Freezing Method for Rock Cross-Cut Coal Uncovering: Aging Characteristic of Effective Freezing Distance on Injecting Liquid Nitrogen into Coal Seam

Table 2

Model parameters.

Parameters	Symbol	Value	Unit
Coal density (not frozen)	ρ	1430	kg/cm^3
Coal density (frozen)	ρ	1350	kg/cm^3
Specific heat capacity (not frozen)	Cp	1360	kJ/(kg·K)
Specific heat capacity (frozen)	Cp	1180	kJ/(kg·K)
Thermal conductivity	k	AT + B	W/(m·K)
Coal radius	R	0.45	m
Radius of cold source	r0	0.055	m
Coal height	H	0.9	m
Initial temperature	T0	300.3	K