Minimum Pressure Drop Research Articles

Numerical investigation on the effect of flow field and landing to channel ratio on the performance of PEMFC

Three-dimensional numerical investigation of PEMFC with landing to channel ratio (L:C) of 2:2 for 25-cm2 serpentine-parallel channel has been simulated, and the obtained results have been validated with the polarization curve obtained through experiments. It is found that the maximum error in the polarization curve is less than 4%, and thus a very good deal exists between the simulation study and experimentation. Upon validation, the study has been extended for various flow path designs with different L:C ratio numerically. The prediction reveals that the L:C ratio of 2:2 exhibits the better performance for all the flow channels considered, and it is found that the straight-zigzag flow field with L:C ratio of 2:2 attributes the maximum power density of 0.3250 W/cm2 for an optimum open circuit voltage of 0.4 Volts with minimal pressure drop. Oxygen consumption in the cathode flow channels of serpentine-parallel, serpentine-zigzag, and straight-parallel are 77.08%, 10.41%, and 42.70% lesser than that of straight-zigzag PEMFC, respectively. The pressure drop in the flow channel of serpentine-parallel, serpentine-zigzag, and straight-parallel with landing to channel ratio 2:2 are 78.18%, 95.81%, and 48.33% higher than that of straight-zigzag flow field, respectively. The polarization curve, hydrogen (H2), oxygen (O2), water content along the flow channel and the proton conductivity, H2O content across the membrane electrolyte, and current density contour at the GDL/catalyst interface of the anode side for all flow channel configurations have been presented and discussed.

Experimental Investigation of Adiabatic Gas-Liquid Flow Regimes and Pressure Drop in Slit Microchannel

The flow regimes and pressure drop in a slit microchannel with a height of 164 μm and width of 10 mm are studied experimentally. The boundaries between the regimes are precisely determined using the developed procedure. The homogeneous flow model and the separated flow model are considered for determining the frictional pressure drop. Experimental data are compared with theoretical models. For the homogeneous flow model, the Dukler correlation gives good agreement with experimental data with a mean absolute error of 12%. A new correlation, which describes the experimental data with a mean absolute error of 8.1%, is proposed for the homogeneous flow model. For the separated flow model, the Hwang and Kim correlation gives the best agreement with a mean absolute error of 12.8%. The dependence of the pressure drop in the film flows (annular and stratified regimes) on the mass gas quality has been investigated. It is shown that the minimal pressure drop for the film flows is achieved in the stratified regime; thus, it is the most promising for the use in technical applications.

Performance optimiation of a cylindrical mini-channel heat sink using hybrid straight–wavy channel

The problem of high pressure drop remains a challenge in the design of heat sinks using the passive techniques of heat transfer enhancement. Wavy channels are widely used to improve the transfer of a mini-channel heat sink but with an undesirable pressure drop. A new channel design was proposed to enhance the performance of a cylindrical mini-channel heat sink (CMCHS) with a minimal possible pressure drop. The design was a straight–wavy hybrid channel, in which the channel path changes from straight at the entrance of the CMCHS to wavy. 3D computational fluid dynamics was performed to analye the fluid flow and heat transfer of the CMCHS. Simulation was conducted on the CMCHS water with a Reynolds number of less than 500. On the basis of entropy generation minimiation technique, CMCHS performance was optimied using different geometric parameters. The parameters included entrance channel length ratio and the wave amplitude ratios of the second and third sections of the channel. A test rig was manufactured to test CMCHSs for a wide range of operating conditions to validate the simulation model. Two models of CMCHS with straight and hybrid straight–wavy channels were developed on the basis of the optimum dimensions acquired from the numerical prediction. Results revealed that the overall performance of the CMCHS with a straight–wavy channel is better than that with a straight channel under the same operating conditions. The straight–wavy channel is more effective than the conventional straight channel in reducing the maximum surface temperature along the channel length of the CMCHS. The temperature uniformity along the CMCHS with a straight–wavy channel is better than that with a straight channel.

On the design of heat exchanger equipment for novel-type isobaric expansion engines

The recently proposed idea of displacer-type heat engines with dense working fluids revived the long-known concept of isobaric expansion (IE). Capable of overcoming some of the most severe disadvantages of gas-phase displacer-type heat engines and state-of-the art ORC plants, these engines offer a solution for future heat-to-power conversion and heat driven pumps or compressors. Effective heat regeneration and heat transfer in general are key issues of all types of displacer-type heat engines and thus, compact heat exchangers with minimum internal volume and pressure drop are required. This study is dedicated to the effects of regeneration on efficiency and considers efficiency-abating internal (dead) volumes and pressure drop. Printed Circuit Heat Exchangers (PCHE) are proposed for application in IE engines and a design procedure for these apparatuses is introduced. The results show that efficiencies close to the optimum can be obtained if the channel size is below 1 mm. Along with recently presented theoretical and experimental studies on such IE engines, this affirms the great potential of this heat conversion technology.

Rotating Gliding Arc: Innovative Source for VOC Remediation

The large-scale plasma treatment of waste gas in industrial or municipal conditions requires high efficiency of plasma conversion process at high processing speed, i.e., large volumetric flow. The integration of the plasma unit into existing systems puts demands on the pipe-system compatibility and minimal pressure drop due to adoption of plasma processing step. These conditions are met at the innovative rotating electrode gliding arc plasma unit described in this article. The system consists of propeller-shaped high voltage electrode inside grounded metallic tube. The design of HV electrode eliminates the pressure drop inside the air system, contrary the plasma unit itself is capable of driving the waste gas at volumetric flow up to 300 m3/hr for 20 cm pipe diameter. In the article the first results on pilot study of waste air treatment will be given for selected volatile organic compounds together with basic characteristic of the plasma unit used.

Experimental hydrodynamic and bed characteristics of co-current gas-liquid-solid three phase semifluidization with liquid as the continuous phase

In this study, hydrodynamic parameters such as minimum liquid phase fluidization velocity semifluidization velocity pressure drop and height of top packed bed formation of a co-current gas-liquid -solid multiphase semifluidized bed were studied using the liquid as the continuous phase and air as the dispersed phase. Air, water, and acrylic beads of various sizes were used to represent the gas, liquid, and solid phases, respectively. The experiments were conducted in a vertical perspex column. The liquid and gas was co-currently fed into the column with varying flow rate. The column has three sections comprising of gas-liquid release section, main section, and gas-liquid distributor section, respectively. The significant outcomes of this study are reduced minimum fluidization velocity ranging from 0.004 to 0.01 m/s and minimum semifluidization velocity of 0.032–0.006 m/s compared to reported high values. Maximum bed pressure drop was found to be 5.6 kPa. Empirical mathematical correlations that represent the hydrodynamic and bed characteristics were developed from the experimental data which are also a new aspect of this study. Model results fitted well to the experimental values and the values obtained are quite useful for the various industrial application.

Development of new finned tube heat exchanger: Innovative tube-bank design and thermohydraulic performance

Three-dimensional numerical simulations are successfully carried out on thermo-hydraulic characteristics of a new plain fin-and-elliptical tube (PFET) heat exchanger with innovative types of tube-banks, namely—a slotted elliptical tube-bank (SETB) (Case B and Case C) and a slotted annular elliptical tube-bank (SAETB) (Case D and Case E). The new PFET heat exchanger contains elliptical cross-sectioned tubes that create narrow slots oriented in the streamwise or/and spanwise direction. The investigation on the effects of different shape tube-banks on the air-side heat transfer and fluid flow characteristics in the new PFET heat exchanger was performed using the ANSYS CFX® package. The objectives of this investigation are to determine an optimal staggered tube-bank configuration for augmenting heat transfer rates with minimal pressure drop penalties, and compare the results against traditional non-slotted elliptical tube-bank heat exchangers. The averaged heat transfer rate of the SETB/SAETB heat exchanger is more than 15% greater than that of the traditional non-slotted elliptical tube heat exchanger. The overall performance evaluation criteria, estimated in terms of the area goodness factor and volume goodness factor for enhanced cases (SETBs/SAETBs), were higher than there found by a non-slotted elliptical tube-bank case. Overall, the computational results showed that the Case D causes an appreciable increase of the heat transfer rate without a pressure drop penalty.

Topology optimization of liquid-cooled microchannel heat sinks: An experimental and numerical study

Electronics cooling is always a critical challenge for its small profile and high heat flux. Various microchannel heat sinks have been proposed in literature to achieve reliable and energy efficient cooling effect. They are mainly different patterned fin shapes originated from researchers’ experience. In this paper, we present the process of designing liquid-cooled microchannel heat sink fin geometries based on a numerical method, topology optimization. The optimization model is developed to find designs that satisfy heat transfer requirement with low pressure drop penalty. It is implemented based on a derived accurate 2D model with minimizing pressure drop as objective and average junction temperature as a constraint. Parameter study for different velocities and junction temperature constraints is performed. The optimized structures are then post processed under geometry constraints and analyzed by 3D CFD simulation. Size optimization is implemented on conventional straight channel heat sinks, which serve as the benchmark cases. Moreover, an experimental test loop is built to validate the 3D simulation of topology optimized heat sinks and straight channel heat sinks. The performance comparison shows that the topology optimized heat sinks could save up to 50.9% pumping power under the same thermal performance requirement. Detailed CFD analysis is then engaged to examine their thermohydraulic characteristics and reveal the reasons for their superior performance.

A multi-objective optimization problem in mixed and natural convection for a vertical channel asymmetrically heated

This paper deals with a multi-objective topology optimization problem in an asymmetrically heated channel, based on both pressure drop minimization and heat transfer maximization. The problem is modeled by assuming steady-state laminar natural convection f low. The incompressible Navier-Stokes equations coupled with the convection-diffusion equation, under the Boussinesq approximation, are employed and are solved with the finite volume method. In this paper, we discuss some limits of classical pressure drop cost function for buoyancy driven flow and, we then propose two new expressions of objective functions: the first one takes into account work of pressure forces and contributes to the loss of mechanical power while the second one is related to thermal power and is linked to the maximization of heat exchanges. We use the adjoint method to compute the gradient of the cost functions. The topology optimization problem is first solved for a Richardson (Ri) number and Reynolds number (Re) set respectively to Ri ∈ {100,200,400} and Re = 400. All these configuration are investigated next in order to demonstrate the efficiency of the new expressions of cost functions. We compare two types of interpolation functions for both the design variable field and the effective diffusivity. Both interpolation techniques have pros and cons and give slightly the same results. We notice that we obtain less isolated solid elements with the sigmoid type interpolation functions.Then, we choose to work with the sigmoid and solve the topology optimization problem in case of pure natural convection, by setting Rayleigh number to {3×103,4×104,5×105}. In all considered cases, our algorithm succeeds to enhance one of the phenomenon modeled by the proposed cost functions without deteriorating the other one. The optimized design obtained suppresses any reversal flow at the exit of the channel. We also show that the thermal exchanges are improved by computing the Nusselt numbers and bulk temperature. We conclude that the new expressions of objective functions are well suited to deal with natural convection optimization problem in a vertical channel.

Effect of Different Zigzag Channel Shapes of PCHEs on Heat Transfer Performance of Supercritical LNG

The channels of a printed circuit heat exchanger (PCHE) can have different shapes, and the zigzag channel shape is one of the most widely used because of the relatively simple manufacturing process and low cost. However, the heat transfer enhancement of a zigzag channel is at the expense of increasing the pressure drop. In this paper, new channel shapes of a PCHE, i.e., a zigzag with an inserted straight channel and a zigzag channel with radian, were numerically investigated, with the aim of improving the heat transfer and reducing the pressure drop of supercritical LNG using the SST κ-ω model. The local and total pressure drop and heat transfer performance of supercritical LNG in a zigzag channel, zigzags with 1–5 mm inserted straight channels, and a zigzag channel with radian were analyzed by varying the mass flow rate from 1.83 × 10−4 to 5.49 × 10−4 kg/s. Performance evaluation criteria (PEC) were applied to compare the overall heat transfer performance of the zigzags with 1–5 mm inserted straight channels and a zigzag channel with radian to the zigzag channel of a PCHE. The maximum pressure drop for the zigzag channel was twice the minimum pressure drop for the zigzag channel with radian, while the convective heat transfer coefficient of the zigzag with a 4 mm inserted straight channel was higher, which was 1.2 times that of the zigzag channel with radian with the smallest convective heat transfer coefficient. The maximum value of the PEC with 1.099 occurred at a mass flow rate of 1.83 × 10−4 kg/s for the zigzag with a 4 mm inserted straight channel, while the minimum value of the PEC with 1.021 occurred at a mass flow rate of 5.49 × 10−4 kg/s for the zigzag with a 1 mm inserted straight channel. The zigzag with a 4 mm inserted straight channel had the best performance, as it had a higher PEC value at lower mass flow rates.

The optimum position of porous insert for a double-pipe heat exchanger based on entropy generation and thermal analysis

In the present paper, the first and second laws of thermodynamics are utilized to select the optimized position of porous insert to achieve maximum heat transfer and minimum pressure drop and entropy generation inside a double-pipe heat exchanger. Four different porous inserts configuration are considered in the heat exchanger, where the porous layers are placed at the core of the inner tube, wall of the inner tube, and inner or outer walls on outer tube for these cases. In addition, the effects of Darcy number and thermal conductivity of porous material on entropy generation, heat transfer enhancement and pressure drop penalty are investigated. The flow and heat transfer are modeled using Computational fluid dynamics. It was found that for outer tube of a double-pipe heat exchanger, placing the porous layer in the inner wall creates larger pressure drops. For inner tube, it is better to place the porous layer at the center, while for outer one, it is better to insert the porous layer at inner wall (interface wall) to achieve the higher values of heat transfer rate. Moreover, the thermal and viscous entropy generations are more pronounced for the cases, where the porous substrate is not located at the core of the heat exchanger.

Thermal-Hydraulic Performance and Optimization of Tube Ellipticity in a Plate Fin-And-Tube Heat Exchanger

The flow field inside the heat exchangers is associated with maximum heat transfer and minimum pressure drop. Designing a heat exchanger and employing various techniques to enhance its overall performance has been widely investigated and is still an active research. The application of elliptic tube is an effective alternative to circular tube which can reduce the pressure drop significantly. In this study, numerical simulation and optimization of variable tube ellipticity is studied. The three-dimensional numerical analysis and a multi-objective genetic algorithm (MOGA) with surrogate modeling are performed. Tubes in staggered arrangement in fin-and-tube heat exchanger are investigated for combination of various elliptic ratios and Reynolds numbers. Results show that increasing elliptic ratio increases the friction factor due to increased flow blocking area, however, the effect on the Colburn factor is not significant. Moreover, tube with lower elliptic ratio followed by higher elliptic ratio tube has better thermal-hydraulic performance. To achieve the best overall performance, the Pareto optimal strategy is adopted for which the computational fluid dynamics (CFD) results, artificial neural network (ANN), and MOGA are combined. The tubes elliptic ratio and Reynolds number are the design variables. The objective functions include Colburn factor (j) and friction factor (f). The CFD results are input into ANN model. Once the ANN is computed, it is then used to estimate the model responses as a function of inputs. The final trained ANN is used to drive the MOGA to obtain the Pareto optimal solution. The optimal values of these parameters are finally presented.

Configuration Optimization and Performance Comparison of STHX-DDB and STHX-SB by A Multi-Objective Genetic Algorithm

Based on the thermohydraulic calculation model verified in this study and Non-dominated Sorted Genetic Algorithm-II (NSGA-II), a multi-objective configuration optimization method is proposed, and the performances of shell-and-tube heat exchanger with disc-and-doughnut baffles (STHX-DDB) and shell-and-tube heat exchanger with segmental baffles (STHX-SB) are compared after optimization. The results show that, except in the high range of heat transfer capacity of 16.5–17 kW, the thermohydraulic performance of STHX-DDB is better. Tube bundle diameter, inside tube bundle diameter, number of baffles of STHX-DDB and tube bundle diameter, baffle cut, number of baffles of STHX-SB are chosen as design parameters, and heat transfer capacity maximization and shell-side pressure drop minimization are considered as common optimization objectives. Three optimal configurations are obtained for STHX-DDB and another three are obtained for STHX-SB. The optimal results show that all the six selected optimal configurations are better than the original configurations. For STHX-DDB and STHX-SB, compared with the original configurations, the heat transfer capacity of optimal configurations increases by 6.26% on average and 5.16%, respectively, while the shell-side pressure drop decreases by 44.33% and 19.16% on average, respectively. It indicates that the optimization method is valid and feasible and can provide a significant reference for shell-and-tube heat exchanger design.

A newly developed electrostatic enhanced pleated air filters towards the improvement of energy and filtration efficiency

The widely utilized high efficient particulate air filters (HEPA) lead to high building energy consumption. Indoor particle removal technology with minimal pressure drop is urgently needed for both air purification and energy conservation. Electrostatic enhanced air filter (EEAF) has potential to achieve high filtration efficiency and low energy consumption simultaneously. It uses external electric field to improve fabric filter performance without adding pressure drop. However, available researches utilized EEAF with flat filter in laboratory-scale study, which restricted engineering applications due to limited filtration area and high pressure drop. In order to improve EEAF, the present study developed electrostatic enhanced pleated air filters (EEPF). Experiments and mathematical model established in our previous study were adopted to investigate filtration performance of EEPF for fine particles (0.01–10 μm). Compared to EEAF with flat filter, EEPF saved 75% energy consumption and improved filtration efficiency up to 20%. Results show that filtration efficiency of EEPF was sensitive to duct velocity, applied voltage and filter type. Ozone mass generated by EEPF satisfied ASHRAE standards. The validated mathematical model was adopted to optimize pleat geometries of EEPF. Compared with HEPA, optimal EEPF had comparable filtration efficiency (>98%) and saved 70% energy consumption.

Real-Time Reservoir Balancing and Leak-Free Nonaqueous Cell Design for Flow Batteries

Benchtop-scale testing of redox flow batteries presents numerous operational challenges related to electrolyte imbalance, leakage, and chemical compatibility. Electrolyte imbalance creates a capacity-limiting reservoir and necessitates manual or automatic transfer of electrolyte between reservoirs to rebalance. Leakage of electrolyte in the cell, often at tubing connections or interfaces between the graphite plates, gaskets, and membrane, also reduces capacity and experimental repeatability. The testing of increasingly common nonaqueous electrolytes requires not only strict wetted material compatibility across a range of solvents but also greater resistance to leaks – the lower surface tensions of many organic solvents (vs. water) makes them more prone to leakage. The above issues are more easily dealt with in large-scale, permanent installations that do not have the benchtop-scale requirements of manual assembly/disassembly, modularity, and configurational simplicity. Additionally, benchtop flow batteries often use peristaltic pumps, a type of positive displacement pump which create large pressure and flowrate pulsations compared to the continuous output of centrifugal pumps commonly used in large scale systems. The use of individual peristaltic pumps for each side of the flow battery can create an electrolyte imbalance when an asymmetric pressure drop occurs across the cell, causing a Darcy flow of electrolyte through the membrane separator. Other aspects of the flow battery can exacerbate this imbalance, such as using porous separators which are more permissive to electrolyte crossover, or more viscous electrolytes which create higher pressure differentials in the hydraulic circuit at a given flowrate. A new pump control strategy for flow batteries is designed and implemented which controls the speed and flowrate of the pumps in real time in response to the reservoir levels, as shown in Figure 1. This control scheme maintains balanced electrolyte reservoirs by minimizing the average differential pressure across the membrane. Minimal pressure drops are achieved by effectively matching the pressures in each half-cell of the battery by adjusting each pump’s speed and flowrate independently, so that both pumps are operating at the same pressure on their respective fluid mechanical system curves. Additionally, a more leak-resistant cell gasket design shown in Figure 2 is developed, while maintaining chemical compatibility for nonaqueous systems. These two developments are employed in a long-term cycling experiment using a nonaqueous disproportionation electrolyte. Figure 1

Minimize pressure drop and maximize heat transfer coefficient by the new proposed multi-objective optimization/statistical model composed of “ANN + Genetic Algorithm” based on empirical data of CuO/paraffin nanofluid in a pipe

A new multi-objective optimization model composed of the artificial neural network (ANN) and the genetic algorithm (GA) methods based on the empirical thermo-physical characteristics of CuO/liquid paraffin nanofluid flow in a pipe is presented for the first time. It means a new optimization /statistical approach is achieved based on ANN together with GA; so that at first ANN is employed to predict the nanofluid thermo-physical properties and then the heat transfer coefficient and the pressure drop ratios of the nanofluid to the basefluid, are optimized as well as to minimize the pressure drop ratio and maximize the heat transfer coefficient ratio by using the multi-objective optimization approach of GA. The results of the multi-objective optimization via the GA show that the Pareto optimal front quantifies the trade-offs in satisfying the two fitness function of heat transfer coefficient and the pressure drop ratios.

Design and evaluation of a high-flowrate nanoparticle respiratory deposition (NRD) sampler

A high-flow (10 L/min) nanoparticle respiratory deposition (NRD) sampler was designed and evaluated to achieve reduced limits of quantification (LOQs) for metal nanoparticles. The high-flow NRD consists of an inlet, impactor stage, diffusion stage, and a final filter. An impactor stage with 12 nozzles was designed from theory to achieve a cut-off diameter of 300 nm at 50% particle collection efficiency (d50). Various depths of 37-mm-diameter polyurethane foam cylinders were tested for the diffusion stage to obtain a collection efficiency curve similar to the deposition of nanoparticles in the human respiratory tract, known as the nanoparticulate matter (NPM) criterion. The objective for the final filter was a collection efficiency of near 100% with minimal pressure drop. The collection efficiencies by size and pressure drops were measured for all NRD sampler components. The final design of the impactor stage nozzle achieved a d50 of 305 nm. The collection efficiency for the diffusion stage with a depth of 7 cm when adjusted for presence of the impactor was the closest to the NPM curve with a R2 value of 0.96 and d50 of 43 nm. Chemical analysis of the metal content for foam affirmed that the high-flow NRD sampler required less sampling time to meet metal LOQs than the 2.5 L/min NRD sampler. The final filter with a modified support pad had a collection efficiency near 100%. The overall pressure drop of the sampler of 8.5 kPa (34 in. H2O) could not be handled by commercial personal sampling pumps. Hence the high-flow NRD sampler can be used as an area sampler or without the final filter for collection of nanoparticles.

Liquid hydrogen line chilldown experiments at high Reynolds Numbers. Optimal chilldown methods

Future cryogenic propulsion systems will require efficient methods to chill down propellant tanks and transfer lines prior to transfer of precious propellant while in space. When chilling down the transfer line, there is an inherent tradeoff between propellant mass consumed and chilldown time to steady state. This paper proposes a parameter based on a simplified energy balance that can be used to compare the efficiency of different chilldown methods and to determine the optimal chilldown method. The parameter, along with chilldown time and mass, is then applied to recent liquid hydrogen (LH2) line chilldown experiments conducted at NASA Glenn to compare efficiencies between numerous trickle and pulse chilldown tests across a wide range of LH2 temperatures and mass flow rates. Secondary parameters such as heat transfer coefficient, minimum pressure drop, and number of valve cycles are also considered for completeness.

Heat transfer enhancement of internal laminar flows using additively manufactured static mixers

This paper investigates heat transfer enhancement by means of additively manufactured static mixers during liquid water cooling of a horizontal, heated flat plate. The static mixers disrupt the thermal boundary layer and induce mixing, resulting in an increased heat transfer rate of about 2X larger than flows without mixers. Simulations of the flows provided insights into the flows near the mixers, and guided selection of specific mixer geometries. The mixers were fabricated directly into the flow channels using additive manufacturing and then assembled onto the heated plate. Two types of mixing structures were analyzed: twisted tape structures that are similar to conventional static mixers; and novel chevron-shaped offset wing structures. Heat transfer performance was measured for liquid water (510 ≤ Re ≤ 1366) cooling the heated section with convective heat flux ranging between 0.1 and 0.8 W/cm2. This work demonstrates the potential of additive manufacturing to enable novel flow geometries that can enhance convection heat transfer whilst minimizing pressure drop penalties and volumes.

Experimental evaluation of nozzles to mitigate liquid loading in gas wells

An optimally designed nozzle can be used as an efficient artificial lift system to deliquify gas wells. The objective of this work is to determine the most optimum nozzle parameters and geometry that would maximize critical pressure ratio while minimizing pressure drop across the nozzle under two-phase flow conditions. Six optimum nozzle geometries, evaluated under single-phase flow conditions in a previous study, are evaluated in this work. Two separate facilities were used to conduct the two-phase (air and water) experiments: a horizontal facility with 1.5 in. inner diameter (ID) PVC pipelines and a 30 ft long lateral pipeline section, and a vertical facility with 1.5 in. ID PVC pipelines and a 30 ft long vertical pipeline section. The horizontal facility was used to study the effect of introducing water into the system as a second phase, and the vertical facility was used to simulate conditions of a gas well with a nozzle installed as an artificial lift system. Horizontal flow experimental results showed that critical pressure ratio decreases for two-phase flow relative to single-phase flow. The distance of the annular churn flow pattern observed downstream the nozzle may be related to the nozzle performance; significantly lower performance was observed for the LJ nozzle in two phase horizontal testing relative to other nozzles – one characteristic this might be attributed to is the peculiarly longer distance of downstream annular churn flow pattern observed for this particular nozzle compared to other nozzles. Based on data analysis, the ASTAR nozzle group showed the most improved performance, similar to results obtained in single-phase horizontal testing. Based on vertical experimental results, the most optimum nozzle geometry to deliquify a loaded gas well was identified as the ASTAR nozzle 2, a parabolic nozzle geometry. A significant temperature drop downstream the nozzle was observed during these experiments. It is important to account for temperature change while designing a nozzle in order to avoid flow assurance problems, such as gas hydrate formation. The trends observed in relative performance between different nozzle geometries (rankings based on critical pressure ratio and pressure drop) for two-phase vertical experiments were similar to those observed for single-phase horizontal experiments. Therefore, single-phase experiments could be sufficient to evaluate relative nozzle geometry performance based on critical pressure ratio, for the conditions used in this study.