Calculation of the mass transfer coefficient typically requires an empirical correlation and is where the molecular weight, wind speed, and temperature dependence comes in. Where $k$ is the mass transfer coefficient, $A$ is the surface area of the spill, and $P^*$ is the vapor pressure. They seem to be based on basic theories defining the evaporation rate as: Unfortunately, I don't know enough about the equations to gauge their accuracy or expected error. Note that your berm and non-berm equations are essentially the same, just with careful calculations of the surface area. Search for the title for a freely available version. Somebody took the time to scan it and has it posted on the internet:Įstimating Rates of Spreading and Evaporation of Volatile Liquids The modified form I found in a paper by John Barry in CEP magazine. The evaporation formula you have is a modification of the EPA method for calculating the evaporation rate. Another example is here where equation #7 is the formula it says to use for spills but I have no idea how it works. I'm willing to do some research but I still have yet to find an acceptable formula/equation I can implement in this program. The closest thing I can find to an equation I can use is from here, but I am unable to decipher the characteristics it is asking since it is extremely technical in that field. This project has nothing to do with school though. I am not an engineer, I am a computer science/mathematics major. I am asking precisely this: are these formulas suitable to use as an approximation for evaporation? If not, what would be a better formula? I am always skeptical about using other people's work without documentation making sure they have proof to backup their claims that this stuff will work. These formulas are not found in any workbook, website, etc. Chemical Sciences index Chemical thermodynamics index: The ideal gas law states the PVnRT, where Ppressure, Vvolume, nnumber of moles of gas, Rthe gas constant, and T.
I don't trust the formulas given, because they were given by another student assigned to this task. Chemical thermodynamics online calculation: Ideal gas law - Find an unknown in the ideal gas law. Pressure index is calculated by class and capacity of compression unit. Here are some of them: General Evaporation Rate Formula From Asphalt Selection of compressors shall rest upon general principles of thermodynamics applied to gas compression theory, comparison of several compressor types, calculation and selection theory and compressor calculation formula to visualize the calculation theory. We do have a number of different areas that have secondary containment, which is referred to as a "Berm", so that is the reason we have two formulas below. Some spills will go directly onto asphalt/gravel or soil.
We have a number of different spills at this location. Molecular weight is pulled from the chemical itself, same with vapor pressure. These are formulas, that are supposed to approximate evaporation, are for a number of different chemicals. I was given formulas for general evaporation, for a spill calculator I am building.