Experimental study on heat transfer and pressure drop in mercury flow system for spallation neutron source

Figures & data

Figure 1 Schematic diagram of the mercury experimental loop

Table

Flow rate	15 liters/min (2.5 × 10^−4 m^3/s) by electromagnetic pump
	20 liters/min (3.3 × 10^−4 m^3/s) by gear pump
Inventory	Maximum 30 liters
	At testing 20 liters
Material	316 stainless steel
Pressure	Maximum 0.5 MPa
	At testing 0.4 MPa

Figure 2 Schematic drawing of the test section

Figure 3 External view of the test section

Table

Pressure sensor	0.2%
E-M flow meter	0.2%
Thermocouple	For stainless steel pipe temperature 0.1%
	For heater temperature 0.1%
	For mercury temperature 0.7%

Table

Maximum flow rate	0.6 m^3/hr (Electromagnetic pump)
	1.2 m^3/hr (Gear pump)
Maximum velocity in the test section	about 2 m/s
Pressure	0.4 MPa
Inlet temperature	up to 40°C (313K)

Figure 4 Relationship between pressure drop and mercury velocity

Figure 5 Relationship between friction factor and Reynolds number

Figure 6 Roughness Reynolds number of mercury (roughness k = 35 and 85 μm)

Figure 7 Relationship between heat transfer coefficient and mercury velocity

Figure 8 Experimental data and correlations expressed as relationship between Nusselt number and Peclet number

Figure 9 Analytical model for heat transfer analysis

Table 1 y+ value for Reynolds number

Reynolds number (Re)	Y ^+	Velocity (m/s)
1.3315E+04	25.001	0.11
3.3287E+04	29.586	0.27
6.6573E+04	30.004	0.54
1.3315E+05	30.509	1.09
2.6502E+05	30.017	2.17
6.6573E+05	32.167	5.45
1.3315E+06	33.106	10.89

Table

Velocity	0.1–10 m/s
Heat flux	99.663 kW/m^2
Wall boundary	No slip condition
Turbulent model	Standard k—ɛ model
Turbulent Prandtl number	1.5

Table

Heat conductivity	8.58 W/m·K
Specific heat	139.2 J/kg·K
Density	13,521.3 kg/m^3
Viscosity	0.001407 kg/m·s

Figure 10 Comparison with experimental and analytical results of friction factor

Figure 11 Comparison with experimental data, analytical results and correlations expressed as relationship between Nusselt number and Peclet number

Figure 12 Temperature distribution of the 3-D analysis

Figure 13 Heat transfer coefficient distribution of the 3-D analysis

Figure 14 Heat transfer coefficient along with flow direction