{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

index(9)

# index(9) - Formulae Collection Revised Contents 1...

This preview shows pages 1–4. Sign up to view the full content.

Formulae Collection Revised 5/4/04 Contents 1 Introduction 1 2 Units 1 3 Properties 1 4 Formulae for substances 2 4.1 Substances with B-tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4.2 Ideal Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4.2.1 Ideal gasses in A.7.1 or A8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4.2.2 Ideal gasses with constant specific heats . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4.3 Solids and Liquids without B-tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5 Processes 4 5.1 Control Mass Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5.2 Rate Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.3 Steady State Control Volume Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 Cycle Devices 7 1 Introduction These formulae are not guaranteed to be complete and/or correct, though we tried to make them so. The student has the final reponsibility for knowing all formulae covered in both class lectures and homework correctly. So, if you see an error, or miss a formulae that you think was covered, (if you are mistaken about that, it could get you in trouble!), let us know immediately. This document can not be taken to the exams. 2 Units Basic SI units are kilogram (kg), meter (m), and second (s). Many derived units exist (table A.1). The book uses kPa, kJ, kW instead of the “normal” units Pa, J, W. Conversions may be needed (table A.1) Definitions (table A.1): 1 bar = 10 5 Pa. 1 atm = 101,325 Pa. 1

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Absolute temperature (required in most formulae and some tables): add 273.15 to convert Centrigrade into Kelvin, substract 273.15 to convert Kelvin into centrigrade. However, temperature differences are the same in Kelvin as in Centrigrade; the two temperatures in the difference do not need to be converted. 3 Properties The intensive specific properties are lowercase, the corresponding extensive properties are uppercase: v = V m u = U m h = H m s = S m V = mv U = mu H = mh S = ms Definitions of enthalpy and entropy: h u + pv s integraldisplay ref parenleftbigg δq T parenrightbigg rev Specific volume and density: v = 1 ρ Pressure and force: F = pA Static pressure differences versus height H (height also indicated by Z ) differences: p A - p B = - ρg ( H A - H B ) Number of kilomoles: ¯ n = m M where M is the molecular mass (table A.5.) 4 Formulae for substances How you treat a substance depends on the type of substance. 4.1 Substances with B-tables Tables of specific properties such as tables B.1.1-B.1.4 for water are available. Use requires normally drawing pv - and Tv - or Ts -diagrams, which students must master, and which is covered elsewhere 1 . In the two phase region: v = v f + x ( v g - v f ) u = u f + x ( u g - u f ) h = h f + x ( h g - h f ) s = s f + x ( s g - s f ) 1 http://www.eng.fsu.edu/~dommelen/courses/eml3100/aids/tables 2
where f stands for the saturated liquid ( x = 0) value at the same pressure and same temperature, and g for the saturated vapor ( x = 1) value. These can be found in the Appendix B tables. The quality x is the ratio of the vapor mass to the total mass of vapor and liquid. The quality x is undefined if the substance is not two-phase or saturated.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}