Comparative Analysis of CTF and Trace Thermal-Hydraulic Codes Using OECD/NRC PSBT Benchmark Void Distribution Database

Table 1

CTF modeling of the interfacial drag.

Interfacial drag forces	Between continuous liquid and vapor: 𝜏𝐼,vap_liq=𝐾𝐼,vap_liq𝑈vap_liq
	Between entrained liquid and vapor: 𝜏𝐼,vap_ent=𝐾𝐼,vap_ent𝑈vap_ent
Interfacial drag coefficients	Bubbly flows
	For small bubbles:
	𝐾𝐼,vap_liq𝐶=0.375^𝐷bub𝑟bub𝛼vap𝜌liq𝑈vap−𝑈liq; 𝐶𝐷bub=24Rebub1+0.1Re^0.75bub
	For large bubbles:
	𝐾𝐼,vap_liq𝐶=0.375^𝐷Lbub𝑟bub𝛼vap𝜌liq𝑈vap−𝑈liq; 𝐶𝐷Lbub=max24ReLbub1+0.1Re^0.75Lbub𝛼^2liq,0.45𝛼^2liq
	Annular flow
	Between continuous liquid film and vapor core:
	𝐾𝐼,vap_liq𝑓=2^𝐼𝐷hyd𝛼vap+𝛼ent𝜌vap𝑈vap−𝑈liq; interfacial friction factor 𝑓𝐼 by Henstoch and Hanratty
	Between entrained liquid film and vapor core:
	𝐾𝐼,vap_drop𝐶=0.375^𝐷drop𝑟drop𝛼ent𝜌vap𝑈vap−𝑈ent; 𝐶𝐷drop=24Redrop1+0.1Re^0.75drop