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DESIGN AND CONSTRUCTION OF AN INDUCTION FURNACE (COOLING SYSTEM). Presented by MG THANT ZIN WIN Roll No: Ph.D-M-7. Participants: Mg Thant Zin Win (Mechanical) Mg Lin Naing Tun (EC) Ma Cho Cho Ei (EC). Supervisors: Dr Mi Sandar Mon Daw Khin War Oo.
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DESIGN AND CONSTRUCTION OF AN INDUCTION FURNACE (COOLING SYSTEM) Presented by MG THANT ZIN WIN Roll No: Ph.D-M-7 Participants: Mg Thant Zin Win (Mechanical) Mg Lin Naing Tun (EC) Ma Cho Cho Ei (EC) Supervisors: Dr Mi Sandar Mon Daw Khin War Oo 4th Integrated Seminar 4.5.2005
Determining the Tower Capability • Characteristic Curve Method It can be performed using the Demand Curve tab, along with appropriate data supplied by the manufacturer and field test data. • Performance Curve Method It can be performed using the Mechanical Draft Performance Curve tab, along with a set of performance curves supplied by the tower manufacturer or rebuilder and field test data.
Cooling Tower Demand Curves • It is the numerical solution of the Merkel integral over the wide range of L/G values. • Use in designing cooling towers. • Apply for analysis of test data. • Evaluate for the prediction of cooling tower performance. • Plot with the thermal demand, KaV/L, and L/G. • Contain the values of KaV/L, cooling ranges and approaches
Limitations on use of Demand Curve Actual tower performance may deviate from predicted at water loading and air velocities. The followings affect it. • At very low water loadings • At very high water loadings • At very high air velocities • Changing the airflow due to air-side resistance
Cooling Tower Characteristic Curves • To analyze the thermal performance capability of a specified cooling tower. This equation is used for each demand curve. where, KaV/L = Tower characteristic, C = Constant related to the cooling tower design, L/G = Liquid and Gas ratio, and m or slope = Exponent related to the cooling tower design
Illustration of Tower Demand Curve, Characteristic Curve and Design Point Fig (1) – Tower Curve Descriptions
Constructing the Demand and Characteristic Curves Use the following data. • Wet bulb temperature = 75°F • Hot water temperature (T1) = 100°F • Cold water temperature (T2) = 80°F • Temperature range = 20°F • Approach = 5°F • L/G ratio = 0.8662 Needs. • To construct the demand and characteristic curves of a specified cooling tower • To plot the performance curve.
Creating the Demand Curve with CTI Toolkit v3.0 Software Procedures • Enter the values of wet bulb temperature, range and altitude. • Put in the fill or tower coefficients C and slope (m). • Define the design point. • Click on “Recalculate” brings up the appropriate group of demand curves. DEMONSTRATE THE SOLVING PROCEDURES IN OTHER WINDOW DIALOG BOX DETAILEDLY.
L/G Line Design Point Characteristic Curve KaV/L Line DemandCurve The Complete Work Sheet Dialog Box
Constructing the Performance Curve of the Cooling Tower by using CTI Toolkit v3.0 Software Steps • Recalculate the approach temperature by changing the WBT again and again. • Record each approach temperature. • Then, calculate the CWT corresponding to the WBT and approach. • Plot CWT versus WBT.
Plotting the Tower Performance Curve Fig (2) – Off-Design Performance Curve
Conclusion • The performance curves are used to determine the cooling tower capability. • Tower demand curves are a graphical worksheet that facilities cooling tower calculations. • A set of performance curves of the standardized cooling towers is supplied by the tower manufacturers and companies. • Generally, it is experimentally determined by measuring field test data.