Table 1. Uncertainties of the Temperature Measurement Values at Different Measuring Points on the Inner Surfaces of the Wall.

	distance between the adjacent tubes of 20 mm				distance between the adjacent tubes of 40 mm				distance between the adjacent tubes of 60 mm				without tube
	point 1	point 2	point 3	point 4	point 1	point 2	point 3	point 4	point 1	point 2	point 3	point 4	point 1	point 2	point 3	point 4
N̅	28.53	28.91	28.94	28.52	28.97	28.92	28.65	28.89	29.21	28.34	28.30	28.76	29.01	28.45	29.41	29.09
σ	0.14	0.12	0.11	0.15	0.14	0.13	0.17	0.14	0.10	0.16	0.16	0.12	0.15	0.18	0.13	0.18
UA	0.012	0.010	0.010	0.012	0.012	0.011	0.014	0.012	0.008	0.014	0.013	0.010	0.012	0.015	0.011	0.015