Therefore, the fin effectiveness can be determined easily when the fin efficiency is known, or vice versa. The rate of heat transfer from a sufficiently long fin or uniform cross section under steady conditions is given by Equation 3.34. Substituting this relation into Equation 3.40, the effectiveness of such a long fin is determined to be
The concentric tube heat exchanger was designed in order to study the process of heat transfer between two fluids through a solid partition. It was designed for a counter-flow arrangement and the logarithmic mean temperature difference (LMTD) method of analysis was adopted. Water was used as fluid for the experiment.
A double pipe heat exchanger consists of one pipe inside another. It can be operated as a parallel flow or as a counterflow heat exchanger. Double pipe heat exchanger design requires use of the heat transfer rate, the log mean temperature difference, and an estimate of the overall heat transfer coefficient to calculate the estimated heat transfer surface area.
Shell-and-tube heat exchangers can have multiple passes, such as 1-1, 1-2, 1-4, 1-6, and 1-8 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes. An odd number of tube passes is seldom used except the 1-1 exchanger. A 1-2 shell-and-tube heat exchanger is illustrated in Figure 5.19.
To design or predict the performance of a heat exchanger, the LMTD and the eﬀectiveness-NTU methods are both useful. I'll ﬁrst touch on the LMTD method, to give you an overview of its derivation and meaning. One circumstance in designing or predicting the performance of a hxgr is the need to relate the heat
84 The -NTU Method Therefore, the maximum possible heat transfer rate in heat exchanger is: ( ) in c in h T T C Q,, min max = ` h c C or C of smaller the is C where min: 85 The -NTU Method Therefore the heat exchanger effectiveness for a counter-flow heat exchanger is: ( ) ( ) ( ) ( ) in c in h out h in h h in c in h in c out c c T T C T T C T .
NPTEL Video Lectures, IIT Video Lectures Online, NPTEL Youtube Lectures, Free Video Lectures, NPTEL Online Courses, Youtube IIT Videos NPTEL Courses. . Mod-07 Lec-31 Effectiveness-NTU, method of heat exchanger analysis. Mod-07 Lec-32 Design of double pipe heat exchanger.
Heat exchanger effectiveness is defined as the ratio of the actual amount of heat transferred to the maximum possible amount of heat that could be transferred with an infinite area. Two common methods are used to calculate the effectiveness, equations and graphical. The equations are shown below:
In the previous section we discussed heat transfer in a differential segment of the heat exchanger. Here, we analyze the heat transfer in the entire heat exchanger. Heat exchangers are usually analyzed using either the Logarithmic Mean Temperature Difference (LMTD) or the Effectiveness – Number of Transfer Units (ε-NTU) methods.
The mechanical design of a shell and tube heat exchanger provides information on items such as shell thickness, flange thickness, etc. These are calculated using a pressure vessel design code such as the Boiler and Pressure Vessel code from ASME (American Society of Mechanical Engineers) and the British Master Pressure Vessel Standard, BS 5500.
What is the difference between the Effectiveness-NTU and LMTD Methods for analyzing heat exchangers? By Jeff Sines, Senior Product Engineer, Engineered Software, Inc. As with any engineering problem, there are various ways to approach a solution when sizing and selecting a heat exchanger or analyzing its thermal performance.
Indian Institute of Technology Bombay and NPTEL via Swayam. 0 Reviews 62 students interested. Facebook Twitter . The Overall Heat Transfer Coefficient, Heat Exchanger Analysis: Use of the Log Mean Temperature Difference, Heat Exchanger Analysis: The Effectiveness–NTU Method, Heat Exchanger Design and Performance Calculations .
Heat Recovery Efficiency - Classification of heat recovery efficiency - temperature efficiency, moisture efficiency and enthalpy efficiency - online heat exchanger efficiency calculator; Overall Heat Transfer Coefficient - Calculate overall heat transfer coefficients for walls or heat exchangers; Overall Heat Transfer Coefficients for Fluids .
Nov 11, 2015· Heat exchanger are used to transfer heat, there are few methods to calculate rate of heat transfer LMTD method (when you know temp's of fluid) but when you are not aware of temp, The NTU method is used especially in Counter flow Heat Exchanger .
Heat Exchangers 73 individual thermal resistances of the system. Combining each of these resistances in series gives: 1 UA = 1 (ηohA)i 1 Skw 1 (ηohA)o (5.7) where η0 is the surface eﬃciency of inner and outer surfaces, h is the heat transfer coeﬃcients for the inner and outer surfaces, and S …
Mar 22, 2016· THE EFFECTIVENESS–NTU METHOD The log mean temperature difference (LMTD) method discussed in Section 23–4 is easy to use in heat exchanger analysis when the inlet and the outlet temperatures of the hot and cold fluids are known or can be determined from an energy balance.
The NTU-effectiveness design method [I], commonly used in two-fluid heat exchanger design, was extended by Sortie  to the restricted case of three-fluid heat exchangers of the concentric-tube and plate-fin types, in which the intermediate and cold streams were thermally isolated from each other.
Fin-Tube Heat Exchanger Optimization 349 where I0 and K 0 are modified, zero-order Bessel functions of the first and second kind respectively. Assuming the constant and known base temperature and zero heat flow through the tip of
The other fluid would change temperature more quickly along the heat exchanger length. The method, at this point, is concerned only with the fluid undergoing the maximum temperature change. The effectiveness (), is the ratio between the actual heat transfer …
effectiveness of heat exchanger nptel,
Effectiveness Concept for Heat Exchangers The Design Equation for a Heat Exchanger Q H = UA ∆ T 2 – ∆ T 1 ln ∆ T 2 ∆ T 1 = UA ∆ T lm A typical problem in the analysis of a heat exchanger is the Performance calculation. That is, we are asked, given inlet conditions to evaluate how the exchanger performs, that is what are the outlet .
Heat Exchanger Effectiveness (NTU method) If more than one of the inlet and outlet temperature of the heat exchanger is unknown, LMTD may be obtained by trial and errors solution. Another approach introduce the definition of heat exchanger effectiveness (Є), which is a dimensionless with ranging between 0 to1. .
Dec 11, 2008· Lecture Series on Heat and Mass Transfer by Prof. S.P.Sukhatme and Prof. U.N.Gaitonde, Department of Mechanical Engineering, IIT Bombay. For more details on .
LMTD Correction Factor Chart NimishShah 2 The LMTD method is very suitable for determining the size of a heat exchanger to realize prescribed outlet temperatures when the mass flow rates and the inlet and outlet temperatures of the hot and cold fluids are specified. With the LMTD method, the task is to select a heat
NPTEL – Chemical Engineering – Chemical Engineering Design - II Joint initiative of IITs and IISc – Funded by MHRD Page 33 of 41 Lecture 6: Condenser and Reboiler Design 18.104.22.168. Pressure drop calculation i. Tube side pressure drop In case of tube side condensation: . of design of shell and tube heat exchanger for single phase.
Double Pipe Heat Exchanger Calculation does the thermal and hydraulic design of double pipe heat exchangers and estimate number of Hairpin required. CheCalc Chemical engineering calculations to assist process, plant operation and maintenance engineers.
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ü basic heat exchanger flow arrangements. ü log mean temperature differences. ü applications for counter and parallel flows. ü multipass flow arrangements. ü effectiveness – ntu method. module - 8:- boiling and condensation.
The main basic Heat Exchanger equation is: Q = U x A x ΔTm The log mean temperature difference ΔTm is: ΔTm = (T1 – t2) – (T2 – t1) = (°C) (°F). Where: T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature; T2 = Outlet tu.
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Each heat exchanger is a bespoke product, designed by iteration and consultation with customers to provide optimal cost and performance (i.e. pressure drop/effectiveness). This paper discusses the design and surface enhancement considerations that lead to optimal heat exchanger designs.
A heat exchanger can have several different flow patterns. Crossflow, parallel flow, and counterflow heat exchanger configurations are three examples. A counterflow heat exchanger will require less heat exchange surface area than a parallel flow heat exchanger for the same heat transfer rate and the same inlet and outlet temperatures for the fluids.