Simulation analysis of heat transfer and flow characteristics of a U-tube heat exchanger in a molten salt reactor

Fig. 2. Meshing diagram of overall (a), cross section of the solid domain (b) and cross section of the fluid domain in bending area (c) of MSRE-PHX

Fig. 3. Simulation results of bulk temperature (a), pressure drop (b), cumulative duty (c), Re (d) and heat transfer coefficient (e) of HTRI

Fig. 4. The cloud map of temperature distribution (a) and flow paths colored with temperature (b) of MSRE-PHX

Fig. 5. The cloud map of pressure distribution (a) and flow paths colored with pressure (b) of MSRE-PHX

Fig. 6. The cloud map of velocity distribution (a) and flow paths colored with velocity (b) of MSRE-PHX

Fig. 7. Velocity vector diagram at the shell side of MSRE-PHX

Table 1. Structural parameters of MSRE-PHX

Table 1. Structural parameters of MSRE-PHX

参数Parameter	值Value
折流板间距Baffle spacing / mm	304.8
折流板厚度Baffle thickness / mm	6.4
总壳长Overall shell length / m	2.438 4
壳侧内径Inner diameter of shell / mm	406.4
平均管长Average tube length / m	4.267 2
管数Tube number	159
管道间距Tube pitch / mm	19.685
管道外径Outer diameter of tube / mm	12.7
管道厚度Tube thickness / mm	1.067
有效换热面积Effective heat transfer surface / m²	25.9
管板厚度Tube sheet thickness / mm	38.1

Table 2. Operating parameters of the MSRE-PHX

Table 2. Operating parameters of the MSRE-PHX

参数Parameter	壳侧Shell side	管侧Tube side	来源Source
入口温度 Inlet temperature ^a / ℃	662.78	551.67	ORNL-TM-2098^[25]，1968
出口温度Outlet temperature ^a / ℃	635	593.33	ORNL-TM-2098，1968
质量流量Mass flow ^{b, c} / kg·s^-1	171.24	105.75	ORNL-TM-2098，1968
压降Pressure drop ^c / kPa	165.5	199.9	ORNL-TM-2098，1968
单侧换热系数Heat transfer coefficient of each side ^c / W∙m^-2∙K^-1	8 499.9	11 293.46	ORNL-TM-3039^[26]，1973
总换热系数Overall heat transfer coefficient ^c / W∙m^-2∙K^-1	3 724.74		ORNL-TM-3039，1973

Table 3. Thermal properties of molten salts in MSRE-PHX

Table 3. Thermal properties of molten salts in MSRE-PHX

热物性 Thermal property	燃料盐原始值 Original values of fuel salt	冷却盐原始值 Original values of coolant salt	燃料盐修正值 Corrected values of fuel salt	冷却盐修正值 Corrected values of coolant salt	冷却盐推荐值 Recommended values of coolant salt
热导率 Thermal conductivity / W∙m^-2∙K^-1	4.76	6.06	1.44	1.14	1.1
黏度Viscosity / mPa∙s	7.4	8.27	7.73	9.76	$0.16 e x p (3 755 / T [K])$
密度Density / kg∙m^-1	2 471.66	1 922.22	2 261.81	1 971.88	$2 413 - 0.488 \times T [K]$
比热容Specific capacity / J∙kg^-1∙K^-1	1 924.64	2 384.88	1 981.12	2 414.17	2 386

Table 4. Theoretical verification results of MSRE-PHX

Table 4. Theoretical verification results of MSRE-PHX

参数Parameter	管侧Tube side Gnielinski	壳侧Shell side Kern	管侧Tube side Gnielinski	壳侧Shell side Bell-Delaware
出口温度Outlet temperature / ℃	577.66	643.45	580.91	641.03
压降Pressure drop / kPa	211.82	140.09	211.5	250.26
单侧换热系数Heat transfer coefficient of each side / W∙m^-2∙K^-1	9 742.9	8 901.9	9 808.1	13 771.4
总换热系数Heat transfer coefficient of each side / W∙m^-2∙K^-1	3 506.3		4 087.3
总换热量Total heat transfer rate / MW	6.557 6		7.377 4

Table 5. Comparison of experiment results with theoretical calculation and simulation analysis of MSRE-PHX