The continued high cost of energy has mandated that the Chemical Process Industries reduce operational and capital costs through process heat integration. However, the heat integration of process streams can lead to process structures that are difficult to operate and control. This paper addresses the control of heat exchanger networks and it shows the importance of dynamic simulations in the s...

This paper investigates the robustness of a time delayed system controlled by a PI controller with a Smith Predictor used to compensate the dead time. A heat exchanger process is used as a test bed for the proposed control structure. Feed-forward control is used to compensate for the disturbance effect. The effectiveness of the design procedure is tested using Matlab-Simulink models and frequen...

the objective of the present study is the synthesis of mwcnt-tio2 hybrid nanostructures by solvothermal synthesis method with ticl4 as precursor. the heat transfer enhancement due to the use of mwcnt-tio2 nanofluid was investigated. as-prepared hybrid materials were characterized by x-ray diffraction (xrd) and scanning electron microscopy (sem). the results showed that mwcnts were uniformly dec...

force convection heat transfer of turbulent nano fluid flow in 90 and 60 degree elbow is simulated by using fluent. single phase model has been implemented to study such a flow field and standard

Previous investigators have concluded that sympathetic activity produces active vasodilatation (4, 6, 8, 10) and active vasoconstriction (6). The possibility that sweat gland activity might cause vasodilatation has also been investigated, but no such relationship has been demonstrated (4). However, it has been reported that indirect’ vasodilatation or vasoconstriction may occur in an extremity ...

We hypothesized that heat stress would decrease anterior and posterior cerebral blood flow (CBF) during exercise, and the reduction in anterior CBF would be partly associated with large increase in extracranial blood flow (BF). Nine subjects performed 40 min of semirecumbent cycling at 60% of the peak oxygen uptake in hot (35°C; Heat) and thermoneutral environments (25°C; Control). We evaluated...

Fouling is a common, fundamental and costly problem in heat transfer systems, which reduces thermal efficiency of equipment, increases the energy loss and causes strong damage to the heat transfer equipment in various industries. The main causes of fouling on the heat transfer surfaces are salts with inverse temperature-solubility in the fluid which calcium sulfate is one of the most important ...

Experiments were conducted to investigate flow boiling heat transfer to a dielectric fluid in a silicon chip-integrated microchannel heat sink. Twenty-four microchannels, each 389 m  389 m in crosssection, were fabricated into the 12.7 mm  12.7 mm silicon substrate. High-speed visualizations (at 12,500 frames per second) were performed simultaneously with heat transfer and pressure drop mea...

cooling towers are widely used in most industrial units to reject waste heat to the atmosphere. this paper deals with an experimental analysis of heat and mass transfer phenomena between water and air by direct contact in a cooling tower. the tower is filled with 6 type packing. in this study temperature and pressure drop and tower characteristics was used in determining experimentally the ther...