Robert E. Holtz

On the role of inert gas in incipient boiling liquid metal experiments

Abstract In experimental studies which measure the amount of liquid superheat required to nucleate the liquid alkali metals, a considerable amount of conflicting and for the most part, unexplained data have been presented. The incipient superheat has been shown or postulated to be affected by the pressuretemperature history, liquid velocity, pressure, heat-flux, liquid purity, dissolved gas content, surface conditions, particle radiation, heating method, length of a time of operation, and perhaps others. This paper presents a theoretical study of the effect of inert gas on incipient superheats and illustrates that among other things, the gas diffusion from surface cavities into the liquid solution accounts for the so-called “heat-flux effect”. On the basis of this study, it was determined that almost all of the published data do not include sufficient information to adequately characterize the experimental systems. The non-specification of the inert gas partial pressure in the gas cover blanket, for example, can cause an uncertainty in the incipient superheats as large as 100°C.

The Vaporization of Superheated Sodium in a Vertical Channel

Measurements of the vapor growth patterns and rates following the nucleation of superheated sodium in a vertical rectangular channel are presented and discussed. The vapor was found to grow as a single bubble for incipient bulk-liquid superheats greater than about 10 deg C, and this single bubble tended to completely fill the channel cross section (except for a thin liquid film on the walls) and to grow as a vapor slug for incipient bulk-liquid superheats greater than about 50 deg C. The temperature gradients in the liquid both normal and parallel to the channel axis prior to nucleation were found to have an important effect upon the dynamics of the vapor slug. Experimental data on the vapor growth and collapse rates and the associated pressure transients are presented for boiling pressures up to 1 atm and incipient superheats up to about 180 deg C.

The prediction of incipient boiling superheats in liquid metal cooled reactor systems

Abstract A modeling technique which enables the calculation of the incipient boiling superheats occurring during various postulated LMFBR accidents is presented. This modeling technique is applied to various reactor systems. It is demonstrated that the system geometry plays a key role in determining the incipient boiling superheats in a flowing system.

Testing of a sodium heat pipe

The operation of a heat pipe with both thermal radiation and convection heat rejection has been experimentally examined. The thermal radiation heat rejection conditions are similar to those which would be experienced in a space environment. The experimental results show good agreement with the analytical model.

On the grid connection of an integrated community energy system

Abstract This paper describes the possible modes of operation for a grid connected integrated community energy system. It is seen that this operating mode influences both the design and the operating rules of the system. Also, it is shown that it is essential to examine the overall energy savings to the community, not just the efficiency at which the energy system is operating.