1. The anatomy of the counter-current heat exchanger of skipjack tuna is described and the pattern of blood flow is analysed. 2. The pattern of blood flow is from the dorsal aorta, through the exchanger to segmental arteries to the tissues, from the tissues to segmental veins and back through the exchanger to the post-cardinal vein. 3. The vessels in the exchanger are about the same size as sys...

The increasing heat generation rates in VLSI circuits motivate research on compact cooling technologies with low thermal resistance. This paper develops a closed-loop two-phase microchannel cooling system using electroosmotic pumping for the working fluid. The design, fabrication, and open-loop performance of the heat exchanger and pump are summarized. The silicon heat exchanger, which attaches...

The paper discusses optimal operation of a general heat exchanger network with given structure, heat exchanger areas and stream data including predefined disturbances. A formulation of the steady state optimization problem is developed, which is easily adapted to any heat exchanger network. Using this model periodically for optimization, the operating conditions that minimize utility cost are f...

The objective of this paper is to evaluate and optimize the performance of 1 kW integrated heat exchanger module for new generations of air cooled heat exchangers. The first objective is to minimize the ratio of the header frontal area to the entire heat exchanger frontal which will help to reduce the header size. The second objective is to minimize the pressure drop for the entire heat exchang...

In industrial environments, the heat exchanger is a necessary component to any strategy of energy conversion. Much of thermal energy used in industrial processes passes at least one times by a heat exchanger, and methods systems recovering thermal energy. This survey paper tries to presents in a systemic way an sample control of a heat exchanger by comparison between three controllers LQR (line...

one way to increase the heat transfer is to use perforated twisted tapes with different hole diameters, which largely improve heat transfer with an increase in the heat transfer area at the constant volume and more mixed flow. in the previous studies, the effect of nanofluids with perforated twisted tapes is less studied. in this work, the performance of water / iron oxide nanofluid in a double...

This paper presents the performance of a water-to-refrigerant type ground source multi-heat pump (GSHP) system installed in a school building in Korea. The evaluation of the performance has been conducted under the actual operating conditions of the GSHP system. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 ...

In the present study, the main objective is to evolve a correlation to predict liquid-liquid two-phase heat transfer coefficients in a spiral plate heat exchanger. Experimental studies were conducted in a spiral plate heat exchanger using the liquid-liquid two-phase system of water-diesel in different volume fractions and flow rates as the cold fluid. Experiments were conducted by varying the v...

The paper presents an approach for robust PI controller design for a system affected by parametric uncertainty. The method is based on plotting the stability boundary locus in the plane of controller parameters that is called (kp, ki)-plane. Designed robust PI controller is implemented for control of two counter-current tubular heat exchangers in series with uncertain parameters, in which keros...

Heat exchangers are widely used in heating, air conditioning, refrigeration, industrial plants and refineries, gas processing and water treatment. Fouling is a chronic operating and design problem for retaining highly effective heat exchangers. This leads to countless chemical and mechanical attempts for reducing fouling. Mitigation of fouling and removal of deposits can be addressed efficientl...