Ana Sayfa Genel 17 Haziran 2022

New Goff–Gratch, Hyland–Wexler, and Wagner–Pruss formulas is actually monotonous and inconvenient for usage for the figuring the newest saturation steam tension

New Goff–Gratch, Hyland–Wexler, and Wagner–Pruss formulas is actually monotonous and inconvenient for usage for the figuring the newest saturation steam tension

Koutsoyiannis has just derived an equation getting figuring saturation steam stress from water using the Clausius–Clapeyron picture and you can revealed that the fresh cousin difference on site datasets are brief out-of ?40° to 50°C (Koutsoyiannis 2012)

We have witnessed much research into formulating the newest saturation vapor tension. Bosen gave an algorithm to own calculating this new saturation steam tension from drinking water having realistic accuracy in the heat include ?51.1° in order to 54.4°C (Bosen 1960). Langlois created an effective fractional formula for computing new saturation vapor tension out-of h2o and opposed the outcomes with the seen beliefs for the Byers (1959) plus the formula in the Berry et al. (1945). The fresh new fee mistake compared to the fresh observations try seen to be smaller than 0.5% over the temperature list of 0°–35°C (Langlois 1967). Richards derived a four-training polynomial on the saturation steam tension away from water during the temperature consist of ?50° in order to 140°C (Richards 1971). Tabata advised good quadratic formula you to definitely produced the latest saturation vapor tension which have a hateful commission error from 0.17% into the temperatures are priced between 0° to thirty five°C (Tabata 1973). Lowe offered a 6th-education polynomial algorithm to own calculating the new saturation vapor tension out of h2o out-of ?50° in order to fifty°C and you can examined they up against the Goff’s equation. The results revealed that the precision was high (Lowe 1977). Rasmussen demonstrated a five-studies polynomial and you can a 6th-degree polynomial having calculating the newest saturation steam pressure more than liquid (out of ?50° to help you fifty°C) and over freeze (regarding ?50° so you’re able to 0°C) and another four-degree polynomial to your saturation steam tension more freeze. The maximum cousin error are suprisingly low (Rasmussen 1978). Gueymard made use of a least squares method to obtain about three formulas for the fresh new saturation steam tension more than water and you can compared the computed abilities on new ASHRAE resource data. It had been shown why these about three formulas you will estimate new saturation steam pressure having high accuracy (Gueymard 1993). Sanjari advised a good nonlinear picture to have figuring the fresh new saturation steam stress of 75 absolute substances by using multiple regression investigation, and you will analysis of your own calculated results together with studies from the books indicated that the brand new imply relative deviation involved 0.1% to have h2o (Sanjari 2013). The warmth assortment wasn’t given from inside the Sanjari (2013).

Dollars made use of good minimax fitting processes over the heat variety of really interest in meteorology and you will derived one or two equations to have calculating new saturation vapor tension away from h2o (away from ?20° to help you 50°C) as well as freeze (regarding ?50° to 0°C), correspondingly (Money 1981)

The above mentioned-mentioned formulas will always be state-of-the-art. Particular experts generated certain tries to expose easy equations suited to brand new resource analysis in the form of regression data. Tetens advised several brief formulas, one of that was of Magnus form, to possess measuring the saturation steam stress of liquids and of frost (Tetens 1930). The fresh new vapor stress thinking given by so it formula was indeed appropriate for really meteorological intentions (Murray 1967), although relative mistake available with the latest Tetens formula enhanced with ). In particular, during the temperatures less than ?25°C the new mistakes had been more than step 1% (Murray 1967). Bolton delivered an empirical algorithm on the saturation vapor pressure off water and you will indexed that the mistake try 0.4% along side temperature range from ?35° in order to thirty-five°C (Bolton 1980). Alduchov and Eskridge generated good entry to an enthusiastic iterative processes and you can minimum squares way of improve brand new coefficients of the Magnus formula and you may required a couple of equations to possess calculating brand new saturation vapor pressure more liquids (out of ?40° so you can fifty°C) as well as over frost (of ?80° in order to 0°C), respectively. Those two equations yielded restriction cousin error of below 0.384% and you will 0.213%, correspondingly (Alduchov and you can Eskridge 1996). Leckner determined brand new saturation vapor tension out-of liquid having fun with an easy great function (Leckner 1978). Stephens projected the new saturation vapor pressure out of liquid by using a simple algorithm which had been according to research by the Clausius–Clapeyron picture (Stephens 1990).

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