SI unit

The Shah 1982 CHART correlation for saturated boiling heat transfer as SysML Activity Diagrams (2): Detailed view of the hex$SI$Shah$twophase$htc$combined SI Real convention function variant

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[TECHNICAL SLIDE TRAIL] The Webel libraries for Wolfram Mathematica: With SysMLv1 models.

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SECTION: Miscellaneous examples of applications of Webel libraries for Mathematica to air conditioners and heat exchangers. With SysMLv1 models.

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SysML Activity Diagram

Webel: SysML4Mathematica: Cameo Systems Modeler: Can perform calculations with a custom Quantity ValueType (for Mathematica) directly, but DOES NOT perform units-aware algebra (no automatic conversions)

Webel: Psy/MPsy: Psychrometrics for Mathematica: Due to Mathematica's units-aware Quantity algebra system it is irrelevant what units are used for the input Quantities for creation of the MPsy objects, as long as they are dimensionally consistent!

Example 11: Total (qDotTot), sensible (qDotSen), and latent cooling (qDotLat) required for cooling air

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 10: Condition and dehumidify air by chilling and condensing some moisture: Process table

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 09: Moisture added to air: Amount (mass)

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 08b: Humidification: As a 2-step (3-state) process

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 08a: Humidification: Drying lumber with air: required volumetric air flow rate

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 07: Sensible cooling: 'qDotSen' (-ve): energy transfer rate FROM humid air

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 06: Sensible heating: 'qSen' per mass (+ve): energy transfer TO humid air

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 05: Sensible heating: 'qSen' (+ve): energy transfer TO humid air

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 04: Values from dry bulb temperature 'tdb' and wet bulb temperature 'twb'

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 03b: Values from dry bulb temperature 'tdb' and wet bulb temperature 'twb'

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 03a: Values from dry bulb temperature 'tdb' and wet bulb temperature 'twb'

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 02: Values from dry bulb temperature 'tdb' and wet bulb temperature 'twb' (sling psychrometer)

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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Example 01: Values from 'tdb' and relative humidity 'r'

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TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

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GOTCHA: Mathematica: Specific enthalpy conversion J/kg to Btu/lb: Does not consider a possible "total" enthalpy reference offset vs 0 °C or 0 °F respectively

Mathematica: The Webel Units` package has Quantity variables for frequently used units using a naming convention 'unit$[Symbol]' or 'unit[DescriptiveName]' or unit[Acronym], each with a corresponding '$unit...' for the units identifier String(s).

Mathematica: Use of UnitConvert (or even just multiplication or division by a unit Quantity) MASSIVELY slows the calculations down!

Mathematica: Compile won't work with a Quantity with units

Mathematica: The awesome Quantity system for values with units is everything the SysMLv1.x Quantity/Unit system should have been (and hopefully SysMLv2 will be). But it comes at a high performance cost!

In many English-speaking countries, however, the most common shape of a handwritten Arabic digit 1 is just a vertical stroke; that is, it lacks the upstroke added in many other cultures.

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Webel vs SysPhS-1.1: Annex A.5: Humidifier: Where ValueTypes involving litre are defined, the Unit symbol "L" is used rather than the Modelica-preferred "l" (in combination with an explicit additional unit converter).

In 1990, the International Committee for Weights and Measures stated that it was too early to choose a single symbol for the litre.

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In the UK and Ireland, as well as the rest of Europe, lowercase l is used with prefixes, though whole litres are often written in full (so, "750 ml" on a wine bottle, but often "1 litre" on a juice carton).

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In these countries, the symbol L is also used with prefixes, as in mL and μL, instead of the traditional ml and μl used in Europe.

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The United States National Institute of Standards and Technology now recommends the use of the uppercase letter L, a practice that is also widely followed in Canada and Australia.

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Therefore, the digit "1" may easily be confused with the letter "l". In some computer typefaces, the two characters are barely distinguishable. As a result, L (uppercase letter L) was adopted by the CIPM as an alternative symbol for litre in 1979.

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Originally, the only symbol for the litre was l (lowercase letter L), following the SI convention that only those unit symbols that abbreviate the name of a person start with a capital letter.

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Webel vs SysPhS-1.1: Annex A.5: Humidifier: Where custom ValueTypes are defined, Modelica-friendly Unit symbols are used. Examples: "m3" not "m^3"; "degC" not "°C"; "J/(K.L)" (full stop as multiplier) not "J/(K⋅L)"; (EXCEPT "L" for litre not "l").

Webel vs SysPhS-1.1: Annex A.5: Humidifier: Dimensional analysis of VaporPressureCalculationConstraint implies each 1 mL of water is equated with EXACTLY 1 g of produced vapor.

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