Pdf computational fluid dynamics analysis of shell and. Therefore the log mean temperature for a counter flow heat exchanger is larger than the log mean temperature for a similar parallel or. The overall heat transfer coefficient was found to be 59% higher than that of parallel flow at 0. A counterflow heat exchanger is the most efficient flow pattern of the three.
Allow sufficient time for thermal equilibrium to attain between hot and cold water 7. Heat transfer equation sheet heat conduction rate equations fouriers law. However, in this experiment the focus is only on parallel flow and counter flow inside the concentric pipe. Nassar 2 preface the purpose of this manual is to make it easy for students to perform simple experiments in heat transfer. This is why, the pdf books that we presented always the books taking into account amazing reasons. Parallel flow counter flow heat exchanger apparatus 11. A counter flow or countercurrent shell and tube heat exchanger s construction is in many ways identical to that of a parallel flow shell and tube heat exchanger. Therefore, it can not be classified as a compact heat exchanger. If the flow pattern is more complex such as the case with most shell and tube heat exchangers, then a correction factor term is used and the. Oscillatory flow and heat transfer within parallelplate. Combining each of these resistances in series gives. The earliest development of phes was in response to. Heat exchanger efficiency 4 has also been defined on the basis of efficiency of a fin of a constant area with its tip insulated, as a a f tanhf 3 where f a is the heat exchanger number and is expressed as, 2 ntu1 r f a for counter flow heat exchanger fand for parallel flow 2 ntu1 r a where ntu is the number of transfer units. Lets take the case when we want to extract the maximum amount of heat from a given hot stream.
For parallel flow, also known as cocurrent flow, both. The wet heat exchanger has a higher effectiveness in counter flow than parallel flow. The schematic and the temperature profile of the fluid streams in parallel flow heat exchanger are shown in fig. Heat transfer laboratory annajah national university. Plate heat exchanger, how it works working principle hvac industrial engineering phx heat transfer duration. Up to this point we have learned how to analyze conduction and con vection heat transfer in various systems with different geometries. Oscillatory flow and heat transfer within parallel plate heat exchangers of thermoacoustic systems fatimah a. If heat capacity rates of the cold and hot fluids are the same and the heat exchanger is operated in the counterflow regime then. One fluid hot convectively transfers heat to the tube wall where conduction takes place across the tube to the opposite wall.
Heat exchanger lab report free download as word doc. Parallel flow heat exchanger in parallel flow heat exchangers, the two mediums enter the exchanger at the same end, and travel in parallel to one. Pdf design and development of parallel counter flow heat. Counter flow exists when the two fluids flow in opposite directions. Parallel and counter flow heat exchangers heat exchanger. Pdf heat exchanger lab experiment chemical engineering. A heat exchanger is a device in the habit of transfer heat between a solid. If there is an additional resistance either in series or in parallel, then replace with in all the above lumped ca. However, in this experiment, we only consider the counter flow heat exchanger and parallel flow. There are probably heat exchanger in your office building which heat transfer from hot water to the ventilation system in the winter and from the indoor air to the. Pdf design and development of parallel counter flow. Heat transfer processes set limits to the performance of aerospace components and systems and the subject is one of an enormous range of application. Introduction the plate heat exchanger phe experiment uses common equipment found in heat exchange processes used in industries such as. From the calculations resulting in overall effectiveness, it is shown that the counter flow heat exchanger is more effective than the parallel flow heat exchanger.
Design and development of parallel counter flow heat exchanger. Why is a counter flow heat exchanger better than a. Parallel and counter flow heat exchangers heat exchanger flow. In a parallel flow heat exchanger, the working fluids flow in. Heat exchanger lab report laws of thermodynamics heat. To understand the basic operation of heat exchangers.
Thermal conductivity measurement of pipe insulation using lagged pipe apparatus. Che245 lab report solteq concentric tube heat exchanger. In parallel flow, both the hot and cold fluids enter the heat exchanger at the same end and move in the same direction, as shown in figure 1. In this experiment, we focused on the shell and tube heat exchanger. Lets assume we have a perfectly efficient, infinitely long heat exchanger with the same substance on each side, but one enters at 100 f and the other at 0 f. The inlet temperature of cooled fluid has insignificant impact on heat exchanger effectiveness. Difference in counter and parallel flow heat exchanger. Thermal conductivity measurement using guarded plate apparatus. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions in a concentric tube or doublepipe construction. The student will perform use tem perature and flow rate measurements to. There are 3 types of heat exchanger, parallel flow, counter flow, and cross flow.
Whether parallel or counterflow, heat transfer within the heat exchanger involves both conduction and convection. Parallel flow, counter flow, heat transfer coefficient, lmtd, effectiveness. Heat exchangers 73 individual thermal resistances of the system. Cfd resolve the entire heat exchanger in discrete elements to find. Determination of heat transfer coefficient under natural convection from a vertical cylinder. Counter and parallel flow heat exchangers citeseerx.
The main difference is that the tubeside fluid enters the exchanger at. In a parallel flow heat exchanger, the two fluid streams hot and cold flow through the heat exchanger in the. Parallel and counter flow heat exchanger two types of flow arrangement are possible in a doublepipe heat exchanger. Parallel and counter flow heat exchanger lab experiment.
The objective of this experiment is to calculate the rate of the heat transfer log mean temperature difference, and the overall heat transfer coefficient in case of parallel flow. This heat exchanger uses a spiraling inner copper tube, depicted in fig. Jaworski o proceedings of the world congress on engineering 20 vol iii. Table 7 experiment results of copper double pipe heat exchanger parallel flow. Introduction a heat exchanger is a device originally developed for heat transfer between two fluids at. The experiments start with both hot and cold fluids enter the heat exchanger at the same end and move in the same direction in parallel flow cocurrent. Keywords energy balance, heat transfer, overall heat transfer coefficient i.
For example, refrigerators use heat exchangers to heat transfer from your groceries to the surrounding air. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions. The two fluid streams enter at one end of the heat exchanger and leave at the other end. Heattransfer characteristics of wet heat exchangers in. Heat exchangers are typically classified according to flow arrangement and type of construction. It is found that the overall heat transfer coefficient of counter flow was 48% higher than that of parallel flow at 0. The efficiency of a counter flow heat exchanger is due to the fact that the average t difference in temperature between the two fluids over the length of the heat exchanger is maximized, as shown in figure 4.
Unfortunately, the flow in most heat exchangers is so complicated that a simple. Experimental study on parallel and counter flow configuration of a. Similar expressions may be obtained for a parallel flow heat exchanger. Difference in counter heat exchanger and parallel flow. Parallel flow heat exchanger in a parallel flow heat exchanger, the two fluid streams hot and cold flow through the heat exchanger in the same direction. Counter flow heat exchanger for cross flow and shellandtube heat exchangers. This heat exchanger consists of two concentric pipes of different diameters.
Types of heat transfer devices are heat exchanger he, heat. Changing the airflow along the tunnel is done by a variable speed axial fan, the values of which are measured by a differential micromanometer. The types of heat exchangers to be tested in this experiment are called singlepass, parallel flow and counter flow concentric tube heat exchangers. Concentric tube heat exchanger emd5mia page 2 fluid and transfer it into the cold fluid. Nassar, phd, peng department of chemical engineering annajah national university. Introduction to engineering heat transfer these notes provide an introduction to engineering heat transfer. Heat exchanger lab report heat exchanger heat transfer scribd. Adjust the desired flow rate of water either parallel counter flow heat exchanger. It leads to the lowest required heat exchanger surface area because the log mean temperature drop is the highest for a counterflow. Counterflow, parallel flow, and crossflow are common heat exchanger types. T is independent of position in the heat exchanger. In this research work, experiments were conducted on various types of heat exchangers to compare their efficiencies, effectiveness and over all. Comparison of heat exchanger types each of the three types of heat exchangers parallel, cross and counter flow has advantages and disadvantages.
The heat is then convectively transferred to the second fluid. Whats the difference between parallel flow, counter flow. Equation is used when simple counter or cocurrent flows exist. Experimental investigation of parallel and counter flow heat. Download as doc, pdf, txt or read online from scribd. Heat exchangers jordan university of science and technology.
The experimental set up in this investigation consists of a parallel flow heat exchanger. One part of this experiment involves measurements using the enhanced concentric tube heat exchanger in which the fluids flow in a countercurrent fashion. This supports generally held knowledge and experimental data concerning the two types of heat exchanger, governed by the clausius statement. Three types of fluid motion direction inside the heat exchanger are parallel flow, counter flow and cross flow. The following degrees of freedom can be varied in this experiment. What is parallelflow and counterflow heat exchanger. The manual presents detailed descriptions of experiments. But of the three, the counter flow heat exchanger design is the most efficient when comparing heat transfer rate per unit surface area. Heat exchanger transfer thermal energy from one medium to another. A heat exchanger can have several different flow patterns.
Parallel and counter flow heat exchangers free download as pdf file. Effectiveness and efficiency analysis of parallel flow and. Switch on the electric geyser set the hot water temperature say 50 to 60 c. A heat exchanger is a device by which thermal energy is transferred from one fluid to another.
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