Analysis Of Crossflow Heat Exchanger Research Articles

Nano fluids effect on crossflow heat exchanger characteristics – Review

Abstract The main objective of moderation in the heat transfer equipment is to utilize the vitality and capital cost. The Cooling system's thermal performance is mainly based on the Performance of the heat exchanger. The cross-flow heat exchanger works more efficiently with a high rate of heat transfer when compared with shell and tube heat exchanger, spiral heat exchanger, and plate type heat exchanger. One method of enhancement of heat transfer rate in different types of heat exchangers is possible with the use of nano fluids instead of plain fluids. In extent, the study focuses on the specialist's improvement in experimental and analysis of cross-flow heat exchanger which incorporates structure, experimental outcomes with different fluids like air, water, Nano fluids and further more numerical analysis (CFD, COMSOL and ANN). Various investigations have revealed enhancements in heat transfer by a heat exchanger by means of the utilization of nanofluids acquired by suspending X2O3 type oxides, for example, Al2O3, TiO2 and SiO2 in water. Cross flow heat exchanger mostly used for hygienic standards at large canteens, hospitals, food industries and they will not exchange humidity like a rotary heat exchanger.

Coordination analysis of cross-flow heat exchanger under high variations in thermodynamic properties

Supercritical pressure CO2 was employed to investigate the improvement of a cross-flow heat exchanger with variable properties in the present work. The whole heat exchanger was uniformly divided into M×N heat exchange units, and the matrix analysis indicated that the total heat load of the heat exchange matrix depends not only on the vector norms of local heat transfer coefficient and local temperature difference, but also on their distributed coordination. A numerical example confirmed that the total heat load increased as the coordinative degree between the two vectors of local heat transfer coefficient and local temperature difference improved when the other conditions remained unchanged. The further analysis indicated that the coordination improvement between the two vectors of local heat flux density and local heat transfer area also increased the total heat load. A coordination angle was proposed to measure the coordination degree between the distributions of different parameters in heat exchange matrix; the smaller coordination angle means the better distributed coordination when the other conditions remain the same. The present work might provide a new approach to the improvement of heat exchange matrix for the fluids with drastic changes of properties.

Entropy generation minimisation analysis of cross-flow heat exchangers used in indirect evaporative air conditioners

In this paper, entropy generation in heat exchangers used in Indirect Evaporative Coolers (IDECs) is studied. First, expressions for the rate of entropy generation in tube-type and plate-type cross-flow heat exchangers used as IDECs are obtained. Then, by introducing appropriate geometric constraints and employing thermohydraulic design equations, the variation of the rate of entropy generation within the heat exchangers is investigated. The maximum EER, outlet temperatures and the optimum sizes are obtained for several cases. The results of several experiments conducted on an optimum tube-type experimental prototype are presented and compared with the numerical data.

Second law analysis of crossflow heat exchanger in the presence of axial dispersion in one fluid

Abstract In the present paper second law analysis of crossflow heat exchangers has been carried out in the presence of non-uniformity of flow. This non-uniformity is modeled with the help of axial dispersion model and takes into account the back mixing and flow maldistribution. An analytical model for exergy destruction has been evaluated for the cross-flow configuration. A wide range of study of the operating parameters and non-uniform flow on exergetic behavior of crossflow heat exchangers has been carried out. The results clearly bring out not only the reason behind the maximum entropy paradox in heat exchangers but also the proper perspective of exergy destruction and the consequent optimization of crossflow heat exchangers from the second law viewpoint.

Two Functions Used in the Analysis of Crossflow Exchangers, Regenerators, and Related Equipment

Two families of functions, which will be designated as G{sub n}(x,y) and F{sub n}(x,y), find use in the analysis of crossflow heat exchangers, regenerators, packed beds, the transient response of heat exchangers, and related problems. Larsen gives four place tables for G{sub {minus}1}, G{sub 0}, G{sub 1}, F{sub 0}, and F{sub 1} (X,y) (x and y; 0, (1), 20). However, in many applications the values of the functions are required for larger values of the index n, larger values of x and y, and for both arguments negative. The dual purpose of this note is to summarize some properties of the functions and to indicate a rapid method of finding their numerical values.

Approximate Dynamic Analysis of Crossflow Heat Exchanger by the Method of Weighted Residuals

In this paper approximate lumped parameter models by the method of Weighted Residuals (MWR) are given for a cross flow heat exchanger and compared favourably with the Finite Difference Method (FDM). Two kinds of weighting function (Collocation Method). Several numerical examples show that the FDM model must be a considerablly higher order to secure the same accuracy as the MWR model does to simulate the static and dynamic characteristics.