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The operating limits of oscillating heat pipes (OHP) are crucial for the optimal design of cooling systems. In particular, the dryout limit is a key factor in optimizing the functionality of an OHP. As shown in previous studies, experimental approaches to determine the dryout limit lead to contradictory results. This work proposes a compact theory to predict a dryout threshold that unifies the experimental and analytical data. The theory is based on the influence of vapor quality on the flow pattern. When the vapor quality exceeds a certain limit (x = 0.006), the flow pattern changes from slug flow to annular flow and the heat transfer decreases abruptly. The results indicate a uniform threshold value, which has been validated experimentally and by the literature. With that approach, it becomes possible to design an OHP with an optimized filling ratio and, hence, substantially improve its cooling abilities.

Electromagnetically driven heavy oil recovery is considered as an alternative or as a complementary technique to steam injection methods. Inductive electromagnetic heating (IH) of heavy oil reservoir represents a complicated multi-physics process affected by operating conditions, reservoir and fluid properties. The IH takes place at frequencies of 10-3 - 1 MHz and the principle is based on the eddy currents generation in the mineralized connate water and its Joule heating. This work presents a numerical simulation study of IH assisted heavy oil recovery. Previously developed coupled electromagnetic and reservoir simulation workflow is applied for this analysis. The workflow incorporates coupling between ANSYS Emag and CMG STARS. The study is focused on the recovery drive mechanism and influence of the reservoir and operating parameters on the production. The IH is realized via closed inductor loop through which alternating current is passed. In our current study we consider two-dimensional pay zone completely surrounded by impermeable barriers and two horizontal "SAGD – like" well pairs, a pair of producer (lower well) and inductor (upper one). Different well constraint cases and the sensitivity to fluid and reservoir properties (pay zone thickness, depth of a reservoir, distance between wells and electrical conductivity contrast between pay zone and under-, overburden) are evaluated. Operating pressure plays a significant role for the production. It defines the water boiling temperature and controls underground steam generation and consequently the drive mechanism. The sensitivity to fluid and reservoir properties is estimated in terms of production efficiency and recovery factor. Previous works on this topic did not consider particularly IH in much detail. The results obtained in this work provide a comprehensive understanding on IH assisted heavy oil or bitumen production process, drive mechanism behind it and the ways of improvement of this technology.