Performance Of Plate Heat Exchanger Research Articles

Numerical Simulation of Corrugated Depth on the Performance of Plate Heat Exchanger

In this paper the numerical simulation is performed by using the CFD soft FLUENT. A 3D geometric model is established and whose mesh is generated. The fields of the temperature, pressure and velocity in the computational domain are simulated. And the effect of the corrugation depth on the heat transfer and flow is analyzed.

Heat transfer performance and exergy analyses of a corrugated plate heat exchanger using metal oxide nanofluids

Heat exchangers have been widely used for efficient heat transfer from one medium to another. Nanofluids are potential coolants, which can afford excellent thermal performance in heat exchangers. This study examined the effects of water and CuO/water nanofluids (as coolants) on heat transfer coefficient, heat transfer rate, frictional loss, pressure drop, pumping power and exergy destruction in the corrugated plate heat exchanger. The heat transfer coefficient of CuO/water nanofluids increased about 18.50 to 27.20% with the enhancement of nanoparticles volume concentration from 0.50 to 1.50% compared to water. Moreover, improvement in heat transfer rate was observed for nanofluids. On the other hand, exergy loss was reduced by 24% employing nanofluids as a heat transfer medium with comparing to conventional fluid. Besides, 34% higher exergetic heat transfer effectiveness was found for 1.5vol.% of nanoparticles. It has a small penalty in the pumping power. Hence, the plate heat exchanger performance can be improved by adapting the working fluid with CuO/water nanofluids.

The influence of plate corrugations geometry on plate heat exchanger performance in specified process conditions

The mathematical model of plate heat exchanger (PHE) is developed using decomposition of the plate on its main corrugated field, which cause major effect on heat transfer, and distribution zone, which influences mostly the hydraulic performance. Model is validated on experimental data for some commercial plates. It is shown, that for specified pressure drop, temperature program and heat load the geometrical parameters of plate and its corrugations, which are enable to make PHE with minimal heat transfer area, can be found. The developed mathematical model can be used for designing of plates with geometry, which is in the best way satisfying process conditions of the certain specific range. The case study for conditions of PHE application in District Heating systems is presented.

The effect of using nano-particles on corrugated plate heat exchanger performance

The application of nano-fluids is thought to have a strong potential for enhancing the heat transfer characteristics of the corrugated plate heat exchanger-PHE. The corrugated PHE is one of the most versatile and wide using types of heat exchangers. In this study, an experimental test loop has been constructed to study the PHE thermal characteristics; heat transfer coefficient, effectiveness, transmitted power and pressure drop at different concentrated volume fractions of AL2O3 nano-material (1–4%) in pure liquid water as a base fluid. The measured heat transfer coefficient results were compared and verified against a theoretical model, a reasonable consistence was noticed. A pronounced increase in both the heat transfer coefficient and the transmitted power was observed by increasing the nano-material concentration. The maximum increase in heat transfer coefficient is reached 13% for a nano-fluid concentration of 4% vol. However, the increase in heat transfer coefficient is up to 13% under an uncertainty of 9.8%, at constant Re number. If it is compared at constant flow rate, this marginal enhancement will be further reduced. So the application of nano-fluids as a strong potential for enhancing the heat transfer in the corrugated PHE is doubtful for the current study. Both the pressure drop and the required pumping power were increased with the increase in nanofluid concentration and Reynolds number value. The maximum increase in pressure drop was recorded 45% above the base fluid value at 4% vol. of nanofluid, while the pumping power was recorded 90% higher due to the dual effect of increase in both the pressure drop and the volumetric flow, where the constant Reynolds number condition requires more volumetric flow to compensate the kinematic viscosity effect on Reynolds number. A further research work for the same field is required to remove the inauspicious between different researchers.

Thermal and hydraulic performance of sinusoidal corrugated plate heat exchanger for low temperature lift heat pump

Thermal and hydraulic performance of a sinusoidal corrugated plate heat exchanger (PHX) was investigated for the application of a low temperature lift heat pump (LTLHP), which requires unique operating conditions. The water-side heat transfer coefficient and pressure drop of the PHX were obtained through the experimental test. The refrigerant-side heat transfer performance was investigated by varying several parameters. The PHX performance was poor due to low refrigerant mass flux. The PHX needs better balance in two fluids for the LTLHP application. From the current study, it is concluded that the conventional PHX applied for the LTLHP application is limited by two main factors: a large pressure drop on the water-side due to corrugated shape, and a low heat transfer performance due to the low refrigerant-side heat transfer performance. In order to address these drawbacks, heat exchanger designs must be improved by optimizing its geometry and flow area asymmetrically for each fluid.

성능 예측 상관식에 따른 쉐브론 형태 판형 열교환기 성능 특성 비교

The performance of a plate heat exchanger for using liquid solution in the absorp- tion chiller-heater was analyzed. The model was developed by using the various performance prediction correlations. The performance characteristics of the plate heat exchanger with the mass flow rate ratio was verified by using experimental data. To investigate performance of plate heat exchanger with geometry variables, the chevron angle, corrugated wave length, and corrugation depth were changed. As a result, the capacity of Kim and Martin correlation models was similar with the experimental data, and the capacity difference was less than 2%. Besides, the pressure drop of Marin correlation model showed a similar variation with experimental data, and the difference of pressure drop was less than 1.5 kPa.

The Use of a Nano- and Microporous Surface Layer to Enhance Boiling in a Plate Heat Exchanger

Presented research is an experimental study of the performance of a standard plate heat exchanger evaporator, both with and without a novel nano- and microporous copper structure, used to enhance the boiling heat transfer mechanism in the refrigerant channel. Various distance frames in the refrigerant channel were also employed to study the influence of the refrigerant mass flux on two-phase flow heat transfer. The tests were conducted at heat fluxes ranging between 4.5 kW/m2 and 17 kW/m2 with 134a as refrigerant. Pool boiling tests of the enhancement structure, under similar conditions and at various surface inclination angles, were also performed for reasons of comparison. The plate heat exchanger with the enhancement structure displayed up to ten times enhanced heat transfer coefficient in the refrigerant channel, resulting in an improvement in the overall heat transfer coefficient with over 100%. This significant boiling enhancement is in agreement with previous pool boiling experiments and confirms that the enhancement structure may be used to enhance the performance of plate heat exchangers. A simple superposition model was used to evaluate the results, and it was found that, primarily, the convective boiling mechanism was affected by the distance frames in the standard heat exchanger. On the other hand, with the enhanced boiling structure, variations in hydraulic diameter in the refrigerant channel caused a significant change in the nucleate boiling mechanism, which accounted for the largest effect on the heat transfer performance.

쉐브론 각도변화에 따른 판형 고온 용액열교환기의 성능평가

The objectives of this paper are to measure the heat transfer and pressure drop of the plate heat exchangers for absorption system applications. Three types of plate heat exchangers with different chevron angles are tested in the present experiment. Heat transfer and pressure drop performance of plate heat exchangers are measured in various operating conditions, and compared each other. The results show that the heat transfer rate of high theta (120°) and mixed theta plate heat exchanger increases about 118% and 98% at the solution flow rate 350 ㎏/h compared to that of low theta (60°), respectively. The effectiveness of high theta was evaluated about 0.53 ~ 0.85 in this experimental range. The experimental correlations of the Nu and f were developed with error bands of ±7% and ±12%.

Combined Experimental and Simulation (CFD) Analysis on Thermal Performance of Plate Heat Exchanger Using Kerosene as Working Fluid

The plate heat exchanger exhibits excellent heat transfer characteristic, which allows a very compact design with ease of maintenance and modification of heat transfer area by adding (or) removing plates. Constructional parameters such as flow path, trough angle and corrugation can affect the performance of plate heat exchangers by altering effectiveness (?) and number of transfer unit (NTU). Especially plate heat exchangers play a vital role in petroleum industries for wide range of temperature application. Hence, it was proposed to choose kerosene as cold fluid and hot water as hot fluid in this present investigation. A vertical type of plate heat exchanger, in which flow pattern is maintained as co-current, has been used to conduct the experimental runs. The numbers of plates in the plate heat exchanger used in the present study are 10. The number of flow channels (space maintained between two consecutive channels) allocated for both fluids are 9. Experimental runs have been conducted for different combinations of hot fluid flow rates and cold fluid flow rates for single phase flow, in which hot water is considered as hot streams and kerosene as cold fluid. The thermal performance of plate heat exchanger has been analyzed based on calculated parameters using experimental data set. A similar corrugated plate heat exchanger model having the same dimensions as that of the experimental one was developed with aid of CFD tool. The model was simulated at different operating conditions and compared with experimental results. The simulated results are in good agreement with experimental data. The percentage deviation between experimental results and simulation results for over all heat transfer coefficient is less than ±6%.

Effects of dissipation and temperature-dependent viscosity on the performance of plate heat exchangers

The fluid temperature profiles in a multi-passage plate heat exchanger and its effectiveness were calculated with a model which includes dissipation, temperature-dependent viscosity and appropriate correlations for the Nusselt number and the friction coefficient. When the viscosity of the two fluids is low (e.g. water) the results are identical to the classic ε– NTU relations which are obtained by neglecting dissipation and by assuming that fluid properties and heat transfer coefficients are constant. But, when one of the fluids is very viscous (e.g. glycerol) the temperatures of both fluids are significantly higher while the effectiveness can be higher or lower than the value predicted by the classic relations. In particular, for cases with a very viscous hot fluid, the effectiveness may be even higher than unity.

Numerical Analysis of Plate Heat Exchanger Performance in Co-Current Fluid Flow Configuration

Numerical Analysis of Plate Heat Exchanger Performance in Co-Current Fluid Flow Configuration

Dynamics of plate heat exchangers subject to flow variations

A predictive model has been presented to suggest the transient response of plate heat exchangers, subjected to a step flow variation. The work also brings out the effect of the port to channel maldistribution on the performance of plate heat exchangers under the condition of flow variation. The results indicate that flow maldistribution affects the performance of the plate heat exchangers in the transient regime. A wide range of the parametric study has been presented which brings out the effects of NTU and heat capacity rate ratio on the response of the plate heat exchanger, subjected flow perturbation. To verify the presented theoretical model, appropriate experiments have been carried out. Experiments include the responses of the outlet temperatures subjected to inlet temperature transient in the circuit followed by a sudden change in flow rate in one of the fluids. Simulated performance has been compared to the performance measured in the experiments. Comparisons indicate that theoretical model developed for flow transient is capable of predicting the transient performance of the plate heat exchangers satisfactorily, under the given conditions of changed flow rates.

Application of numerical methods to study the effect of variable fluid viscosity on the performance of plate heat exchangers

Purpose – The purpose of this paper is to investigate numerically the influence of variable fluid viscosity on thermal characteristics of plate heat exchangers for counter‐flow and steady‐state conditions.Design/methodology/approach – The approach to fulfill the purpose of the paper is to derive the one‐dimensional energy balance equations for the cold and hot streams in the adjacent channels of a plate heat exchange composed of four corrugated plates. A finite difference method has been used to calculate the temperature distribution and thermal performance of the exchanger. Water is used as the hot liquid being cooled in the side channels, while a number of working fluids whose viscosity variation versus temperature is more severe were used as the cold fluid being heated in the central channel.Findings – The program is run for a combination of working fluids such as water‐water, water‐isooctane, water‐benzene, water‐glycerin and water‐gasoline. The temperature distributions of both streams have been plot...

Performance of Plate Heat Exchangers for Evaporation of Ammonia

Measurements on a semi-welded plate heat exchanger (PHE) and on various versions of the nickel-brazed PHE were performed in a large experimental refrigeration rig. Experiments were carried out with the refrigerant ammonia, which was completely evaporated in vertical upward flow in PHEs connected in a U-type manner. A multiple linear regression analysis produced three Nusselt number correlations for the different PHEs that can predict the measured Nusselt number decently. The values for the C-coefficient (in the correlation of the two-phase multiplier) for the higher Reynolds number are somewhat higher than those reported in other investigations. An inlet flow distributor in the semi-welded heat exchanger made it possible to achieve a higher performance at low ΔT out. The nickel-brazed heat exchanger with an integrated inlet flow distributor was found to have a better performance compared to a nickel-brazed heat exchanger without the flow distributor.

Application of numerical methods to study the effect of axial conduction in plates and flow channels on the performance of plate heat exchangers

PurposeThe purpose of this paper is to predict the plate heat exchanger performance when axial conduction in plates and in flow channels are present and fluids' viscosities are temperature dependent.Design/methodology/approachThe approach to achieve the objective of the paper is deriving the governing equations and developing a computer program based on finite differences to solve them. The governing equations become dimensionless defining reference values and then discretized using FTBCS and FTCS methods. To solve the governing equations, the flow channel is divided into small elements in axial direction. Physical properties are constant for each element, while viscosity changes from one element to another one.FindingsThe effect of axial conduction in plates as well as in flow channels on temperature distributions, are studied individually and simultaneously. The program is run under four different conditions, namely: no axial conduction, axial conduction in the plates and in the flow channels, axial conduction in the plates only, and axial conduction in the flow channels only.In all the above cases, temperature distributions are achieved and characteristic curves are plotted. The numerical results are validated by comparing them with those published in an established reference carried out ignoring the effect of axial conduction, using the same plate geometry and flow details.Originality/valueThis paper gives valuable information and offers practical help to plate heat exchanger design engineer in order to choose the proper material for the plates as well as the right service and product fluids.

A 2D dynamic model for fouling performance of plate heat exchangers

A 2D fouling model for milk pasteurizer using plate heat exchangers (PHEs) was implemented and validated. The model emphasis was placed on fouling prediction based on the hydrodynamic and thermodynamic performances of PHEs in 2D environment. Different types of multichannel PHEs, i.e. 12-channel PHE 1 and 20-channel PHE 2 with both counter-current and co-current flows were applied to validate the model by visualization and quantification of milk deposit developed in the fluid channels. The predicted mass deposit values at each channel were in good agreement with the experimental data with the average prediction error of 0.4 g or 10.9% ( R 2 = 0.98) for PHE 1. The theoretical values of temperature and mass deposit for a plate of PHE 2 were closer to the actual measurements with errors of 1.6 °C or 2.1% and 0.06 g or 6%, respectively. The aggregation rate of unfolded protein was observed to increase exponentially with increasing wall temperature, due to a reduction in flow rate and heat transfer coefficient. The predicted milk deposit distribution on the plate surface is expected to determine the sensor location appropriate for on-line monitoring and furthermore, optimization of the thermal process for minimizing milk fouling.

An Experimental and Theoretical Investigation of the Effect of Flow Maldistribution on the Thermal Performance of Plate Heat Exchangers

An experimental and theoretical study of the effect of flow maldistribution from port to channel on the thermal performance of single and multipass plate heat exchangers is presented. In general, flow maldistribution brings about an increase in pressure drop and decrease of the thermal performance in heat exchangers. This deterioration is found to depend on flow rate, number of channels, and port size. Experiments show that analytical predictions of pressure drop and thermal performance in presence of flow maldistribution are quite accurate for practical purposes. The results indicate that under identical conditions, maldistribution is more severe in Z-type plate heat exchanger compared to U type. Multipassing is found to reduce the maldistribution effect significantly. An insight to the physical aspects of maldistribution and its possible reduction through proper design strategy are also presented.

Effect of Flow Distribution to the Channels on the Thermal Performance of the Multipass Plate Heat Exchangers

Over last two decades, plate heat exchangers (PHEs) have presented themselves as a viable alternative to the conventional shell and tube heat exchangers in the process and power industries. The thermal theory available for plate heat exchangers in the literature largely works on the assumption of equal flow in each channel. However, it is well known that the distribution of fluid from port to channel in PHE is far from being uniform. The present study brings about this port to channel flow distribution effect on the thermal behavior of multipass plate heat exchangers. The variation of the heat transfer coefficient due to flow variation from channel to channel has also been taken into consideration. Heat exchangers with both equal and unequal passes of the fluids have been studied. The results indicate that the flow maldistribution severely affects the performance of plate heat exchangers, and multipassing can act as an important tool to reduce the deterioration in performance due to maldistribution. The results show that with a low number of passes, the increase of velocity of fluid may be counterproductive in terms of heat transfer enhancement. Also, adding plates in order to increase the heat transfer surface may not be effective due to an increase in flow maldistribution. The correlations for 1-1, 1-2, 2-2, and 2-3 pass plate heat exchangers with the maldistribution index as a parameter are also presented.

A DYNAMIC 2D MODEL FOR THERMAL PERFORMANCE OF PLATE HEAT EXCHANGERS

A 2D dynamic model was developed to interpret the transient thermal performance of plate heat exchangers (PHEs) as a stepping stone toward better understanding of localized milk fouling phenomena. The conventional 1D model, which is used as a basis of most fouling models, was compared with the 2D model in two different types of multichannel PHEs. To measure the local temperatures of the fluid, T-type thermocouples, placed at 15 different locations on a plate, were inserted between the channels of interest. The 1D model, which is based on unidirectional, constant velocity flow, showed limited predictive accuracy for the experimental data and was dependent on the flow characteristics (i.e., an average 3.9% deviation for a fully developed flow scheme, and 36.1% deviation for a potential eddy flow scheme). On the other hand, the 2D model, which takes into account the hydrodynamics of the flow stream, was capable of predicting the temperature distribution of the fluid flow with an average 6.2% deviation, irrespective of the flow pattern. The validated 2D model is expected to enable better identification of potential regions of milk deposits when compared with the conventional 1D model.

General Model for Plate Heat Exchanger Performance Prediction

A general heat transfer and pressure drop model is presented for plate heat exchangers. For many years we noticed a strong advancement in the field of plate heat exchangers. These developments were due to new materials, manufacturing technology, and chevrons configurations, which make the heat exchanger more and more compact. But to determine the heat transfer and pressure drop performances, we still need empirical correlations established as a function of geometric parameters variations, like chevron angle, amplitude, and pitch. The new model presented in the paper, called the universal model, is based on the theory of porous media and includes the simultaneous influence of 11 geometric parameters of the plate. Two unique correlations for single-phase flow are proposed to simulate the heat transfer coefficients and friction factors as well as the global heat load and pressure drop for the wide range of Reynolds numbers. The comparison with many experimental results shows the accuracy of the model.