Commit e6f325e3 authored by Lore, Jeremy's avatar Lore, Jeremy
Browse files

Cleanup phys_const and add ideal gas example

parent ca615c04

matlab/bfield_library_jdl/pumping/ideal_gas_law.m

0 → 100644
+117 −0
Original line number Diff line number Diff line 
clearvars;



%% Definitions

% Throughput Q 

% (Torr-Liters/sec) = P (Torr) * S (L/s) 

% (Pa m^3/s)

% also called "standard condition volumetric flow"

%

% 



% 0C = 273.15 K



pc = phys_const;



% Ideal gas law

% p*V = (m/M)*R*T = (N/NA)*R*T = N*k*T

% p = n*k*T

% m = mass

% M = molar mass (kg/mol)

% N = number of particles

% n = density

% NA: 1/mol

% R = NA*k: J/K/mol General gas constant

% kB: J/K



% %%%%%%%%%%%%%%%%%%%%%%%%%%%

% Inputs

% %%%%%%%%%%%%%%%%%%%%%%%%%%%



%% Temperature



    % Define in deg C

%     T_C = 20;

%     T_K = T_C + 273.15;



%     % Define in K

    T_K = 273.15;  % 0C

    T_C = T_K - pc.convert.C_to_K_Add;

    T_eV = T_K*pc.convert.K_to_eV;

    

%     % Define in eV

%     T_eV = 0.025;

%     T_K = T_eV*pc.e/pc.kB





%% Mass



    % Define as molar mass

%     M_gPermol = 2.014;

    M_gPermol = 4.002602;

    M_kgPermol = M_gPermol/1e3;

    m = M_kgPermol/pc.NAvogadro;



%% Pressure



    % Define in Pa

    p_Pa = 1e3*100; 

    p_mTorr = p_Pa*pc.convert.Pa_to_mTorr;



% Molar masses (g/mol)

% D2 = 2.014

% H2 = 2.016

% He = 4.002602

% Water vapor = 18.02

% Neon = 20.179

% N2 = 28.0134

% Air = 28.966

% Ar = 39.948

% CO2 = 44.01



% Radii in A

% H0 - 0.529

% H2 - 1.37   (I've also seen 1.2)

% N2 - 1.75

% He - 1.1





% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Outputs

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

cbar  = sqrt(8*pc.kB*T_K/pi/m);

cprob = sqrt(2*pc.kB*T_K/m);



n = p_Pa*pc.NAvogadro/(pc.Rgas*T_K); % should be the same as p/(kT)

rho = m*n; 



fprintf('For gas with: \n')

fprintf('             Molar mass = %.3f (g/mol), m = %.3e (kg)\n',M_gPermol,m)

fprintf('             T = %.3f (K) = %.3f (C), = %.3e (eV)\n',T_K,T_C,T_eV)

fprintf('             p = %.3f (Pa) = %.3f (mTorr)\n',p_Pa,p_mTorr)

fprintf('  cbar = %.3e (m/s)\n',cbar)

fprintf('  n = %.3e (m^-3), rho = %.3e (kg/m^3)\n',n,rho)





% Given a flow rate of molecular hydrogen, assume the pressure

% is for molecular particles at 273.15 K. Then divide by kT and appropriate 

% pV unit conversion to get particles/s, where particles = molecules. Then if you

% want atoms/s multiply this by 2. So convert Torr-L/s to Pa*m^3/s by dividing by

% 7.5.  Then divide by kT, this gives 1 Torr-L/s = 3.5355e19 molecules per second 

% and 7.07e19 atoms/s, and 11.33 A/s. 





% r_m = 1.37e-10;  % radius 



%

% d_m = 2*r_m;

% 



% p_Pa/(pc.kB*T_K)

% 

% effective_collision_area = pi*d_m^2

% mfp = 1/(sqrt(2)*effective_collision_area*density)





% Veff = (M_kgPermol/pc.NAvogadro)/rho; % Effective volume

% Vatom = (4/3*pi)/8*Veff;  % Ratio of unit sphere to unit cube

% reff = (Vatom/(4*pi/3))^(1/3)
 
 No newline at end of file

matlab/bfield_library_jdl/util/phys_const.m

+8 −2
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ function pc = phys_const(want_name) 
% M_m         = 4.028;

% M_a         = 2.014;



pc.amu  = 1.660539040e-27;     % kg

% pc.amu  = 1.660539040e-27;     % kg

pc.me   = 9.10938215e-31;      % kg

pc.mp   = 1.672621637e-27;     % kg

pc.e    = 1.602176487e-19;     % C
@@ -16,7 +16,13 @@ pc.kB = 1.38064852e-23; % J/K 
pc.convert.Pa_to_mTorr = 7.5;

pc.convert.K_to_eV     = pc.kB/pc.eV;

pc.convert.eV_to_K     = pc.eV/pc.kB;

pc.NAvogadro = 6.0221409e+23;

pc.convert.C_to_K_Add  = 273.15;

pc.convert.L_to_m3 = 1e-3;

pc.convert.m3_to_L = 1e3;

pc.NAvogadro = 6.0221409e+23; % 1/mol

pc.Rgas = pc.NAvogadro*pc.kB;

pc.amu = 1/pc.NAvogadro/1000; % kg





if nargin == 1

    try