The Pd/ n H system: Transport processes and development of thermal instabilities

Abstract

Recent years have witnessed renewed interest in the hydrogen economy, with emphasis on the metal/hydrogen system and its application to energy conversion efforts. Two industrially important aspects are emphasized, viz. the amount of hydrogen stored and the rate at which it can be transferred (absorbed/desorbed) because they are crucial factors in the design and construction of electrochemical energy conversion devices. The March 1989 announcement of excess enthalpy generation [1], the Fleischmann-Pons effect, provided an added incentive to examine in greater detail the behavior of the Pd/D system at very high electrode loadings and at high cell currents.In an earlier modeling of transport processes, we adopted a multilayer concept of the interphase, formulated transport equations based on the conservation of charge and matter and analyzed events occurring in proximity to the electrode/solution contact surface as a function of the cell current for a set of rate constants characterizing the hydrogen evolution reaction [2]. This model is employed here in the analysis of thermal events associated with the Pd + D codeposition. -Thermal events during Pd + D codepositionThermal events occurring during the electrochemical compression of the Pd/D system are usually discussed in terms of excess enthalpy produced over a period of time, often several days. Thus, they represent an average value and provide no information on the distribution of heat sources. However, when the surface of the electrode producing excess enthalpy is viewed with an infra-red camera, the presence of randomly distributed (in time and space) heat sources of short duration is revealed which subsequently merge to form larger oscillating islands. An example of hot spots recorded in the early stages of Summary. -Surface temperature distribution associated with excess enthalpy production during the codeposition process is presented. The interpretation is sought via the multilayer concept of the electrode/electrolyte interphase. The effect of gas evolution on activities within the interphase is considered.PACS 28.90 -Other topics in nuclear engineering and nuclear power studies.

PRECURSORS AND THE FUSION REACTIONS IN POLARIZED Pd/D–D2O SYSTEM: EFFECT OF AN EXTERNAL ELECTRIC FIELD

“…7a -7c. In a separate study [10], we showed that the excess heat is not produced continuously over the entire electrode volume but at isolated In accordance with the concept that one experiment leads to another we noted the following: An analysis of experimental results suggests that events occurring at the contact surface of the interphase region influence the events in the bulk, ie influence the intensity and type of the nuclear events through the interactions between the D + complexes and the Pd lattice assisted by the stress fields at the reaction sites. Consequently, by placing an operating cell in an external electric field one would expect to see effects quite different from those observed in the absence of field.…”

Evidence of nuclear reactions in the Pd lattice

“…A system far from equilibrium tends to promote cluster formation which, in turn, produces hot spots that can be displayed by infra-red (IR) imaging of the electrode surface (Mosier-Boss and Szpak 1999). The presence of "hot spots" indicates that (i) there are regions of specific interactions involving absorbed deuterium and the Pd lattice and (ii) these interactions produce intense heat sources capable of melting palladium.…”

What Conditions Are Required to Initiate the Lenr Effect?

“…4. Heat bursts are observed that must originate near the surface because their observed size is very small [48][49][50]. Very small melted regions are also seen [51].…”