Premium Essay

Heat Transfer and Its Applications

In: Science

Submitted By aoemastr
Words 312
Pages 2
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and heat between physical systems. As such, heat transfer is involved in almost every sector of the economy.[1] Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system.
Heat conduction, also called diffusion, is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems. When an object is at a different temperature from another body or its surroundings, heat flows so that the body and the surroundings reach the same temperature, at which point they are in thermal equilibrium. Such spontaneous heat transfer always occurs from a region of high temperature to another region of lower temperature, as described by the second law of thermodynamics.
Heat convection occurs when bulk flow of a fluid (gas or liquid) carries heat along with the flow of matter in the fluid. The flow of fluid may be forced by external processes, or sometimes (in gravitational fields) by buoyancy forces caused when thermal energy expands the fluid (for example in a fire plume), thus influencing its own transfer. The latter process is often called "natural convection". All convective processes also move heat partly by diffusion, as well. Another form of convection is forced convection. In this case the fluid is forced to flow by use of a pump, fan or other mechanical means.
Thermal radiation occurs through a vacuum or any transparent medium (solid or fluid). It is the transfer of energy by means of...

Similar Documents

Premium Essay

Double Pipe Heat Exchanger

...CFD Analysis of two pass Double Pipe Heat Exchanger with Fe3O4/water Nano fluid Dissertation submitted In partial fulfilment of requirement For the award of degree of Master of Technology in Thermal Engineering by Ponnada Prasanthkumar 13131D2102 Under the Guidance of Sri B. Ajit Assistant Professor Department of Mechanical Engineering GAYATRI VIDYA PARISHAD COLLEGE OF ENGINEERING (AUTONOMOUS) (Affiliated to J.N.T. University, Kakinada) VISHAKHAPATNAM - 530048 CERTIFICATE This is to certify that the project titled CFD Analysis of Double Pipe two pass Heat Exchanger with Fe3O4/water Nano fluid is a bonafide record of the work done by Ponnada Prasanthkumar (13131D2102) In partial fulfilment of the requirements for the award of the degree of Master of Technology in Thermal Engineering of the Gayatri Vidya...

Words: 7433 - Pages: 30

Premium Essay

Essay On Heat Exchanger

...CHAPTER – 1 Introduction:- Heat exchangers are very helpful in chemical process, engineering application and also in daily use applications, such as, dairy industry, chemical industry, environment engineering, power production, air conditioning and also in food industry. Shell & Tube heat exchanger is commonly used in energy industries and petrochemical industry. Plate Heat Exchanger is commonly used in a wide range of chemical process and so many industrial functions. So many effort have been made to increase the heat transfer of heat exchanger, reduce the heat transfer time and also increase the energy utilization. The mixture of fluid (base liquid) and Nanoparticles (nanometer sized) are called 'nanofluid'. Latest technology gives benefit...

Words: 1646 - Pages: 7

Free Essay

Classification of Heat Exchangers

...Classification Of Heat Exchangers Introduction Heat: is energy in transit from one mass to another because of a temperature difference between the two. A form of energy associated with the motion of atoms or molecules and transferred from a body at a higher temperature to one at a lower temperature. Heat energy will move from a high energy state to that of a lower energy state. The process will continue until a state of equilibrium is reached. Equilibrium is the energy state where the material is at the same energy level as its surroundings. A heat exchanger is defined as device used to transfer thermal energy (enthalpy) between two or more fluids, between the solid surface and a fluid. The fluids can be single compounds or mixtures. The typical applications of heat exchangers include cooling or heating of fluid stream of concern, evaporation or condensation of multi-component or single fluid stream. They are also used in heat rejection or heat recovery from a system. The heat exchanger: Is a piece of equipment built for efficient heat transfer from one medium to another? The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. Heat exchangers are found in most chemical or mechanical systems. They serve as the system's means of gaining or rejecting heat. Some of the more common applications are found in heating, ventilation and air conditioning (HVAC) systems, radiators on internal combustion engines, boilers, condensers,...

Words: 828 - Pages: 4

Free Essay

Process Technology

...Mike Voss PCT 105 Equipment April 5, 2012 Heat Exchangers There are many types of heat exchangers used in a wide variety of industrial applications including power plants, boilers for industrial steam, chemical plants, and many types of manufacturing facilities. Several different configurations are used to accomplish the function of transferring heat from one fluid to another without mixing the two fluids together. The two most common industrial heat exchangers, the shell and tube heat exchanger and the double pipe heat exchanger, along with information about spiral heat exchangers, flat plate heat exchangers, flat plate heat exchangers, fin-tube heat exchangers, and condensers. Calculations for heat exchanger design use heat transfer parameters such as convection heat transfer coefficients, overall heat transfer coefficients, and log mean temperature differences. These calculations are needed for shell and tube and double pipe heat exchangers, as well as other types. The flow pattern through a heat exchanger affects the required heat exchanger surface. A counter flow heat exchanger needs the lowest heat transfer surface area. It gives a higher value for log mean temperature difference than either a parallel flow heat exchanger or a cross flow heat exchanger. A heat exchanger can have several different flow patterns. Counter flow, parallel flow, and crosss flow are common heat exchanger types. A counter flow heat exchanger is the most efficient flow......

Words: 1476 - Pages: 6

Free Essay

Adsorption Heat Pumps Using the Zeolite-Water Pair

...Impianti chimici II Monographic Thesis ADSORPTION HEAT PUMPS USING THE ZEOLITE-WATER PAIR: Operating principle and applications Author: Federica FURNARI 1 SUMMARY Introduction ___________________________________________________________________ 3 Chapter 1 Why choosing water-zeolite? ____________________________________________________ 5 Chapter 2 Operating principle of water-zeolite heat pump ____________________________________ 8 Chapter 3 Technological applications _____________________________________________________ 11 Solar-powered adsorption icemakers _____________________________________________________ 12 Self chilling beer kegs _________________________________________________________________ 15 Solar-powered adsorption air conditioners ________________________________________________ 16 Chapter 4 Key issues for future development _______________________________________________ 18 The heat/mass transfer issue ___________________________________________________________ 19 Heat recovery _______________________________________________________________________ 21 Bibliography _________________________________________________________________ 24 2 Introduction Although adsorptive processes have been extensively studied for gas separation, catalysis, etc., it is only recently that they have been proposed for heat management. The interest in adsorption systems started to increase, firstly due to the oil crisis in the 1970s that lead......

Words: 4863 - Pages: 20

Free Essay

Heat Exchangers

...------------------------------------------------- Temperature controlled applications In a temperature control application, the inlet temperature of the secondary fluid to the heat exchanger may change with time. This means that in order to maintain a consistent secondary fluid outlet temperature, the heat supplied to the heat exchanger must also vary. This can be achieved by using a control valve on the inlet to the primary side of the heat exchanger, as shown in Figure 13.2.1. Fig. 13.2.1 Typical temperature control of a steam/water shell and tube heat exchanger A control valve is used to vary the flowrate and pressure of the steam so that the heat input to the heat exchanger can be controlled. Modulating the position of the control valve then controls the outlet temperature of the secondary fluid. A sensor on the secondary fluid outlet monitors its temperature, and provides a signal for the controller. The controller compares the actual temperature with the set temperature and, as a result, signals the actuator to adjust the position of the control valve. For a constant heating area and heat transfer coefficient, the rate at which heat is transferred from the steam to the secondary fluid for a particular heat exchanger is determined by the mean temperature difference between the two fluids. A larger difference in mean temperatures will create a large heat transfer rate and vice versa. On partially closing the control valve, the steam pressure and the temperature......

Words: 4745 - Pages: 19

Premium Essay


...Method and theory of 3D micro heat pipe cooling introduction: The traditional heat dissipation method has included different parts, such as Air cooling and Water cooling. When IC chip generate heat in working on a high level, there has to be some methods to reduce heat make sure that the chips will not be damaged. With some theory [Surface area of evaporator, Heat input in Watt act.] there are several advanced method and theory of 3D micro heat pipe cooling. Key word: LPMHP, Tube transfer ,Moore's Law ,Heat-Pipe, Fluids, Cooling rate. Method and theory in experimental A experimental study has been performed to investigate the heat transfer characteristics of looped parallel micro heat pipes of circular geometry having inner diameter of 1.8mm and length of 150mm placed parallel, connected by two U tubes of same diameter at the top and bottom ends. The experimental parameters are condenser inclination angel, heat input and properties of the working fluids. Taking acetone and ethanol as working fluids, heat transfer characteristics are determined experimentally for different condenser inclination angels a different heat input. With the advancement of micro and nanotechnologies, the power densities in the electronic equipments are increasing rapidly. Overheating of integrated circuit(IC),microchip etc. It is very important to facilitate optimum cooling of electronic components in a smaller electronic device because integrated circuit lifetime......

Words: 1006 - Pages: 5

Premium Essay

Heat Transfer Studies

...Chapter 1 INTRODUCTION The project ‘Heat Transfer Studies on a 7.5 Watt LED Lighting Load using Finite Element Analysis’ is mainly concerned with the heat generated by an LED lighting load and its dissipation to the surrounding such that the LED junction temperature is maintained low. The LED chosen for this project is 7.5 Watt, which has a maximum operating temperature of around 80°C, exceeding which the LED will fail. The LED is best operated at room temperature conditions and may be just above. The project implements a specific method of cooling or rather maintaining the LED junction temperature as low as possible by using a Thermo Electric Cooling device, more specifically known as the Peltier device. The project looks into the various methods by which a Peltier cooler can be implemented such as, with or without a fan or simply a fan would provide sufficient cooling for the LED module. A Heat sink is a necessary component which is always associated with cooling electronic components. Before getting into the depth of the project detailing we will look into the basic components that have been used in the project setup which include: a. LED Module b. Peltier Cooler c. Heat Sink d. Cooling Fan 1.1 Light Emitting Diode: Light-emitting diodes (LEDs) are small but powerful devices in terms of their diverse applications. LED lights assume greater significance in the context of need for electrical energy conservation and pollution control world over. LED is......

Words: 12034 - Pages: 49

Free Essay

Design of a Finned Radiator Assembly

...Finned Radiator Assembly | Heat Exchanger Design Project | Thien Van TranChris LongfieldEric PacewiczOlivia Ching | | 4/3/2012 | | Scope of the Project The objective of the project was to design an effective radiator assembly to accommodate the Diesel-Engine Generator Set 1500-XC6DT2 by incorporating the use of tubes with inner fins in various geometries in order to meet the heat rejection requirements specified. This was done with consideration for minimizing cost, size, and complexity. Initial Parameters The initial parameters were the operating requirements of the Diesel-Engine Generator Set 1500-XC6DT2 are as follows: * Coolant capacity – The coolant chosen for our radiator is ethylene glycol (50/50 % by volume) * Its maximum operating temperature of 225F * Air flow rate – Since the generator is stationary as opposed to that used in an automobile application, a fan will be needed to provide the necessary flow rate. The required air flow rate specified by the engine is 9.383 m3/s in order to dissipate the heat generated * Coolant flow rate – The coolant flow rate is 17.914 kg/s through the radiator * The initial coolant temperature is assumed to be 212F, which is slightly below the operating temperature of the engine. The initial coolant temperature is taken as the ethylene glycol entering the radiator immediately after leaving the engine. * Pressure drop allowance – The * The total heat rejected to the coolant is......

Words: 1400 - Pages: 6

Premium Essay

Sublimation Print

...the Impact of Dye – Sublimation Printing on the Effectiveness of Underwear Raziskava vpliva sublimacijskega tiska na učinkovitost spodnjega perila Original Scientific Paper/Izvirni znanstveni članek Received/Prispelo 02-2014 • Accepted/Sprejeto 04-2014 Abstract This study deals with the effect of dye-sublimation printing on the performance of underwear. Two groups of polyester knitted fabrics were analysed. The change of tree selected groups of properties was investigated before and after the application of dye-sublimation printing, namely durability (breaking force and elongation, abrasion resistance and pilling resistance), physiological properties (water vapour permeability, air permeability) and colour-fastness (resistance to rubbing, to domestic and commercial laundering, to perspiration). Further, the structure changes of fabrics (thickness and density) during heat pressing both without application of dyes (without transfer printing on material) and with application of dyes were also studied to analyse the affect extent of printing conditions (particularly pressure and temperature) on total wear comfort printed fabrics. The results show that the tested materials meet requirements in terms of colour-fastness to rubbing, to domestic and commercial laundering and to perspiration to a very high standard (grade 5). In terms of abrasion resistance and pilling resistance the material also showed high resistance. The air permeability for both fabrics decreased by......

Words: 3480 - Pages: 14

Free Essay


...Background of the Study Heat exchangers have been used extensively and play an important role in the capital cost, energy efficiency and physical size of refrigeration and air conditioning systems. In this dissertation, a simulation tools to improve effectiveness and efficiency in design, rating, and analysis of air to refrigerant heat exchangers including conventional finned tube coils and emerging micro channel heat exchanger, Coil Designers, is developed and investigated using a general-purpose modeling concept and user friendly interface. The basic concept of a heat exchanger is based on the premise that the loss of heat on the high temperature side is exactly the same as the heat gained in the low temperature side after the heat and mass flow through the heat exchanger. Heat exchanger ‘simply’ exchanges the heat between those two sides; as a result, it is decreasing the temperature of higher temperature and increasing the temperature of lower temperature side. But designing heat exchanger might a challenge; it needs iteration for manual calculation. Many factors have to be considered in heat exchanger selection. Generally suitability of types of heat exchanger to be used in processing industrials is selected based on TEMA (Tubular Exchanger Manufacturer Association) Standards. TEMA divides heat exchanger into classes based on their application. A shell a tube heat exchanger is one of the standards designs of heat exchanger. It is most common types of heat exchanger......

Words: 398 - Pages: 2

Premium Essay

Nao Fluids Case Study Solution

...CHAPTER-2 NANO FLUIDS Nano fluids are a new kind of approach for heat transfer applications. Nano fluids are containing nanoparticles having size of 1–100 nm, which are uniformly and stably suspended in a base fluid. Generally metals or metal-oxides used as Nanoparticles and they greatly enhance the thermal conductivity of the Nano fluids. Nano fluids have been considered for so many industrial applications for advanced heat transfer fluids for two decades. However, due to complexity of the Nano fluid systems, there is no agreement has been achieved in heat transfer processes. Nano fluids have the following advantages: • Nano fluids have broad surface area and more heat transfer rate occurs between particles and base fluids. • High dispersal...

Words: 1131 - Pages: 5

Premium Essay

Axiomatic Design Approach for Design of Nano Fluids

...Available online at Applied Thermal Engineering 29 (2009) 75–90 An axiomatic design approach in development of nanofluid coolants In Cheol Bang a,*, Gyunyoung Heo b b a Energy Sciences, Global Edge Institute, Tokyo Institute of Technology, 2-12-1-S6-13 O-okayama, Meguro-ku, Tokyo 152-8550, Japan Department of Nuclear Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyunggi-do 446-701, Republic of Korea Received 4 September 2007; accepted 4 February 2008 Available online 12 February 2008 Abstract The experimental data for nanofluids in thermal-fluid systems have shown that the new fluids promise to become advanced heat transfer fluids in terms of thermal performance. While enhancing thermal characteristics, the solid–liquid mixtures present an unavoidable disadvantage in terms of pumping cost for economic operation of thermal-fluid systems. In addition, there is a lack of agreement between experimental data provided in the literature. The present work found that there would be no comprehensible design strategy in developing nanofluids. In this work, the Axiomatic Design (AD) theory is applied to systemize the design of nanofluids in order to bring its practical use forward. According to the Independence Axiom of the AD theory, the excessive couplings between the functional requirements and the parameters of a nanofluid system prevent from meeting the functional goals of the......

Words: 7984 - Pages: 32

Premium Essay

Chem Sys

...SHELL & TUBE HEAT EXCHANGER DESIGN TFD-HE13 - Shell & Tube Heat Exchager Design 1 Introduction q Shell & tube heat exchangers are the most versatile type of heat exchangers. § They are used in process industries, in conventional and nuclear power stations, steam generators, etc § They are used in many alternative energy applications including ocean, thermal and geothermal. q Shell & tube heat exchangers provide relatively large ratios of heat transfer area to volume. They can be easily cleaned. q TFD-HE13 - Shell & Tube Heat Exchager Design 2 Shell & Tube Heat Exchangers q Shell & tube type heat exchangers are built of tubes (round or rectangular in general) mounted in shells (cylindrical, rectangular or arbitrary shape). Many variations of this basic type is available. q § The differences lie mainly in the detailed features of construction and provisions for differential thermal expansion between the tubes and the shell. Shell inlet Tube inlet Tube outlet Shell outlet TFD-HE13 - Shell & Tube Heat Exchager Design 3 Shell & Tube Heat Exchangers U-Tube, baffled, single pass shell & tube heat exchanger Two pass tube, baffled single pass shell & tube heat exchanger Two pass tube, floating head, baffled single pass shell & tube heat exchanger TFD-HE13 - Shell & Tube Heat Exchager Design 4 Shell Types q q TEMA (the Tubular Exchangers Manufacturers Association) publishes standards defining......

Words: 5860 - Pages: 24

Premium Essay

Heat Transfer

...HEAT TRANSFER Essay 1 Heat is one of many forms of energy that can be transformed into each other in accordance with the First Law of Thermodynamics. However, it is important to note that the energy contained within any substance cannot be regarded as heat. In fact, heat only exists when it is transferred between two media and then only due to a temperature difference between those media. There are many misuses of the word “heat”. It is not uncommon to describe the temperature in an oven as being 350 degrees of heat. Also, the energy contained in a medium is sometimes said to be the heat contained within that medium. These uses, as well as other misuses, are excluded by the definition: heat is energy in transit due to a temperature difference. Heat transfer is one of the most ubiquitous processes in nature. It is also commonly encountered in virtually all devices, machines, instruments, and living creatures. With such a broad range of application, heat transfer becomes a key part of the engineering knowledge base. Like most undergraduate subjects, the subject matter taught in heat transfer courses represents the academic view of the topic. That view is highly sanitized and drastically simplified compared with reality. The homework problems in the typical undergraduate course are also contrived to be solvable by use of the knowledge base that is conveyed in standard textbooks and in the classroom. Expertise in solving such problems is misleading because those......

Words: 464 - Pages: 2