The book deals with the numerical simulation of compact heat exchangers that are primarily used in dissipating heat generated by electronic components and assemblies. The forced-convective cooling of a horizontally based pin-fin assembly has been investigated for the pressure drop and heat transfer characteristics. The effect of pin fin’s thermal conductivity on the performance of heat exchanger is investigated by considering different fin materials. Subsequently the computations for different fin spacing along the stream-wise direction were carried out. The thermal and fluid-dynamic characteristics along the computational domain are discussed in detail. Finally the performance characteristics of triangular fin heat exchangers are studied and a comparison was made with circular pin fins. The results showed that circular pin fins perform better than triangular pin fins with less pressure drop. The book should be especially useful for the engineers and researchers working in the field of conjugate heat transfer and compact heat exchangers.
Heat Exchangers find innumerable applications in process, power, petroleum, transport, air conditioning, refrigeration, cryogenics, heat recovery, energy, pharmaceuticals and other industries. Improper heat exchanger design can lead to huge energy losses resulting in a declining overall plant efficiency. This small book provides the basis of thermal,fluid and mechanical design, material selection and manufacturing processes of heat exchangers.
In this book, our objective is to design and optimize Plate and Frame heat exchanger. The plate and frame heat exchanger was originally introduced in the 1930s and is used extensively in the oil industries . Plate and frame heat exchangers consist of several metal sheets with corrugated surfaces that are clamped together .The irreversibility of any heat exchanger is due to two factors; The transfer of heat across the stream-to-stream temperature difference and the frictional pressure drop that accompanies the circulation of fluid through the apparatus. The fluid friction and heat transfer irreversibility can systematically be reduced by showing down the movement of fluid through the heat exchanger. In other words, optimization process is synonymous with employing larger heat exchanger, where there is more heat transfer area and less heat exchanger volume. Hence, after designing a heat exchanger the optimization process is a key stage due to economical considerations.
In recent years, the research in the field of thermal hydraulic at a microscale level has been constantly increasing due to the rapid growth of the technology applications that require the transfer of high heat rates in a relatively small space and volume. Such applications spread from compact heat exchangers to cooling systems for computer CPU to micro fluidic devices. Generally, the classical thermal and fluid dynamic theories developed for macro systems are not applicable to fluids in a microscale structure. Investigations on the heat transfer in a capillary are the basis for designing micro- and high-efficiency heat transfer equipment, such as micro heat pipes (MHPs). Two-phase flow Patterns are also greatly affecting the design and prediction of performance of the refrigeration cycle. Properties such as density, heat capacity, viscosity, thermal conductivity, enthalpy, entropy…etc, must be known in order to design the cycle and for dimensioning heat exchangers. One of the major challenges for CO2 refrigeration systems is to improve the performance of heat exchangers. It is worth mentioning that most of these early works on flow boiling of CO2 were performed for large diamete
Heat exchangers play a vital role in almost all fields of industry ranging from condensers and evaporators in refrigerating units to radiators of automobiles . The strive for obtaining better energy efficiency and cost savings has made the industry to constantly upgrade the technology associated with heat exchangers to improve their heat transfer efficency , reduce the size and also to lower production costs .This has resulted in research into various tube shapes used in heat exchagers including wing-shaped tubes that can improve the heat exchange efficiency .A study was carried out to compare the performance of heat exchangers with staggered banks of tubes with wing-shaped cross sections and cylindrical tubes under turbulent flow conditions. Detailed 2D- numerical simulations of fluid flow and heat transfer were performed for various pitch to diameter ratios using Computational Fluid Dynamics . When compared to the normal cylindrical tubes better heat exchange was observed in wing-shaped tubes which could be due to more attached flow happening in this case due to the wing-shape.
This book deals with the modeling and simulation of spiral coil heat exchanger, one of the most promising compact heat exchanger. Its design provides the advantages of high turbulence, high heat-transfer coefficients and high fouling resistance. High heat-transfer coefficients allow smaller heat-transfer areas compared to traditional shell-and-tube heat exchangers used for the same duty. This ultimately results in significant size reductions and weight savings as less material is needed to construct the unit.In this book firstly various type of compact heat exchanger used in industries are discussed. After it a brief over view of the research work is presented then modelling and simulation of spiral coil heat exchanger using MS-Excel is done.
TWO - PHASE FLOW : Heat transfer involving two phases such as liquid-gas is of vital importance especially in petrochemical and allied industries. The presence of a gas phase along with liquid alters not only the fluid dynamic behavior but also the heat transfer characteristics namely, the heat transfer coefficient. Two-phase flow is considered to be the common class of multiphase flow. The phases commonly involved are liquids, gases and solids and their combinations such as gas-liquid, gas-solid, liquid-liquid and solid-liquid. SHELL & TUBE HEAT EXCHANGER : The most common type of heat exchanger used in an industry contains a number of parallel tubes enclosed in a shell called as shell and tube heat exchanger. These heat exchangers are employed when a process requires large quantities of fluid to be heated or cooled. Due to their compact design these heat exchangers contain a large heat transfer area and also provide a high degree of heat transfer efficiency. Heat exchanger is an essential unit in heat extraction and recovery systems with an increasing emphasis on energy savings.