| b | stoichiometry of deposit material |
| Ca | gas phase concentration, mol/m3 |
| Ca0 | initial gas phase concentration, mol/m3 |
| Cb | solid phase concentration, mol/m2 |
| Cb0 | initial solid phase concentration, mol/m2 |
| Cb0max | peak initial solid phase concentration, mol/m2 |
| Cpg | gas phase heat capacity, J/mol・K |
| Cps | solid phase heat capacity, J/mol・K |
| De | dispersion coefficient, m2/s |
| d | diameter of the exhaust pipe |
| E | activation energy, J/mol |
| h0 | heat transfer coefficient in the pipe, J/s・m2・K |
| ha | outside heat transfer coefficient from pipe to ambient, J/s・m2・K |
| ΔH | heat of reaction, J/mol |
| k | reaction rate coefficient, m3/mol・s |
| k0 | pre-exponential factor, m3/mol・s |
| L | length of exhaust pipe, m |
| m | 1/4 of the pipeline length, m |
| r | radius of exhaust pipe, m |
| Qd | heat dissipation, J/m3 |
| Qa | heat accumulation, J/m3 |
| R | ideal gas constant, J/mol∙K |
| t | time, sec |
| Ts | solid phase temperature, K |
| Ts0 | initial solid temperature, K |
| Tg | gas phase temperature, K |
| Tg0 | initial gas phase temperature, K |
| Ta | ambient temperature, K |
| u0 | gas velocity, m/s |
| z | distance along the pipe, m |
| ρs | density of solid phase, mol/m3 |
| ρg | density of gas phase, mol/m3 |
| λe | thermal conductivity of the gas phase, W/mol∙K |