Heat Exchanger Shellside Pressure Drop: Comparison of Predictions With Experimental Data

1988 ◽  
Vol 110 (1) ◽  
pp. 68-76 ◽  
Author(s):  
R. S. Kistler ◽  
J. M. Chenoweth

A unique set of heat exchanger shellside pressure drop experimental data has become available from experiments at Argonne National Laboratory as a part of an ongoing research program in flow-induced vibration. These data provide overall pressure drop for a number of typical industrial heat exchanger configurations in addition to incremental pressure drop measurements along the shellside path. The test program systematically varied the baffle spacing, the tubefield pattern, and nozzle size for a series of isothermal water tests for segmentally baffled bundles. Also recently a comprehensive method has been published in the Heat Exchanger Design Handbook (HEDH) for the prediction of bundle shellside pressure drops. A search of the literature failed to reveal a complementary method for predicting the shellside nozzle pressure losses. This paper compares the predicted with the measured data and validates the adequacy and limitations of the HEDH method for full bundles of plain tubes. It further applies an extension to the method for no-tubes-in-the-window bundles. Adjustments were indicated to improve the predictions for finned tubes and methods were developed to predict shellside nozzle pressure drops. Overall pressure drop predictions were within plus or minus 20 percent.

1988 ◽  
Vol 110 (1) ◽  
pp. 60-67 ◽  
Author(s):  
H. Halle ◽  
J. M. Chenoweth ◽  
M. W. Wambsganss

Throughout the life of a heat exchanger, a significant part of the operating cost arises from pumping the heat transfer fluids through and past the tubes. The pumping power requirement is continuous and depends directly upon the magnitude of the pressure losses. Thus, in order to select an optimum heat exchanger design, it is is as important to be able to predict pressure drop accurately as it is to predict heat transfer. This paper presents experimental measurements of the shellside pressure drop for 24 different segmentally baffled bundle configurations in a 0.6-m (24-in.) diameter by 3.7-m (12-ft) long shell with single inlet and outlet nozzles. Both plain and finned tubes, nominally 19-mm (0.75-in.) outside diameter, were arranged on equilateral triangular, square, rotated triangular, and rotated square tube layouts with a tube pitch-to-diameter ratio of 1.25. Isothermal water tests for a range of Reynolds numbers from 7000 to 100,000 were run to measure overall as well as incremental pressure drops across sections of the exchanger. The experimental results are given and correlated with a pressure drop versus flowrate relationship.


Author(s):  
Seok Ki Choi ◽  
Il Kon Choi ◽  
Kil Yong Lee ◽  
Ho Yun Nam ◽  
Jong Hyeun Choi ◽  
...  

An experimental study has been carried out to measure the pressure drop in a 271-pin fuel assembly of a liquid metal reactor. The rod pitch to rod diameter ratio (P/D) of the fuel assembly is 1.2 and the wire lead length to rod diameter ratio (H/D) is 24.84. Measurements are made for five different sections in a fuel assembly; inlet orifice, fuel assembly inlet, wire-wrapped fuel assembly, fuel assembly outlet and fuel assembly upper region. A series of water experiments have been conducted changing flow rate and water temperature. It is shown that the pressure drops in the inlet orifice and in the wire-wrapped fuel assembly are much larger than those in other regions. The measured pressure drop data in a wire-wrapped fuel assembly region is compared with the existing four correlations. It is shown that the correlation proposed by Cheng and Todreas fits the best with the present experimental data among the four correlations considered.


Author(s):  
Jian Song ◽  
Limin Liu ◽  
Simiao Tang ◽  
Yingwei Wu ◽  
Wenxi Tian ◽  
...  

Due to great deal of operation experience and technology accumulation, sodium cooled fast reactor (SFR) is the most promising among the six Generation IV reactors, which has advantages of breeding nuclear fuel, transmuting long-lived actinides and good safety characteristics. Thermal-hydraulic computer codes will have to be developed, verified, and validated to support the conceptual and final designs of new SFRs. However, work on developing thermal hydraulic analysis code for SFR is very limited in China, while the common software RELAP5 MOD3 is unable to analyze liquid metal systems. So the modified RELAP5 MOD3.2 is being considered as the thermal-hydraulic system code to support the development of the SFRs. The thermodynamic and transport properties of sodium liquid and vapor have been implemented into the RELAP5 MOD3.2 code, as well as the specific heat transfer correlations for liquid metal. The sodium liquid properties use polynomial equations based on data obtained from Argonne National Laboratory, and the vapor is assumed to be perfect gas. The property equations are acceptably accurate for analysis of SFR, especially for single-phase liquid. New files are added to the fluids directory to generate property tables for new working fluid, which are similar to the table interpolation subroutines for light and heavy water in the original file directory. The method of code modifications are universal for other working fluids and will not affect the code original performance. Some basic verification work for the modified code are carried out. The steam generator of CEFR is analyzed to verify the modified code. The calculated results show that all the water will boil off in the evaporator and the calculated results are in good agreement with the design values. By using modified RELAP5 to model the primary loop of EBR-II fast reactor, the SHRT-17 PLOF test was analyzed. The results show that the natural circulation can be established in the EBR-II primary system after main pumps off to remove the core decay residual heat effectively, and the peak temperature under the safety limits. Moreover, the results computed in this work compared well with the test experimental data for the steady state condition. During the transients, the changing trends of temperature and pressure are similar to experimental data. The discrepancies between calculation and experiment are considered acceptably which need to be improved in the future work. Our work could demonstrate the capability and reliability of the modified RELAP5 for the analysis of SFRs further.


Author(s):  
Xianliang Lei ◽  
Huixiong Li ◽  
Shuiqing Yu ◽  
Yifan Zhang ◽  
Tingkuan Chen

With the development of supercritical (and even ultra-supercritical) pressure boilers (SCBs) with high capacities, and at the same time, with the consideration of supercritical pressure water-cooled reactors (SCWRs) as one of the six most promising reactor concepts accepted in the Generation IV International Forum (GIF), flow and heat transfer of supercritical water becomes more and more important for both the design and operation safety of the related facilities. Thermo-hydraulic characteristics are among the issues, which are of special significance for the SCBs and SCWRs. It has been found that at supercritical pressures, the hydraulic resistance of water exhibits special characteristics in regions near its pseudo-critical point, which is hereafter called the minimum drag coefficient phenomenon. Experimental investigation was carried out in the present study to investigate further the characteristics of drag coefficient of supercritical pressure water under different conditions. The total pressure drop characteristic of water flowing in smooth tube and internally ribbed tube under the supercritical pressures was measured in experiments with a wide range of operational parameters, such as the system pressures ranging from 23 to 28 MPa, the average heat fluxes varied from 100 kW/m2 to 500kW/m2, and the mass fluxes of water in a range of 600 ∼ 1050 kg/m2s. The experimental data were compared with prediction results calculated by existing common correlations for single phase pressure drops, and large discrepancies were observed between the experimental data and the prediction results. Furthermore, the pressure drops characteristics of supercritical pressure water in cases with different tube arrangement and test conditions were compared with each other, such as that in horizontal tubes and vertical tubes, and that in isothermal flows and in non-isothermal flows. Additionally, this phenomenon observed in the present studies was also analyzed by using computational fluid dynamics technology, and the mechanism of pressure drop variation was reasonably explained. It was found that the deviation appeared between the previously proposed drag coefficient correlations and the present experimental data was mainly owning to ignoring the variation of an existence of the minimum drag coefficient in the pseudo critical region in previous studies, and based on the data obtained in this study, a new correlation for drag coefficient for supercritical pressure water was presented.


2004 ◽  
Vol 126 (5) ◽  
pp. 687-696 ◽  
Author(s):  
Jonathan A. Olivier ◽  
Leon Liebenberg ◽  
Mark A. Kedzierski ◽  
Josua P. Meyer

This paper presents a study of pressure drops during condensation inside a smooth, an 18-deg helical microfin, and a herringbone microfin tube. Measurements were conducted with refrigerant flowing through the tube of a concentric heat exchanger, with water flowing in a counterflow direction in the annulus. Each tube was part of a condenser consisting of eight subcondensers with instrumentation preceding each subcondenser. Three refrigerants were used, namely, R-22, R-407C, and R-134a, all operating at a saturation temperature of 40 °C with mass fluxes ranging from 400 to 800kg/m2 s. Inlet qualities ranged from 0.85 to 0.95 and outlet qualities ranged from 0.05 to 0.15. The test results showed that on average for the three refrigerants the pressure gradients of the herringbone microfin tube were about 79% higher than that of the smooth tube and about 27% higher than that of the helical microfin tube. Further, a correlation from the literature for predicting pressure drops inside a helical microfin tube was modified for the herringbone microfin tube. The modified correlation predicted the data to within an error of 1% and had an absolute mean deviation of 6.8%. This modified correlation compared well with a correlation from the literature that predicted the data to within an error of 7%.


2012 ◽  
Vol 29 (2) ◽  
pp. 115 ◽  
Author(s):  
N.Z Aung ◽  
T Yuwono

Nine existing mixture viscosity models were tested for predicting a two-phase pressure drop for oil-water flow and refrigerant (R.134a) flow. The predicted data calculated by using these mixture viscosity models were compared with experimental data. Predicted data from using one group of mixture viscosity models had a good agreement with the experimental data for oil-water two-phase flow. Another group of viscosity models was preferable for gas-liquid flow, but these models gave underestimated values with an error of about 50%. A new and more reliable mixture viscosity model was proposed for use in the prediction of pressure drop in gas-liquid two-phase flow.


Author(s):  
Pardeep Garg ◽  
Pramod Kumar ◽  
Pradip Dutta ◽  
Thomas Conboy ◽  
Clifford Ho

A supercritical CO2 test facility is currently being developed at Indian Institute of Science, Bangalore, India to analyze the performance of a closed loop Brayton cycle for concentrated solar power (CSP) generation. The loop has been designed for an external heat input of 20 kW, a pressure range of 75–135 bar, flow rate of 11 kg/min, and a maximum cycle temperature of 525 °C. The operation of the loop and the various parametric tests planned to be performed are discussed in this paper. The paper addresses various aspects of the loop design with emphasis on design of various components such as regenerator and expansion device. The regenerator design is critical due to sharp property variations in CO2 occurring during the heat exchange process between the hot and cold streams. Two types of heat exchanger configurations 1) tube-in-tube (TITHE) and 2) printed circuit heat exchanger (PCHE) are analyzed and compared. A PCHE is found to be ∼5 times compact compared to a TITHE for identical heat transfer and pressure drops. The expansion device is being custom designed to achieve the desired pressure drop for a range of operating temperatures. It is found that capillary of 5.5 mm inner diameter and ∼2 meter length is sufficient to achieve a pressure drop from 130 to 75 bar at a maximum cycle temperature of 525 °C.


2008 ◽  
Vol 130 (5) ◽  
Author(s):  
T. A. Jankowski ◽  
E. N. Schmierer ◽  
F. C. Prenger ◽  
S. P. Ashworth

A simple model is developed here to predict the pressure drop and discharge coefficient for incompressible flow through orifices with length-to-diameter ratio greater than zero (orifice tubes) over wide ranges of Reynolds number. The pressure drop for flow through orifice tubes is represented as two pressure drops in series; namely, a pressure drop for flow through a sharp-edged orifice in series with a pressure drop for developing flow in a straight length of tube. Both of these pressure drop terms are represented in the model using generally accepted correlations and experimental data for developing flows and sharp-edged orifice flow. We show agreement between this simple model and our numerical analysis of laminar orifice flow with length-to-diameter ratio up to 15 and for Reynolds number up to 150. Agreement is also shown between the series pressure drop representation and experimental data over wider ranges of Reynolds number. Not only is the present work useful as a design correlation for equipment relying on flow through orifice tubes but it helps to explain some of the difficulties that previous authors have encountered when comparing experimental observation and available theories.


Author(s):  
Mesbah G. Khan ◽  
Amir Fartaj

In past few years, narrow diameter flow passages (≤3 mm) have attracted huge research attentions due to their several advantageous features over conventional tubes (≥6 mm) especially from the view points of higher heat transfer, lesser weight, and smaller device size. Several classifications of narrow channels, based on sizes, are proposed in the open literature from mini to meso and micro (3 mm to 100 μm). The meso- and micro-channels have not yet entered into the HVAC and automotive heat exchanger industries to the expected potentials to take the above-mentioned advantages. The reasons may be the limited availability of experimental data on pressure drop and heat transfer and the lack of consolidated design correlations as compared to what is established for compact heat exchangers. While a number of studies available on standalone single straight channels, works on multi-channel slab similar to those used as typical thermal heat exchanger core elements are inadequate, especially the research on multichannel serpentine slab are limited in the open literature. The 50% ethylene glycol and water mixture is widely used in heat exchanger industry as a heat transfer fluid. Studies of pressure drop and heat transfer on this commercially important fluid using narrow tube multi-channel slab is scarce and the availability of experimental data is rare in the open literature. Conducting research on various shapes of meso- and micro-channel heat exchanger cores using a variety working fluids are a definite needs as recommended and consistently urged in ongoing research publications in this promising area. Under present long-term project, an automated dynamic single-phase experimental infrastructure has been developed to carryout the fluid flow and heat transfer research in meso- and micro-channel test specimens and prototype microchannel heat exchanger using a variety of working fluids in air-to-liquid crossflow orientation. In the series, experiments have been conducted on 50% ethylene glycol and water solution in a serpentine meso-channel slab having 68 individual channels of 1 mm hydraulic diameter to obtain the heat transfer data and the general pressure drop nature of the test fluid. Current paper presents the heat transfer characteristics of ethylene glycol-water mixture and the Reynolds number effects on pressure drop, heat transfer rate, test specimen NTU and effectiveness, overall thermal resistance, and the Nusselt number.


Author(s):  
Ting Xiong ◽  
Bo Wen ◽  
Yuanfeng Zan ◽  
Xiao Yan

In order to obtain the hydraulic resistance characteristics of steam generator (SG) tube support plates (TSP), experimental as well as CFD studies have been carried out on both the single-phase and two-phase hydraulic resistances of various trefoil or quatrefoil orifice plates. Results show that with the increase of the Renylod number, the single-phase pressure drop coefficient decreases firstly and remains almost constant later. The single-phase pressure drop coefficient decreases with the increase of the chamfer radius of orifice or flow area. The two-phase pressure drops predicted by the empirical correlations are generally larger than the experimental results, while the pressure drops predicted by CFD software agree with the experimental data.


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