Gunn Yamada method

The Gunn-Yamada method is a method based on the theorem of coincident states for estimating the liquid volume of pure substances as a function of temperature. The method requires the critical temperature T _c , the acentric factor ω and a volume at T _R = 0.6 as input values .

Determining equations

${\displaystyle {\frac {V}{V_{SC}}}=V_{\mathrm {R} }^{(0)}\left(1{,}0-\omega \delta \right)}$

V _R ⁽⁰⁾ and δ are generalized functions that only depend on the critical temperature T _c or the reduced temperature T _R = T / T _c .

For 0.20 < T _R <0.80 the following applies:

${\displaystyle V_{R}^{(0)}=0{,}33593-0{,}33953\,T_{R}+1{,}51941\,{T_{\mathrm {R} }}^{2}-2{,}02512\,{T_{R}}^{3}+1{,}11422\,{T_{R}}^{4}}$

For 0.80 <T _R <1.00 the following applies:

${\displaystyle V_{R}^{(0)}=1{,}0+1{,}3\,(1-T_{R})^{1/2}\ \log _{10}(1-T_{\mathrm {R} })-0{,}50879\,(1-T_{\mathrm {R} })-0{,}91534\,(1-T_{\mathrm {R} })^{2}}$

For 0.20 <T _R <1.00 the following applies:

${\displaystyle \delta =0{,}29607-0{,}09045T_{R}-0{,}04842\,{T_{R}}^{2}}$

V _SC ( scaling volume) can be determined from a known volume at T _R = 0.6:

${\displaystyle V_{\mathrm {SC} }={\frac {V_{0{,}6}}{0{,}3862-0{,}0866\omega }}}$

By rearranging the main determining equation, a volume at any temperature can be used to determine the scaling volume:

${\displaystyle V_{\mathrm {SC} }={\frac {V}{V_{\mathrm {R} }^{(0)}\left(1{,}0-\omega \delta \right)}}}$

With the determined V _SC , V = f ( T ) can then in turn be determined.

quality

The authors give a mean error of 0.5% for non-polar and slightly polar substances with a maximum deviation of 2.2% between experimental and calculated values. Strongly polar components (e.g. methanol and water ) give significantly greater deviations.

literature

1. ^ Gunn Robert D., Yamada Tomoyoshi, "A Corresponding States Correlation of Saturated Liquid Volumes", AIChE J., 17 (6), pp. 1341-1345, 1971