scholarly journals FEATURES OF LIQUID FLOW DISTRIBUTION IN PLATE HEAT EXCHANGERS REFERENCES

Author(s):  
Y. Elistratova ◽  
A. Seminenko ◽  
V. Minko ◽  
R. Ramazanov

The relevance of the work of information and diagnostic systems in the field of monitoring of plate heat exchange equipment is considered. The reliability of the monitoring devices requires an accurate mathematical description of the thermo hydrodynamic processes in the heat exchange channels. The classical description of these processes implies a uniform distribution of the flow rate of the working medium along the length of the plate package, which in turn implies equal conditions for the formation of salt deposition products on the heating surfaces of the plate heat exchanger. The use of dependencies that take into account the equality of costs for a package of plates reduces the reliability of diagnostics of the efficiency of hot water devices of the plate type. Since the geometric space formed by the plates is represented by parallel channels connected by sections of transit collectors, the method of resistance characteristics is proposed as a method of hydraulic calculation of the distribution features of liquid flows through heat exchange channels. The dependence of the design features of the location of the interplate channels relative to the input of the coolant into the distribution manifold is revealed. It is found that, the flow rate of the circulating coolant is less in the channels most remote from the inlet pipe than in the nearest channels. The hypothesis of the influence of the relative position of the channels in relation to the inlet pipe is confirmed by numerical studies of the hydrodynamic regime of the plate heat exchanger.

2008 ◽  
Vol 12 (3) ◽  
pp. 85-90 ◽  
Author(s):  
Rangasamy Rajavel ◽  
Kaliannagounder Saravanan

In this paper, the heat transfer coefficients in a spiral plate heat exchanger are investigated. The test section consists of a plate of width 0.3150 m, thickness 0.001 m and mean hydraulic diameter of 0.01 m. The mass flow rate of hot water (hot fluid) is varying from 0.5 to 0.8 kg/s and the mass flow rate of cold water (cold fluid) varies from 0.4 to 0.7 kg/s. Experiments have been conducted by varying the mass flow rate, temperature, and pressure of cold fluid, keeping the mass flow rate of hot fluid constant. The effects of relevant parameters on spiral plate heat exchanger are investigated. The data obtained from the experimental study are compared with the theoretical data. Besides, a new correlation for the Nusselt number which can be used for practical applications is proposed.


Author(s):  
Л. А. Кущев ◽  
В. Н. Мелькумов ◽  
Н. Ю. Саввин

Постановка задачи. Рассматривается теплообменный процесс, протекающий в модифицированном гофрированном межпластинном канале интенсифицированного пластинчатого теплообменного аппарата с повышенной турбулизацией теплоносителя. Необходимо разработать компьютерную модель движения теплоносителя в диапазоне скоростей 0,1-1,5 м/с и определить коэффициент турбулизации пластинчатого теплообменника. Результаты. Приведены результаты компьютерного моделирования движения теплоносителя в межпластинном гофрированном канале оригинального пластинчатого теплообменного аппарата с помощью программного комплекса Аnsys . Определены критерии устойчивости системы. Выполнено 3 D -моделирование канала, образуемого гофрированными пластинами. При исследовании процесса турбулизации были рассмотрены несколько скоростных режимов движения теплоносителя. Определен коэффициент турбулизации Tu, %. Выводы. В результате компьютерного моделирования установлено увеличение коэффициента теплопередачи К, Вт/(м ℃ ) за счет повышенной турбулизации потока, что приводит к снижению металлоемкости и уменьшению стоимости теплообменного оборудования. Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1-1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined. Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.


2015 ◽  
Vol 55 (4) ◽  
pp. 267 ◽  
Author(s):  
Jan Skočilas ◽  
Ievgen Palaziuk

<p>This paper deals with a computational fluid dynamics (CFD) simulation of the heat transfer process during turbulent hot water flow between two chevron plates in a plate heat exchanger. A three-dimensional model with the simplified geometry of two cross-corrugated channels provided by chevron plates, taking into account the inlet and outlet ports, has been designed for the numerical study. The numerical model was based on the shear-stress transport (SST) <em>k-!</em> model. The basic characteristics of the heat exchanger, as values of heat transfer coefficient and pressure drop, have been investigated. A comparative analysis of analytical calculation results, based on experimental data obtained from literature, and of the results obtained by numerical simulation, has been carried out. The coefficients and the exponents in the design equations for the considered plates have been arranged by using simulation results. The influence on the main flow parameters of the corrugation inclination angle relative to the flow direction has been taken into account. An analysis of the temperature distribution across the plates has been carried out, and it has shown the presence of zones with higher heat losses and low fluid flow intensity.</p>


Author(s):  
L. A. Kushchev ◽  
V. N. Melkumov ◽  
N. Yu. Savvin

Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1--1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined.Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m2 ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8280
Author(s):  
Jeonggyun Ham ◽  
Gonghee Lee ◽  
Dong-wook Oh ◽  
Honghyun Cho

In this study, computational fluid dynamics (CFD) analysis was performed to investigate the cause of the thermal stratification in the channel and the temperature non-uniformity of the plate heat exchanger. The flow velocity maldistribution of the channel and the merging parts caused temperature non-uniformity in the channel width direction. The non-uniformity of flow velocity and temperature in the channel is shown in Section 1 > Section 3 > Section 2 from the heat exchanger. The non-uniform temperature distribution in the channel caused channel stratification and non-uniform outlet temperature. Stratification occurred at the channel near the merging due to the flow rate non-uniformity in the channel. In particular, as the mass flow rate increased from 0.03 to 0.12 kg/s and the effectiveness increased from 0.436 to 0.615, the cold-side stratified volume decreased from 4.06 to 3.7 cm3, and the temperature difference between the stratified area and the outlet decreased from 1.21 K to 0.61 K. The increase in mass flow and the decrease in temperature difference between the cold and hot sides alleviated the non-uniformity of the outlet temperature due to the increase in effectiveness. Besides, as the inlet temperature difference between the cold and the hot side increases, the temperature non-uniformity at the outlet port is poor due to the increase in the stratified region at the channel, and the distance to obtain a uniform temperature in the outlet pipe increases as the temperature at the hot side increases.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shiva Singh ◽  
Piyush Verma ◽  
Subrata Kumar Ghosh

Purpose This study aims to present the experimental and computational performance analysis in compact plate heat exchanger (PHE) using graphene oxide nanofluids at different concentrations and flow rate. Design/methodology/approach Field emission scanning electron microscope and X-ray diffraction were used to characterize graphene oxide nanoparticles. The nanofluid samples were prepared by varying volume concentration. Zeta potential test was done to check stability of samples. The thermophysical properties of samples have been experimentally measured. The experimental setup of PHE with 60° chevron angle has also been developed. The numerical analysis is done using computational fluid dynamics (CFD) model having similar geometry as of the actual plate. Distilled water at fixed temperature and flow rate is used in hot side tank. Nanofluid at fixed temperature with varying concentration and flow rate is used in cold side tank as coolant. Findings The numerical and experimental results were compared and found that both results were in good agreement. The results showed ∼13% improvement in thermal conductivity, ∼14% heat transfer rate (HTR), ∼9% in effectiveness and ∼10% in overall heat transfer coefficient at cost of pressure drop and pumping power using nanofluid. Exergy loss also decreased using nanofluid at optimum concentration of 1 Vol.%. Originality/value The CFD model can be significant to analyze temperature, pressure and flow distribution in heat exchanger which is impossible otherwise. This study gives ease to predict PHE performance with high accuracy without performing the experiment.


Author(s):  
Ryan Crowell

Threats of climate change and depleted petroleum supplies have prompted the need for eco-conscious alternative energy. This paper introduces a ground-breaking concept for harnessing the sun’s power that is significantly more efficient than existing systems. Solar collectors gather the electromagnetic radiation emitted by the sun and heat a propylene glycol to a high temperature that will then transfer the heat to a working fluid (Care30) through a plate heat exchanger. The Care30 then exits the heat exchanger in a gaseous state, and is passed through a Tesla turbine, which in turn rotates a shaft. The shaft is connected to a generator, which transforms the mechanical energy into electricity. The absorption efficiency of the solar collectors allows for mechanical loses while maintaining the overall efficiency at higher levels than any existing PV based system. Ambient temperatures drastically reduce the effectiveness of flat plate solar collectors, cooling the liquids inside before the heat can be efficiently consumed. In contrast, an evacuated tube collector maintains efficiency during such conditions. The collectors are insulated from ambient temperatures by the vacuum pressure inside the tube. A stainless steel flat plate heat exchanger is used to transfer the heat from the glycol/water solution to the refrigerant, which is sent to the turbine after it has been converted to its gaseous state. The solution also provides freeze protection in colder climates. A heat exchanger then cools the gas, returning it to its liquid state, which completes the cycle for the working fluid. The water used in the heat exchanger is then used as a supplementary heating source for the home, for domestic or radiant heating needs. As it is effective even in environments that compromise the functionality of existing PV systems, the proposed system responds effectively to the need for more efficient alternative energy sources.


2014 ◽  
Vol 584-586 ◽  
pp. 728-731
Author(s):  
Ming Hui Cui ◽  
Xin Wang ◽  
Ji Liang Liu

Plate heat exchanger with unique advantages become dominant heat exchange equipment in heating engineering. But there is no heating regulation formula of plate exchanger applying in indirect connection hot water heating central heating regulation. This paper analysis the condition that the heating user’s system adopts quality regulation method and the hot water network system adopts quality-flow regulation method, obtain the regulation formulas of plate exchanger applying in indirect connection hot water heating central heating regulation, provides reliable theory basis on the operation regulation, energy –saving testing, etc. for indirect connection central heating system.


Author(s):  
L. A. Kushchev ◽  
V. A. Uvarov ◽  
N. Yu. Savvin ◽  
S. V. Chuikin

Statement of the problem. The problem of intensification of heat exchange processes in a plate heat exchanger on the basis of the HH№ 02 heat exchanger of the Ridan company is discussed. It is essential to carry out an analysis of the existing methods of intensification of heat exchange processes in plate devices according to the results of the analysis to choose the most promising method of intensification of heat exchange process and based on it to develop a patent-protected design of a heat exchange plate. Laboratory tests of the intensified plate heat exchanger with increased turbulence of the coolant are performed. The results of thermal tests on a specialized laboratory installation of the resulting and the serial heat exchanger are presented.Results. The results of the comparison of experimental studies of the intensified plate heat exchanger with the increased turbulence of the heat carrier and the serial plate heat exchanger of identical heat power are shown. The graphs of dependence of the heat transfer coefficient, which is the major characteristic of the operation of heat exchange equipment, on the average temperature pressure are designed. Conclusions. As a result of the laboratory tests in the specialized laboratory of BSTU named after V. G. Shukhov and research at the Voronezh State Technical University established a rise in the heat transfer coefficient due to the increased turbulence of the coolant flow, which causes a decrease in metal consumption and reduces the cost of heat exchange equipment.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2137 ◽  
Author(s):  
Jorge Chan ◽  
Roberto Best ◽  
Jesús Cerezo ◽  
Mario Barrera ◽  
Francisco Lezama

Absorption systems are a sustainable solution as solar driven air conditioning devices in places with warm climatic conditions, however, the reliability of these systems must be improved. The absorbing component has a significant effect on the cycle performance, as this process is complex and needs efficient heat exchangers. This paper presents an experimental study of a bubble mode absorption in a plate heat exchanger (PHE)-type absorber with NH3-LiNO3 using a vapor distributor in order to increase the mass transfer at solar cooling operating conditions. The vapor distributor had a diameter of 0.005 m with five perforations distributed uniformly along the tube. Experiments were carried out using a corrugated plate heat exchanger model NB51, with three channels, where the ammonia vapor was injected in a bubble mode into the solution in the central channel. The range of solution concentrations and mass flow rates of the dilute solution were from 35 to 50% weight and 11.69 to 35.46 × 10−3 kg·s−1, respectively. The mass flow rate of ammonia vapor was from 0.79 to 4.92 × 10−3 kg·s−1 and the mass flow rate of cooling water was fixed at 0.31 kg·s−1. The results achieved for the absorbed flux was 0.015 to 0.024 kg m−2·s−1 and the values obtained for the mass transfer coefficient were in the order of 0.036 to 0.059 m·s−1. The solution heat transfer coefficient values were obtained from 0.9 to 1.8 kW·m−2·K−1 under transition conditions and from 0.96 to 3.16 kW·m−2·K−1 at turbulent conditions. Nusselt number correlations were obtained based on experimental data during the absorption process with the NH3-LiNO3 working pair.


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