Application Research on Testing Efficiency of Main Drainage Pump in Coal Mine Using Thermodynamic Theories

Table 2

The test data through the ultrasonic flowmeter method.

Number	Item	Unit	The adjustment point of flow
			1	2	3	4	5
()	The flow	m^3/h	449.03	437.19	407.55	388.02	355.15
()	The pump efficiency	%	72.40	74.13	70.64	69.89	68.88