Week 9 - Parametric study on Gate valve.

AIM: TO SIMULATE THE FLOW OF WATER THROUGH GATE VALVE AT DIFFERENT GATE OPENNINGS.

Objective:-

1. Obtain the mass flow rates at the outlet for each design point.
2. Calculate the flow coefficient and flow factor for each opening and plot the graph.
3. Discuss the results of the mass flow rate and flow coefficient.

THEORY: HERE WE WILL BE GOING AHEAD WITH k-epsilon METHOD OF SOLVING DUE TO THE FOLLOWING REASON.

The RNG approach, which is a mathematical technique that can be used to derive a turbulence model similar to the k-epsilon, results in a modified form of the epsilon equation which attempts to account for the different scales of motion through changes to the production term.

ALSO THE FLOW HERE IS TURBULANT AS RENAULT NUMBER IS GREATER THAN 2000.

STEPS TO FOLLOW FOR MODELLING AND DEVELOPING MESH FOLLOWED BY PREPROCESSING ARE GIVEN BELOW.

THE STEPS ARE AS FOLLOWS.

STEP 1- FIRST WE NEED TO OPEN SPACE CLAIM

STEP 2- THEN WE NEED TO IMPORT THE GATE VALVE STEP FILE INTO THE SYSTEM WHICH WILL GENERATE THE BODY.

STEP 3- NOW WE HAVE TO USE THE REPAIR EDGE TOOL TO REPAIR ANY DUPLICATE EDGES.

STEP 4- NOW WE NEED TO EXTRACT THE VOLUME OUT OF THIS 3 D MODEL

STEP 5- NOW WITH THE PULL COMMAND PULL THE GATE VALVE AND CLICK ON THE PARAMETER ICON .

STEP 6- ONCE DONE WE WILL SEE THAT GROUP HAS BEEN FORMED HAVING PARAMETRIC DIMENSION WHICH IS 10mm IN 1ST CASE.

STEP 7- NOW OPEN MESHING.IN MESHING WE GIVE A MESH SIZE STANDARD OF 18.47 mm AND GENERATE THE MESH. WE LIMIT THE SIZE OF TH MESH SINCE WE ARE USING THE ACADEMIC LISENCE OF ANSYS. HERE WE WILL NAME 1 INLET AND 1 OUTLETS USING NAME SELECTION.

STEP 7-NOW OPEN THE SETUP WINDOW AND LOOK FOR THE MESH WHICH WILL LOOK AS BELOW.

STEP 8: APPLY THE GRAVITY IN NEGATIVE Z DIRECTION WITH A VALUE OF -9.81.

STEP 9: ADD LIQUID WATER AS MATERIAL.

STEP 10:GO TO CELL ZONE CONDITION>FLUID>VOLUME_VOLUME_FLUID AND ASSIGN THE VILUME FLUID AS WATER. OTHERWISE THE VOLUME WILL BE AIR ONLY.

STEP 11: TO BE SAFE DELETE THE AIR FROM MATERIAL.

STEP 12: SINCE IT IS A TURBULENT MODEL ADD K EPSILON METHOD AS THE SOLVING EQN AND CHOOSE RNG FORMAT WITH NEAR WALL TREATMENT AS SCALABLE WALL FUNCTION.

STEP 13: THE BOUNDARY CONDITION WILL HAVE INLET AS PRESSURE INLET. THE VALUE OF THE PRESSURE INLET WILL BE 10 PASCAL.

STEP 14:ALL OTHER BOUNDARY CONDITIONS WILL REMAIN UNCHANGED.

STEP 15: INITIALIZE THE SOLUTION FROM INLET IN STANDARD MODE.

STEP 16:GO TO SOLUTION>NEW>FLUX REPORT>MASS FLOW RATE>CHOOSE INLET

STEP 17: SELECT REPORT FILE AND REPORT PLOT.

STEP 16: TICK THE OUTPUT PARAMETERS.

STEP 17:GO TO RESULTS>CREATE>PLANE. CREATE PLANE ALONG THE CROSS SECTION OF THE PIPE/GATE VALVE

STEP 18:CHOOSE CONTOUR.PLOT THE VELOCITY CONTOUR.

STEP 19:RUN THE SIMULATION FOR 250 ITERATION. AND CLOSE ANSYS FLUENT.

STEP 20:CLICK ON PARAMERTRS. INPUT THE DESIRED GATE LIFT BELOW THE INITIAL VALUE AND TICK ON RETAIN DATA. AND THEN SELECT SOLVE ALL DATAPOINTS.

STEP 21: IT WILL TAKE SOME TIME. THE SOLUTIONS WILL BE ON YOUR SCREEN AS FOLLOWS.

STEP 22: RIGHT CLICK ON ANY ONE AND SET AS CURRENT TO SEE THE DESIRED LIFT OR RELATED RESULT.

RESULTS: LIFT VISUAL PROOF FOR VARIOUS VALUES

LIFT:10MM

LIFT:20MM

LIFT:30MM

LIFT:40MM

LIFT:51MM

LIFT:60MM

LIFT:70MM

LIFT:81MM

LIFT:90MM

THE RESSIDUALS AND PLOTS ARE SHOWN FOR ONLY 1 INSTANCE i.e 90mm GATE LIFT SINCE IT BECAME TOO MUCH CPU INTENSIVE.

MASS FLOW RATE:

.

VELOCITY VENTOR CONTOUR

VELOCITY CONTOUR:

HERE WE HAVE COMPUTED THE PLOTS AND DATA OF FLOW FACTOR AND FLOW COEFFICIENT IN AN EXCEL SHEET BELOW.

PLOT OF GATE VALVE OPENING TO MASS FLOW RATE.

PLOT AND DATA FOR GATE VALVE OPENING TO FLOW COEFFICIENT

PLOT AND DATA FOR GATE VALVE OPENING TO FLOW FACTOR

RESULT:

1. MASS FLOW RATE INCEREASES WITH GATE LIFT.

2. FLOW COEFFICIENT INCREASES WITH GATE LIFT.