Pressure Drop Correlations Research Articles

Condensation heat transfer and pressure drop of low GWP R-404A alternative refrigerants in a multiport tube

The literature survey reveals that condensation or evaporation studies on R-404A alternative refrigerants are very limited. Especially for the multiport tube, no prior investigation exists. In this study, four R-404A alternative refrigerants (GWP100≤2500: R-448A, R-449A and GWP100≤150: R-455A, R-454C) - including R-404A (GWP100 = 3922) were tested in a multiport tube having 0.80 mm hydraulic diameter. The tests were conducted changing the mass flux from 380 to 760 kg/m2s, vapor quality from 0.2 to 0.8. During the tests, the saturation temperature and the heat flux were maintained at 45 °C and at 6 kW/m2. The results showed that the heat transfer coefficients of the alternative refrigerants were higher than those of R-404A. The reason was attributed to the better thermo-physical properties of the alternative refrigerants. Especially, at a high mass flux of this study, the gas core and the liquid film became turbulent, which mitigated the malign effect of temperature glide by strong mixing. Hence, the alternative refrigerants yielded higher heat transfer coefficients than R-404A. Some correlations with mixture correction predicted the heat transfer coefficient reasonably well with RMSE of approximately 0.20. An interesting finding is that even better predictions (RMSE of 0.13) were obtained when the correlation was not mixture corrected. The pressure drops were generally in the reverse order to the value of vapor density. Pressure drops of alternative refrigerants were larger than those of R-404A. The pressure drop correlations generally underpredicted the data.

Development of a thermal-hydraulic analysis code for thermal sizing of once-through steam generators for SMR

A one-dimensional thermal-hydraulic analysis code was developed for the conceptual design and sizing of once-through steam generators (OTSGs) with application to small modular nuclear reactors. The OTSG in the model is represented by one characteristic double-tube heat exchanger with countercurrent flow. The secondary side of the OTSG is divided into subcooled liquid region, saturated two-phase mixture region, and superheated vapor region. Heat transfer and pressure drop correlations for each flow region were selected and implemented. To benchmark predictability of the developed computer code, the B&W OTSG whose design data is available in open literature was simulated. The results were compared both to the design data of the OTSG and to the analysis results obtained using a best-estimate thermal-hydraulic analysis code. The overall characteristics of the heat transfer area, pressure, and temperature distributions calculated with the developed code were in good agreement with the design data as well as the results from the best-estimate code. Lastly, a new concept of OTSG that incorporates feedwater circulation to reduce its volume for SMR application was simulated using the developed code. This demonstrates that the code can be used for design innovation and performance analysis of OTSGs.

Machine learning algorithms to predict flow boiling pressure drop in mini/micro-channels based on universal consolidated data

Two-phase flow in mini/micro-channels can meet the high heat dissipation requirements of many state-of-the-art cooling solutions. However, there is lack of accurate universal methods for predicting parameters like pressure drop in these configurations. Conventional ways of predicting pressure drop employ either Homogeneous Equilibrium Model (HEM) or semi-empirical correlations. This current study leverages the availability of data collected over the past few decades to build several machine learning models to demonstrate the efficacy and ease of building and deploying such models. A consolidated database of 2787 data points for flow boiling pressure drop in mini/micro-channels is amassed from 21 sources that includes 10 working fluid, reduced pressures of 0.0006 –0.7766, hydraulic diameters of 0.15–5.35 mm, mass velocities of 33.1 < G < 2738 kg/m 2 s, liquid-only Reynolds numbers of 14–27,658, superficial vapor Reynolds number of 75.58–199,453 and flow qualities of 0 and 1. This consolidated database is utilized to develop four machine learning based regression models viz., Artificial Neural Networks (ANN), KNN regression, Extreme Gradient Boosting (XGBoost) and Light GBM. Both input parameters and hyperparameters are optimized for the individual models. The models with dimensionless input parameters: Bd, Bo, Frf, Frfo, Frg, Frgo, Frtp, Prf, Prg, Peg, Pef, Ref, Refo, Reg, Rego, Reeq, Suf, Sug, Wef, Wefo, Weg, Wego,Wetp predict the test data for ANN model, XGBoost model, KNN model, and LightGBM model with MAEs of 9.58%, 10.38%, 13.52%, and 14.49%, respectively. The optimized machine-learning models performed better than highly reliable generalized pressure drop correlations plus showed good performance across individual datasets, flow regimes, and channel configurations.

Void fraction and pressure drop of hydrocarbon mixture during condensation in a helically coiled tube

A study was conducted to investigate the void fraction and pressure drop characteristics of methane/propane under different mass flux, saturation pressure and heat flux in a helically coiled tube, and the effects of distribution ratio (methane/propane) 50/50, 66/34 and 80/20 mole% were also analyzed. The friction pressure drop increased with the mass flux increased. Similarly, with the decrease of saturation pressure, friction pressure drops decreased. For a different distribution ratio, the friction pressure loss increases as the propane component increased in the mixture. Meanwhile, existing correlation models of different forms were used to evaluate the void fraction, and the Ahrens model provided the best accuracy with a MARD (mean absolute relative deviation) of 2.85%. In addition, the existing pressure drop correlations were used to compare with simulated data. Friedel correlation gave a well prediction for non-annular data with a MARD of 16.1%, while Cavallini correlation can well predict annular flow data with a MARD of 16.6%. Finally, considering the influence of flow regime transition, a new frictional pressure drop correlative was proposed, which can predict the data well with MARD of 5.4%.

Heat Transfer Enhancement in Subchannel Geometry of Pressurized Water Reactor Using Water-Based Yttrium Oxide Nanofluid

Simulation of Computational Fluid Dynamic is applied to present the thermal performance of water-based Yttrium oxide nanofluid in subchannel of pressurized water reactor (PWR) system. Thermal hydraulic aspect such as pressure drop and heat transfer are estimated in typical conditions of pressurized water with flow rates ranged (20×103≤Re≤80×103) using fresh water (0 %vol.) and different volume fraction of water-Yttrium oxide nanofluid (2 and 4% vol.) as coolant fluid. Results were obtained and compared with correlations of single-phase pressure drop and convective heat transfer for the case of fully developed turbulent flow. The addition of Yttrium oxide nanoparticles to the coolant fluid in pressurized water reactor led to increase in convective heat transfer coefficient and pressure drop. Increasing the nanoparticle volume fraction of (2 and 4% vol.) causing an increase in the average Nu by 3.46% and 7.61%, respectively. The CFD model established in ANSYS software was validated by comparing the pressure drop of CFD results with Blasius correlation and Nu with Ma¨ıga et al. correlation and gave a good agreement.

Heat Transfer Correlations for Star-Shaped Fins

Star-shaped fins are a newer type of fin for which correlations for heat transfer and pressure drop do not yet exist in the literature. Therefore, correlation equations for air-side heat transfer and pressure drop in a finned heat exchanger with star-shaped stainless-steel fins in staggered arrangement were developed in this work. To obtain these correlations, a numerical analysis of the basic heat exchanger geometry and another 21 variants of heat exchanger geometry was performed using computational fluid dynamics, and then the results of laboratory tests of a model of heat exchangers with star-shaped fins were used. In the numerical analysis, the fin pitch, the fin thickness, and the air velocity at the inlet to the heat exchanger were varied. The Nusselt (Nu) and Euler (Eu) numbers were determined for each variation analyzed. Initial correlations for Nu and Eu were derived using the least-squares deviation method. The correlation coefficients thus obtained were adjusted to agree with the results of the laboratory tests. The deviation of the final obtained correlation for Nu from the experimental test results was up to 10% in the range of Re &lt; 3500, whereas for higher values of Re, the deviation was less than 2%. The Eu correlation deviated from experimental results up to 19% in the range of Re &lt; 4000, whereas in the range of Re &gt; 5600, the deviation was less than 1%. The correlations were valid in the range 2000 &lt; Re &lt; 16,000.

Experimental Investigation on Adiabatic Two-Phase Frictional Pressure Drop of R1234ze(E) and R134a in a Horizontal Minichannel

Abstract R1234ze(E) has been created as an environmentally friendly substitution of R134a. An experimental investigation on adiabatic two-phase frictional pressure drop inside a 1.88 mm horizontal minichannel with R1234ze(E) and R134a was conducted. The saturation pressure and mass flux ranged within 0.6–0.9 MPa and 450–900 kg/(m2 s). Based on the 299 measured data points, the influences of various factors, including saturation pressure, mass flux, and the like, are examined detailedly. Larger mass flux brings about larger frictional pressure drop, and vapor quality performs the same function, but saturation pressure works inversely. The frictional pressure drops between R1234ze(E) and R134a present no significant differences. The experimental data are compared against 23 predictive models, among which the one from Xu and Fang (2013, “A New Correlation of Two-Phase Frictional Pressure Drop for Condensing Flow in Pipes,” Nucl. Eng. Des., 263, pp. 87–96) gives the best accuracy. In addition, a database including 3150 experimental adiabatic two-phase frictional pressure drop data points is derived from the current study and 29 published literature. Based on the database, the 23 models are assessed, and the most effective one is from Müller-Steinhagen and Heck (1986, “A Simple Friction Pressure Drop Correlation for Two-Phase Flow in Pipes,” Chem. Eng. Process., 20(6), pp. 297–308). This work can provide guidance for choosing appropriate two-phase frictional pressure drop models under adiabatic conditions.

Effect of Ambient Temperature Variation on Pressure Drop During Condensation in Long Inclined Tubes

Abstract Two-phase flow pressure drop during condensation of steam inside inclined tube heat exchangers was investigated over a wide range of ambient temperature. The ambient temperature changes from 3 to 45 °C, the steam mass flux varies from 3 to 18 kg/(m2 · s), vapor quality ranges from 0.51 to 0.86. 608 data points were experimentally obtained and compared with eight commonly used correlations from the available literatures. Frictional pressure drop increases with increasing temperature difference and fan speed. For the full experimental dataset, the best overall performing correlation was obtained by using the Wallis correlation (MAPE = 17.60%, NRMSE = 14.87%). For cold ambient temperatures, (Tamb &amp;lt; 20 °C, N = 298), the best overall performing correlation was obtained by using the Carey correlation (MAPE = 11.02%, NRMSE = 14.71%). For hot ambient temperatures (Tamb &amp;gt; 30 °C, N = 196), the Lockhart and Martinelli correlation has shown the best performance (MAPE = 16.84%, NRMSE = 20.45%). An improved two-phase frictional pressure drop correlation based on the Wallis correlation (Wallis, 1969, One Dimensional Two-Phase Flow, McGraw-Hill, New York) is proposed.

Experimental and Pore-scale Analysis of Flow and Thermal Fields in a Packed Bed Channel

ABSTRACT The study investigates experimentally and numerically the problem of turbulent convective heat transfer and pressure drop in a packed bed with internal heat generation. The main objective is to develop correlations for the heat transfer between the bed and coolant as well as the pressure drop in the system using detailed experimental and 3-dimensional pore-scale numerical simulation. The system analysed is a horizontal circular channel filled with different stainless steel spheres with diameters of 5.5 mm, 6.5 mm and 7.5 mm. Dry air is used as working fluid. The study is performed for turbulent flow regimes with different Reynolds number (based on the spheres diameter) in the range of 900-2600. The spheres are heated using an electromagnetic induction heating method. Based on the experimental data, empirical correlations for turbulent pressure drop and convective heat transfer coefficient are developed. Results of pore-scale analysis show the complexity of the flow domain, which the velocity experiences a considerable increase compared to inlet velocity and is more evident in narrow gaps between spheres. Moreover, numerical results indicate the coupling of temperature and velocity fields, which a non-uniform velocity filed leads to non-uniform temperature distributions of air and solid spheres in the packed bed.

Heat transfer and pressure drop of refrigerant flow boiling in metal foam filled tubes with different wettability

Surface wettability has a significant effect on the flow boiling heat transfer coefficient in metal foam filled tubes. In the present study, the flow boiling characteristics of metal foam filled tubes with different wettability were experimentally investigated, covering the surface wettability of uncoated, hydrophobic and hydrophilic surfaces. The results showed that, for the hydrophilic metal foam filled tubes, the heat transfer coefficient and pressure drop are decreased by 2%–18% and 4%–15%, respectively than those for the uncoated ones; for the hydrophobic metal foam filled tubes, both the heat transfer coefficient and pressure drop are larger than those for uncoated ones, and the increments in the heat transfer and pressure drop are 6%–30% and 8%–35%, respectively. Based on the experimental data, the correlations for heat transfer and pressure drop of flow boiling in metal foam filled tubes with different wettability were developed with the deviations of ±6.4% and ±9.7%, respectively.

Review and a Theoretical Approach on Pressure Drop Correlations of Flow through Open-Cell Metal Foam

Due to their high porosity, high stiffness, light weight, large surface area-to-volume ratio, and excellent thermal properties, open-cell metal foams have been applied in a wide range of sectors and industries, including the energy, transportation, aviation, biomedical, and defense industries. Understanding the flow characteristics and pressure drop of the fluid flow in open-cell metal foams is critical for applying such materials in these scenarios. However, the state-of-the-art pressure drop correlations for open-cell foams show large deviations from experimental data. In this paper, the fundamental governing equations of fluid flow through open-cell metal foams and the determination of different foam geometry structures are first presented. A variety of published models for predicting the pressure drop through open-cell metal foams are then summarized and validated against experimental data. Finally, two empirical correlations of permeability are developed and recommended based on the model of Calmidi. Moreover, Calmidi’s model is proposed to calculate the Forchheimer coefficient. These three equations together allow calculating the pressure drop through open-cell metal foam as a function of porosity and pore diameter (or strut diameter) in a wide range of porosities ε = 85.7–97.8% and pore densities of 10–100 PPI. The findings of this study greatly advance our understanding of the flow characteristics through open-cell metal foam and provide important guidance for the design of open-cell metal foam materials for different engineering applications.

On instantaneous pressure surges and time averaged pressure drop in intermittent regime of two-phase flow

Vigorous aeration and instantaneous pressure fluctuations associated with intermittent flow cause severe erosion-corrosion in the piping systems which lead to material degradation or wall thinning and leakages. Sometimes, this phenomenon results in catastrophic failures and hazards in transportation pipelines for industries such as petroleum, nuclear, geothermal and chemical. Present analysis is on the instantaneous pressure surges associated with the intermittent flow patterns and the two-phase frictional pressure drop. Experiments are carried out for three distinct sub-regimes of intermittent flow namely; Plug, Less Aerated Slug (LAS) and Highly Aerated Slug (HAS) flow. Instantaneous pressure fluctuation and time averaged pressure drop along the pipe length are reported for 350 combinations of inlet flow conditions (in term of ReSL and ReSG) of intermittent flow regime. Combined images of captured visual observations and measured instantaneous pressure fluctuations are demonstrated in terms of their influence on erosion and corrosion in detail. The obtained results are compared with the existing models for estimation of two-phase pressure drop proposed by earlier researchers. Large deviations between the experimental results and existing pressure models signify the need of separate correlation for two-phase frictional pressure drop for intermittent flow regime. In this direction, a unified correlation for prediction of two-phase frictional pressure drop for intermittent flow regime is proposed. The measured experimental results and obtained correlation for pressure drop will help in avoiding the erosion-corrosion in piping system. Also, database presented in this paper will aid to the effective and safe design of piping systems for petroleum, nuclear, geothermal and chemical industries.

Effect of element thickness on the pressure drop in the Kenics static mixer

The prediction of pressure drop is critical to continuous manufacturing of pharmaceuticals and fine chemicals. Although many correlations have been developed to predict the pressure drop in static mixers, the effect of element thickness on the pressure drop has been surprisingly ignored. With the wide application of the milli-scale static mixer in continuous manufacturing, the element thickness of the static mixer appears to be a particularly prominent factor in the pressure drop. In this study, we define the free cross-sectional area ratio to consider how the element thickness affects the pressure drop in the Kenics static mixer. The partial least squares regression (PLSR) method combined with Latin hypercube sampling (LHS) is proposed to construct a new pressure drop correlation, which builds a relationship between the Reynolds number (Re), the aspect ratio (AR), the element thickness and the friction factor. The reliability of the proposed correlation was validated by the experimental results and showed a good prediction accuracy.

Numerical modeling of an outdoor unit heat exchanger for residential heat pump systems with nonuniform airflow and refrigerant distribution

Multirow finned tube heat exchangers have been extensively used as an outdoor unit in heat pump applications. Several factors, including nonuniform airflow distribution, refrigerant circuitry arrangement, fin and tube configurations, and operating conditions, have a significant influence on its thermohydraulic performance. For accurate outdoor unit heat exchanger modeling and analysis, developing a robust and experimentally validated numerical model reflecting the influence of realistic nonuniform airflow and refrigerant distribution is necessary. This paper presents a general-purpose numerical model, implemented in MATLAB, for a multirow finned tube heat exchanger using a tube-by-tube modeling approach based on the log mean enthalpy difference method. State-of-the-art heat transfer and pressure drop correlations are used for each refrigerant-side's flow regime and airside fin configuration. An alternative iteration loop is also incorporated to solve the complex circuitry of the heat exchanger under wet conditions. Simulation results of the current model yield consistent and more real heat transfer, pressure drop, and temperature contours using nonuniform airflow velocity profiles than those of the simplified models that assumed uniform airflow. Therefore, higher accuracy of the performance evaluation for complex refrigerant circuitry was achieved. Furthermore, current model is able to identify the exit vapor quality that allows proper selection of tubes and mass flow rates to avoid unnecessary superheat or sub cooling. The model is also validated with available experimental data, and the maximum error is within ±10.0%.

Correlations for Concentration Polarization and Pressure Drop in Spacer-Filled RO Membrane Modules Based on CFD Simulations.

Empirical correlations for mass transfer coefficient and friction factor are often used in process models for reverse osmosis (RO) membrane systems. These usually involve four dimensionless groups, namely Reynolds number (Re), Sherwood number (Sh), friction factor (f), and Schmidt number (Sc), with the associated coefficients and exponents being obtained by fitting to experimental data. However, the range of geometric and operating conditions covered by the experiments is often limited. In this study, new dimensionless correlations for concentration polarization (CP) modulus and friction factor are presented, which are obtained by dimensional analysis and using simulation data from computational fluid dynamics (CFD). Two-dimensional CFD simulations are performed on three configurations of spacer-filled channels with 76 combinations of operating and geometric conditions for each configuration, covering a broad range of conditions encountered in RO membrane systems. Results obtained with the new correlations are compared with those from existing correlations in the literature. There is good consistency in the predicted CP with mean discrepancies less than 6%, but larger discrepancies for pressure gradient are found among the various friction factor correlations. Furthermore, the new correlations are implemented in a process model with six spiral wound modules in series and the predicted recovery, pressure drop, and specific energy consumption are compared with a reference case obtained by ROSA (Reverse Osmosis System Analysis, The Dow Chemical Company). Differences in predicted recovery and pressure drop are up to 5% and 83%, respectively, highlighting the need for careful selection of correlations when using predictive models in process design. Compared to existing mass transfer correlations, a distinct advantage of our correlations for CP modulus is that they can be directly used to estimate the impact of permeate flux on CP at a membrane surface without having to resort to the film theory.

Application of a drop breakage model using the full energy spectrum and a specific realisation of turbulence anisotropy

An anisotropic drop breakage model is applied to CFD–PBM simulations of turbulent emulsification in a high–pressure homogeniser. We compare the exponent of Sauter mean diameter – pressure drop correlations with published experimental results and with exponents obtained using existing drop breakage models. Its theoretical value assuming homogeneous isotropic turbulence is -0.6, while experiments have shown exponents of smaller magnitude. A breakage frequency model using the full spectrum of isotropic turbulence is found to produce a value of the exponent near -0.6. Our newly developed anisotropic breakage model predicts an exponent of smaller magnitude, closer to experiments. Breakage frequency based on isotropic turbulence exhibits non–monotonic behaviour (by predicting a maximum value for a certain drop size); the effect of turbulence anisotropy is to reduce non–monotonicity. It is shown that this reduction in non–monotonicity drives the decrease in the magnitude of the exponent.

Prediction of steady-state two-phase flow of nitrogen + extinguishant in the pipeline and a correlation for mass flow rate

Nitrogen used for pressurization of a fire extinguisher could be partially dissolved in the fire extinguishing agent, forming a binary mixture accompanied by a phase change while flowing inside the pipeline. Notwithstanding the widespread use of fire extinguishing system, few effective methods have been considered to predict two-phase flow performance of nitrogen + extinguishant in the pipeline. This paper presents the study on the performance of the steady-state two-phase flow of extinguishant in the pipeline, including C3HF7 (HFC227ea), CF3I, and C2HF5 (HFC125). The average viscosity of mixture was calculated using six quoted methods (VM-1–VM-6). The corresponding prediction models (STFM-1–STFM-6) for large mass flux nitrogen + extinguishant in a fire extinguishing pipeline were developed based on the VM-1–VM-6. In comparison with previous experimental and theoretical data, the applicability and accuracy of the proposed mathematical models was examined from mass flow rate and pressure drop. The results indicated that both models STFM-2 and STFM-3 could accurately predict for mass flow rate and that STFM-2 could predict for pressure drop. Finally, new correlations for mass flow rate and pressure drop have been established accurately based on the predicted data, respectively. This work contributes to a good theoretical approach on the analysis of two-phase flow of nitrogen + extinguishant.

Integrated mathematical modelling of a 105 t/h biomass fired industrial watertube boiler system with varying fuel moisture content

In this paper, a steady-state 1D computer model of a complete sugarcane bagasse-fired boiler system is presented, which pays special attention to the different heat transfer phenomena encountered in the boiler heat exchangers. The model solves the mass, momentum and energy balance equations for water, flue gas and air streams in an integrated manner which utilizes fundamental equations and empirical correlations for pressure drop, radiative heat transfer and convection. The integrated model is successfully applied to model a 105 t/h industrial watertube boiler at three different load cases namely 100 t/h, 65 t/h and 35 t/h. The model results are validated using typical plant measurements. The mean relative predicted gas temperature errors are 1.47%, 0.58% and 4.84% respectively for the different load cases simulated, and for the water circuit temperature predictions the mean errors are 1.48%, 0.85% and 5.31% respectively. Additionally, a sensitivity analysis is performed on the integrated model, which investigates the influence of selected modelling parameters such as flame height on key boiler output variables such as the furnace exit gas temperature.

Multi-modality Functional Aortic Valve Phantom for Haemodynamic Assessment

Objective: Aortic stenosis (AS) is a prevalent valve condition with poor outcomes when left untreated. AS severity metrics are discordant in 30% of cases rendering clinical decision-making complex. Superior imaging techniques for non-invasive pressure estimation are emerging but progress is limited by access to invasive haemodynamic data. Our aim was to develop and test a magnetic resonance (MRI)- and ultrasound (US)-compatible valve phantom which could approximate in vivo haemodynamics and yield a reproducible ground-truth pressure measurement. Methods: Silicone 0030 was injected into 3D-printed moulds to create an aortic valve model. The valve was affixed into a rigid ring mount and placed within a silicone “aorta” which was suspended in an acrylic box and submerged in 1% agar compound. Pressure sensors were embedded along the “aorta” wall. The complete phantom was connected to a MRI-compatible pump. Imaging was undertaken using both US and MRI. A protocol which involved recurrent data acquisition under both constant and pulsatile flow was repeated for several different scenarios of dismantling and reassembling the phantom to assess reproducibility. Results: Geometry and function captured by either MRI or US imaging were anatomically and physiologically adequate, with accurate pressure trace morphology. Under different flow conditions the peak instantaneous pressure drops were well correlated amongst repeated measurements across scenarios (Table). Conclusions: Here we report successful creation and testing of a MRI and US compatible valve phantom with compliant aorta model and direct pressure measurement which achieves consistency and reproducibility to underpin further research into imaging-based characterization of AS. Pressure drop correlation Condition Valve Purge and refill Dismantle and remove valve Change valve 1 2 3 4 1 A no no no / .993 .991 .934 2 A yes no no .993 / .998 .967 3 A yes yes no .991 .998 / .961 4 B yes yes yes .934 .967 .961 /

Pressure drop in a prototypical 3D magnetohydrodynamic flow across contraction of a fusion blanket manifold

ABSTRACT Predicting 3D magnetohydrodynamic (MHD) pressure losses associated with liquid metal flows in complex geometry ducts is required to design breeding blankets for fusion reactors. Of such components, manifolds exhibit major pressure losses. Recent correlations [T. Rhodeset al. Magnetohydrodynamic pressure drop and flow balancing of liquid metal flow in a prototypic fusion blanket manifold. Phys. Fluids. 2018; 30: 057101.] demonstrate promise for predicting pressure drops in electrically insulated inlet manifolds. In the present work, the extend to which these correlations can be applied to outlet manifolds, which feature sudden contractions, is investigated in both viscous-electromagnetic (VE) and inertial-electromagnetic (IE) regimes for Reynolds numbers 50 < Re < 1500, Hartmann numbers 2500 < Ha < 5475, and expansion/contraction ratio 10. Numerical computations have shown that the MHD pressure drops in the eutectic lead-lithium (PbLi) flows in contractions are almost identical to those in the flows featuring expansion with slightly higher magnitudes in the contraction cases. The small discrepancy in the MHD pressure drop between contractions and expansions (<8%) suggests that the earlier obtained correlations for the 3D MHD pressure drop in a duct flow with a sudden expansion can also be applied to flows with a sudden contraction.