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What i learned in week 9? - Coggle Diagram
What i learned in week 9?
Control valve sizing
Valve Coefficient (Cv)
Meaning
Measure of the capacity ot the body and trim of a control valve.
Formular for non-laminar, liquid flow
Calculating
step 2: Check for choked Flow, cavitation and Flashing.
step 3: Determine Specific Gravity.
step 1: Calculate Actual Pressure Drop
step 4: Calculate Approximate Cv.
step 5: Select Approximate Body Size Based on Cv.
Choked Flow
occurs in gas & liquid phase when fluid velocity reaches sonic values.
Flashing
Occurs while pressure fluid lower than vapor pressure until discharge from the valave outlet.
The result is a two phase mixture (liquid & vapor) at valve outlet.
Cavitation
Occurs while pressure fluid lower than vapor pressure.
Occurs bubles collapse.
Nomenclature
Piping Geometry Factor, FP
Expansion Factor, Y
Reynolds Number Factor, FR
Ratio of Specific Heats Factor, Fk
The liquid critical pressure ratio factor, FF
Terminal Pressure Drop Ratio, XT
Measurements System Analysis
Variation
Formular
variace observed = variace product + variace gauge
Types of gage variation
Systematic variation
Periodic variation
Random variation
Main sources of variation (4M+1E)
Machines
Man (People)
Methods
Environment
Materials
Components
Operator and operating instructions
Equipment or gage
Types of gage
Attribute
Variable
Measurement error
Meaning
Difference between a value measured and the true value.
Components
Accuracy (bias)
Linearity
Resolution
Stability (consistency)
Precision –Repeatability & Reproducibility
Improve gage capability
Reproducibility
Repeatability
TemperatureMeasurement
Thermowell
For a contact temperature measurement device.
Thermal expansion techniques
Bimetallic thermometers
Constructed by bonding two straight metal strips.
The metal with the largest coefficient of expansion is on the bottom.
Liquid-in-glass Thermometer
Total-immersion Thermometers
Partial-immersion Thermometers
Electrical Techniques
Thermocouples
(to be continue to next week)
