scholarly journals Kaji efisiensi temperatur penukar panas dengan variasi aliran untuk aplikasi pengering

2018 ◽  
Vol 16 (2) ◽  
pp. 39
Author(s):  
Syukran Syukran
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Fluid Phase ◽  
Parallel Flow ◽  
Small Scale ◽  
Counter Flow ◽  
Flow Type ◽  
Temperature Efficiency

Abstrak Heat exchanger atau alat penukar panas adalah alat-alat yang digunakan untuk mengubah temperatur fluida atau mengubah fasa fluida dengan cara mempertukarkan panasnya dengan fluida lain. Pada sebuah penukar panas kemampuan mempertukarkan panas sangat ditentukan oleh tipe dan jenis aliran fluida yang melewati penukar panas. Secara garis besar penukar panas dibagi berdasarkan arah aliran fluidanya. Berdasarkan arah aliran fluida penukar panas  dibedakan menjadi 3 (tiga) jenis aliran, yaitu aliran searah (parallel flow), aliran berlawanan (counter flow) dan aliran silang (cross flow). Saat ini penukar panas banyak dipakai dalam  industri pengeringan produk-produk pertanian, perkebunan dan perikanan skala kecil dan menengah. Penggunaan penukar panas dalam bidang pengeringan saat ini sudah menjadi kebutuhan untuk mengatasi permasalahan produktifitas pengeringan. Umumnya penukar panas yang digunakan adalah tipe aliran berlawanan. Beberapa penelitian telah dilakukan untuk mengetahui efektifitas penukar panas tersebut yang umumnya berfokus pada jenis aliran berlawanan. Penelitian penelitian spesifik yang mengkaji perbandingan efisiensi penukar panas  untuk ketiga jenis aliran belum ditemukan. Penelitian ini dilakukan untuk mengetahui efisiensi temperatur penukar panas untuk jenis aliran jenis aliran melintang, sejajar, dan  berlawanan. Metode penelitian dilakukan fabrikasi 3 unit exchanger tipe gas-gas dengan dimensi 50 (P) x 10 (L) x 30 (T) dengan jumlah tube 17 susunan. Hasil  penelitian menunjukkan bahwa efisiensi temperatur untuk ketiga jenis penukar panas tersebut adalah 21,3% aliran melintang, 17,3% aliran berlawanan dan 15,9%  aliran sejajar. Hasil penelitian menyimpulkan bahwa efisiensi temperatur tertinggi diperoleh jenis penukar panas aliran melintang. Kata kunci : Penukar panas, aliran sejajar, aliran berlawanan, aliran silang, temperatur.  Abstrack Heat exchangers or heat exchangers are the means used to change the temperature of the fluid or to change the fluid phase by exchanging heat with other fluids. In a heat exchanger the heat exchange ability is greatly determined by the type and type of fluid flow passing through the heat exchanger. Broadly speaking the exchanger is divided based on the direction of fluid flow. Based on the direction of fluid flow exchanger is divided into 3 (three) types of flow, namely parallel flow, counter flow and cross flow. Currently, heat exchangers are widely used in the drying industry of small and medium-sized agricultural and small-scale plantation and fishery products. The use of exchangers in the field of drying is now a need to overcome the problems of drying productivity. Generally the exchanger used is the opposite flow type (counter flow). Several studies have been conducted to determine the effectiveness of these exchangers which generally focus on the opposite type of flow. Specific research studies that reviewed the efficiency of exchangers for the three types of flow have not been found. This research was conducted to find out the efficiency of heat exchanger temperature for flow type of cross flow, parallel flow and counter flow type. The research method was fabricated 3 units of gas-gas exchanger type with dimension 50 (P) x 10 (L) x 30 (T) with the number of tubes 17 staggered arrangement. The results show that the temperature efficiency for the three types of heat exchanger is 21.3% cross flow flow, 17.3% flow counter flow and 15.9% parallel flow flow. The results concluded that the highest temperature efficiency obtained by cross flow flow type exchanger. Keywords: Heat exchanger, parallel flow, counter flow, cross flow, temperature

Study on A Cross Flow Type of Heat Exchanger : counter flow version with heat transfer enhancement

2004 ◽  
Vol 2004.14 (0) ◽  
pp. 331-334
Author(s):  
Kazuhiko SATO ◽  
Hiroshi KUROTANI ◽  
Himsar Ambarita ◽  
Jun SUZUKI ◽  
Norihiko KAMADA ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Cross Flow ◽  
Transfer Enhancement ◽  
Counter Flow ◽  
Flow Type

A Transient Model for Parallel Flow and Counter Flow Heat Exchangers

2013 ◽  
Author(s):  
K. Abbasi ◽  
M. Del Valle ◽  
A. P. Wemhoff ◽  
A. Ortega
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Transient Behavior ◽  
Parallel Flow ◽  
Thermal Mass ◽  
Dimensionless Time ◽  
Internal Wall ◽  
Counter Flow ◽  
Thermal Capacitance ◽  
Flow Heat

The transient and steady-state response of single pass constant-flow (concentric parallel flow, concentric counter flow) heat exchangers was investigated using a finite volume method. Heat exchanger transients initiated by both step-change and sinusoidally varying hot stream inlet temperatures were investigated. The wall separating the fluid streams was modeled by conduction with thermal mass; hence the heat exchanger transient behavior is dependent on the thermal mass of the fluid streams as well as the internal wall. The outer wall is approximated as fully insulating. The time dependent temperature profiles were investigated as a function of heat exchanger dimensionless length and dimensionless time for both fluids. It was found that the transient response of the heat exchanger is controlled by a combination of the residence time and thermal capacitance of the fluid streams, the overall heat transfer coefficient between the fluid streams, and the thermal capacitance of the internal wall.

Effectiveness-NTU Relations for Heat Exchangers With Streams Having Significant Kinetic Energy Variation

2003 ◽  
Vol 125 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Gregory F. Nellis
Keyword(s):  
Heat Exchanger ◽  
Kinetic Energy ◽  
Differential Equations ◽  
Heat Exchangers ◽  
Parallel Flow ◽  
Temperature Profiles ◽  
Cryogenic Temperatures ◽  
Cold Side ◽  
Counter Flow ◽  
Flow Heat

Effectiveness-NTU equations are derived for counter and parallel-flow heat exchangers with fluids having high velocities. In this case, the change in the kinetic energy occurring within the heat exchanger will significantly affect the temperature profiles. The effectiveness is found to depend on the usual non-dimensional variables that compare the heat exchanger conductance to the hot- and cold-side capacity rates and on four additional nondimensional quantities that reflect the magnitude and distribution of the kinetic energy on the hot and cold-sides of the heat exchanger. The governing differential equations are derived, nondimensionalized, and solved analytically for the case of an exponentially distributed kinetic energy. Graphical solutions are presented and interpreted for several cases. The solutions are applied to a particular case involving high velocities within a counter-flow heat exchanger used to produce cryogenic temperatures.

EXERGO-ECONOMIC PERFORMANCE EVALUATION ON LOW TEMPERATURE HEAT EXCHANGER

2005 ◽  
Vol 19 (01n03) ◽  
pp. 517-519 ◽  
Author(s):  
S. Y. WU ◽  
Y. R. LI ◽  
D. L. ZENG
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Economic Performance ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Counter Flow ◽  
Flow Process ◽  
Economic Criterion ◽  
Net Profit ◽  
Temperature Heat

Based on the exergo-economic analysis of low temperature heat exchanger heat transfer and flow process, a new exergo-economic criterion which is defined as the net profit per unit heat flux for cryogenic exergy recovery low temperature heat exchangers is put forward. The application of criterion is illustrated by the evaluation of down-flow, counter-flow and cross-flow low temperature heat exchangers performance.

scholarly journals KAJI EKSPERIMENTAL PENGARUH BAFFLE PADA ALAT PENUKAR PANAS ALIRAN SEARAH DALAM UPAYA OPTIMASI SISTEM PENGERING

2019 ◽  
Vol 13 (1) ◽  
pp. 8
Author(s):  
Azwinur Azwinur ◽  
Zulkifli Zulkifli
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Fluid Phase ◽  
Field Testing ◽  
Heat Losses ◽  
Cooling Fluid ◽  
Directional Flow ◽  
Drying System ◽  
Guide Blade

Heat exchangers or heat exchangers are tools used to change the temperature of the fluid or change the fluid phase by exchanging heat with another fluid. In a heat exchanger, the ability to exchange heat is largely determined by the type of fluid flow and fluid passing through the heat exchanger. The use of heat exchangers in the field of drying is now a necessity to overcome the problems of drying productivity. The purpose of this study was carried out to determine the effectiveness of the heat exchanger experimentally based on directional flow by comparing construction using baffle and without using baffle in an effort to optimize the drying system. The research method was carried out by fabricating 2 units of heat exchangers and by field testing. The test data obtained are the input and output temperatures of the heating fluid flow and cooling fluid flow and flow velocity. Based on preliminary research data shows that the use of baffle affects the increase in temperature on the heat exchanger, where at the fresh air outlet that does not use baffle produces a temperature of 72oC while the baffle produces 88oC with the Log Mean Temperature Difference heat exchanger without using a baffle higher than heat exchanger that uses a baffle guide blade. This can illustrate that the smaller heat losses are wasted so that the absorption of heat by the reverse system will be higher.

A Constant-Wall-Temperature Model for Prediction of Thermal Performance of Gas-to-Gas Counter-Flow and Parallel-Flow Microchannel Heat Exchangers

2011 ◽  
Author(s):  
Kohei Koyama
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Difference Method ◽  
Heat Exchangers ◽  
Parallel Flow ◽  
Counter Flow ◽  
Partition Wall ◽  
Transfer Rates ◽  
Flow Configuration ◽  
Microchannel Heat Exchanger

Thermal performances of gas-to-gas counter-flow and parallel-flow microchannel heat exchanger have been investigated. Working fluid used is air. Heat transfer rates of both heat exchangers are compared with those calculated by a conventional log-mean temperature difference method. The results show that the log-mean temperature difference method can be employed to a parallel-flow configuration whereas that cannot be employed to a counter-flow configuration. This study focuses on the partition wall which separates hot and cold passages of the microchannel heat exchanger. The partition wall is negligibly thin for a conventional-sized heat exchanger. In contrast, the partition wall is thick compared with channel dimensions for a microchannel heat exchanger. A model which includes the effect of the thick partition wall is proposed to predict thermal performances of the microchannel heat exchangers. The heat transfer rates obtained by the model agree well with those obtained by the experiments. Thermal performances of the counter-flow and parallel-flow microchannel heat exchangers are compared with respect to one another based on temperature of the partition wall. The comparison results show that thermal performances of the counter-flow and parallel-flow microchannel heat exchangers are identical. This is due to performance degradation induced by the thick partition wall of the counter-flow microchannel heat exchanger. This study reveals that the thick partition wall dominates thermal performance of a gas-to-gas microchannel heat exchanger.

Thermal Efficiency of the Cross Flow Heat Exchangers

2006 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Cross Flow ◽  
Algebraic Expression ◽  
Counter Flow ◽  
Optimum Heat ◽  
Flow Heat

The heat exchanger efficiency is defined as the ratio of the actual heat transfer in a heat exchanger to the optimum heat transfer rate. The optimum heat transfer rate, qopt, is given by the product of UA and the Arithmetic Mean Temperature Difference, which is the difference between the average temperatures of hot and cold fluids. The actual rate of heat transfer in a heat exchanger is always less than this optimum value, which takes place in an ideal balanced counter flow heat exchanger. It has been shown that for parallel flow, counter flow, and shell and tube heat exchanger the efficiency is only a function of a single nondimensional parameter called Fin Analogy Number. The function defining the efficiency of these heat exchangers is identical to that of a constant area fin with an insulated tip. This paper presents exact expressions for the efficiencies of the different cross flow heat exchangers. It is shown that by generalizing the definition of Fa, very accurate results can be obtained by using the same algebraic expression, or a single algebraic expression can be used to assess the performance of a variety of commonly used heat exchangers.

Numerical analysis of compact plate-fin heat exchangers for aerospace applications

2018 ◽  
Vol 28 (2) ◽  
pp. 395-412 ◽  
Author(s):  
Ranganayakulu Chennu
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Conduction ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Design Data ◽  
Content Type ◽  
Compact Heat Exchangers ◽  
Performance Deterioration

Purpose The purpose of this study is to find the thermo-hydraulic performances of compact heat exchangers (CHE’s), which are strongly depending upon the prediction of performance of various types of heat transfer surfaces such as offset strip fins, wavy fins, rectangular fins, triangular fins, triangular and rectangular perforated fins in terms of Colburn “j” and Fanning friction “f” factors. Design/methodology/approach Numerical methods play a major role for analysis of compact plate-fin heat exchangers, which are cost-effective and fast. This paper presents the on-going research and work carried out earlier for single-phase steady-state heat transfer and pressure drop analysis on CHE passages and fins. An analysis of a cross-flow plate-fin compact heat exchanger, accounting for the individual effects of two-dimensional longitudinal heat conduction through the exchanger wall, inlet fluid flow maldistribution and inlet temperature non-uniformity are carried out using a Finite Element Method (FEM). Findings The performance deterioration of high-efficiency cross-flow plate-fin compact heat exchangers have been reviewed with the combined effects of wall longitudinal heat conduction and inlet fluid flow/temperature non-uniformity using a dedicated FEM analysis. It is found that the performance deterioration is quite significant in some typical applications due to the effects of wall longitudinal heat conduction and inlet fluid flow non-uniformity on cross-flow plate-fin heat exchangers. A Computational Fluid Dynamics (CFD) program FLUENT has been used to predict the design data in terms of “j” and “f” factors for plate-fin heat exchanger fins. The suitable design data are generated using CFD analysis covering the laminar, transition and turbulent flow regimes for various types of fins. Originality/value The correlations for the friction factor “f” and Colburn factor “j” have been found to be good. The correlations can be used by the heat exchanger designers and can reduce the number of tests and modification of the prototype to a minimum for similar applications and types of fins.

Exergy Transfer Effectiveness on Heat Exchanger

2006 ◽  
Author(s):  
Shuang-Ying Wu ◽  
Xiao-Feng Yuan ◽  
You-Rong Li ◽  
Wen-Zhi Cui ◽  
Liao Quan
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Counter Flow ◽  
Temperature Heat ◽  
Relevant Variables ◽  
Flow Heat ◽  
Exergy Transfer

In this paper, the concept of exergy transfer effectiveness is put forward firstly and the expressions involving relevant variables for the exergy transfer effectiveness, the heat transfer units number and the ratio of cold and hot fluids heat capacity rate have been derived for the high and low temperature heat exchangers. Taking the parallel flow, counter flow and cross flow heat exchangers as examples, the numerical results of exergy transfer effectiveness are given and the comparison of exergy transfer effectiveness with heat transfer effectiveness is analyzed.

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