Transient Heat Transfer for Forced Convection Flow of Helium Gas Over a Horizontal Plate

Abstract

Transient heat transfer coefficients for helium gas flowing over a horizontal plate (ribbon) were measured under wide experimental conditions. The platinum plate with a thickness of 0.1 mm was used as test heater and heated by electric current. The heat generation rate was exponentially increased with a function of Q 0 exp(t/τ). The gas flow velocities ranged from 4 to 10 m/s, the gas temperatures ranged from 290 to 353 K, and the periods of heat generation rate, τ, ranged from 50 ms to 17 s. The surface superheat and heat flux increase exponentially as the heat generation rate increases with the exponential function. It was clarified that the heat transfer coefficient approaches the quasi-steady-state one for the period τ longer than about 1 s, and it becomes higher for the period shorter than around 1 s. Empirical correlation for transient heat transfer was also obtained based on the experimental data.

Experimental and numerical study on transient heat transfer for helium gas flowing over a flat plate containing an exponentially increasing heat source

“…The uncertainties of the measurement of the heat generation rate, the heat flux of the test heater, and the heater surface temperature are estimated to be ±1%, ±2%, and ±1 K, respectively (Liu, et al 2008a). And the uncertainty for the obtained heat transfer coefficient is estimated to be ±2.5%.…”

“…Experimental apparatus was reported in previous works (Liu, et al 2006(Liu, et al , 2008a(Liu, et al , 2008b. The experiment apparatus is composed of gas compressor, flow meter, test section, surge tank, cooler, the heat input control system, and the data measurement and processing system.…”

“…They are less than about 5.1% of the measured heat flux. On the other hand, the radiation contribution was also estimated to be less than 0.27% of the measured heat flux (Liu, et al 2008a). Based on the estimations, the natural convection and radiation effects are small and can be neglected in this research.…”

“…However, when it comes to transient state, the calculated RPV (Reactor Pressure Vessel) temperature and lower permanent reflector block temperature have large differences from measured ones. Liu and Fukuda (2002), Liu, et al, (2008aLiu, et al, ( , 2008b obtained the experimental data and correlations for parallel flow of helium gas over a horizontal cylinder and a plate. They investigated the diameter-effect of cylinders and the geometric effect of heaters on transient heat transfer.…”

Experimental and numerical study of transient heat transfer for forced convection flow of helium gas over a twisted plate

“…The numerical solution is considered as one of the approach for heat transfer enhancement. In our previous research, Liu et al (2006Liu et al ( , 2008Liu et al ( , and 2014 obtained the experimental data and correlations for parallel flow of helium gas over a horizontal cylinder and a plate. The diameter and geometric effect of heaters on transient heat transfer were investigated under wide experimental conditions.…”