness Sixth edition. 2006\r\n'