Experimental investigation on flow and heat transfer characteristics of single-phase flow with simulated neutronic feedback in narrow rectangular channel

Single phase forced convection flow and heat transfer of deionized water in horizontal and vertical narrow rectangular channel with gap size of 1.8 mm were experimentally investigated. The integration of thermal hydraulic hardware tests with simulated neutronic feedback has been carried out in this experiment. The results indicated that the transition Reynolds number from laminar to turbulent region in the narrow rectangular channel was about 1500–2300. Compared with the conventional channels, the friction factor became larger in narrow rectangular channel. Nusselt number in narrow rectangular channel was higher than that in conventional channels in laminar region while it was lower in turbulent region. Furthermore, the variations of power, heating surface temperature, inlet/outlet temperature, Re number and Nu number in transient process were investigated with the consideration of neutronic feedback. It indicated that both the quantity and rate of introduced reactivity affected the peak of power. The quantity of power raise was not directly proportional to the introduced reactivity. The delay effect of wall and fluid temperature to the power raise could not be ignored. The temperature peak came later than the power peak. The variations of Re and Nu number were considerable due to the appreciable power raise. In addition, there was no significant difference on the variations of friction factor and Nu number versus Re number between transient and steady state.