Uncertainty Of Flow Measurement Research Articles

A case study of canal seepage quantification using gain/loss method and electrical resistivity tomography in an intensively managed water resource system in the Treasure Valley, Idaho, United States

Monitoring groundwater-surface water (GW-SW) interactions is essential for effectively managing the available water resources in semi-arid and arid environments. The focus of this study was to quantify how much SW is being exchanged with the shallow GW aquifer in the Treasure Valley (TV), Idaho, USA. Previous water budgets estimated regional canal seepage without incorporating canal variability and flow measurement uncertainty. To address this, we applied both direct (gain/loss) and indirect (electrical resistivity tomography (ERT)) techniques. Direct seepage measurements were taken on canals capturing a range of different characteristics in the TV. The discrete measurements were then used to estimate the total seepage anticipated to be lost from these canals during the irrigation season. Our findings showed high seepage variability across the canals. The ERT inversion approach was utilized before and after the irrigation season by applying an advanced inversion scheme to better constrain the canal seepage spatial variability and uncertainty by quantifying changes in the saturated zone with 2D-ERT results. Temporal changes in the subsurface resistivity were observed due to the lateral flow from the nearby surface canal during the irrigation season. The combination of these approaches improves our understanding of SW-GW interactions in intensively managed irrigation systems.

Assessment of alternative fluid calibration to estimate traceable liquefied hydrogen flow measurement uncertainty

The usage of liquefied hydrogen (LH2) is growing fast as the EU aims to be climate-neutral by 2050. Therefore, reliable and consistent measurements of LH2 amounts (as determined by flow meters) will become increasingly important for custody transfers. Reliability and consistency of measurements is established from calibration. Due to the lack of facilities being able to calibrate flow meters directly with LH2 as calibration fluid, the question arises whether the measurement error of the calibration performed on a different fluid and different process conditions are representative for the errors when measuring LH2. An on-site calibration of two turbine meters measuring LH2 flow was performed. A Coriolis mass flow meter calibrated on water was used as a reference in conjunction with a dedicated flow meter model, which was validated by a directly SI-traceable calibration on liquefied natural gas. LH2 flow rates were within 1000 kg/h and 3000 kg/h, which are relevant to hydrogen transport by LH2 trailers. The analysis of the measurement data reveal errors on totalized mass ranging from 2.0 % to 2.9 % with a total calibration uncertainty of 1.3 % (k=2), where the main uncertainty source was identified as the on-site density estimate necessary to convert the volume flow measurements into mass flow measurements. The results indicate the need for reliable and accurate temperature measurements (the latter allowing for an accurate density estimate), so that volume based and mass based amount measurements can be compared with smaller uncertainties.

Testing transpiration rates of juvenile Aleppo pine trees using the heat ratio method under laboratory conditions

AbstractTree transpiration considerably contributes to evaporative fluxes to the atmosphere in terrestrial ecosystems. Accurate transpiration quantification provides relevant information about forest water use and may benefit adaptive forest management, especially in a global change context. Tree transpiration can be measured by several methods, and sap flow measurements are one of the most valued. However, species‐specific validations of these techniques are required to avoid undesirable bias. This is especially relevant in species with low transpiration rates where errors may be relevant, such as Aleppo pine trees (Pinus halepensis Mill.). Moreover, another significant source of uncertainty in sap flow measurements is probe misalignment. Hence, the aim of this study was to correlate transpiration rates estimated by sap flow probes using the heat ratio method (THRM) and load cells to independently monitor water transpiration in juvenile Aleppo pine trees. The corrections to improve transpiration measures, including misalignment correction, were applied to THRM results to test if the accuracy of results improved. These measurements were recorded in greenhouse under controlled conditions to implement different environmental conditions. The environmental variables that ruled the experiment, mainly vapour pressure deficit and soil water availability, spanned in a wide range of values. The results showed an accurate linear correspondence between TOBS and THRM for low and medium values, but moderate underestimations at high transpiration rates were observed. These underestimations were partly removed when applying probe misalignment correction. This study supports the notion that HRM offers accurate Aleppo pine transpiration estimations with low and medium values under a variety of abiotic conditions, which also has implications for HRM application in other isohydric species. The results also support the interest in the use of probe misalignment correction to estimate transpiration, mainly when high transpiration values are recorded. The results of this study can be considered as a preliminary approach for future research in order to improve the estimates of the transpiration rates of the Aleppo pine under the limiting conditions of the Mediterranean.

Data-driven model-based flow measurement uncertainty quantification for building central cooling systems using a probabilistic approach

Uncertainties inevitably exist in measurements and may lead to biases in making management and control decisions, and thus affect the energy performance of building central cooling systems. Water flow meters are essential for the monitoring and operational control of building central cooling systems, but they often suffer from significant measurement uncertainties due to site constraints and unfavorable working environment. An effective method to quantify the flow measurement uncertainties is urgently needed. This study proposes a data-driven model-based flow measurement uncertainty quantification strategy using Bayesian inference and Markov chain Monte Carlo sampling methods. The proposed strategy is tested and validated systematically on an air-cooled chiller. Four case studies with different levels of flow measurement uncertainties are conducted. The test results show that both systematic and random uncertainties of flow measurements are quantified accurately by this strategy. The 95% Bayesian credible intervals of systematic and random uncertainties contain their pre-set (actual) values, and their posterior means (estimated values) are very close to their pre-set values. The relative errors in quantifying flow measurement uncertainties are within 10%. The performance of the proposed method is quite satisfactory. This study provides a cost-effective and promising alternative for on-site flow meter calibration in engineering practice.

Highly accurate differential pressure FBG gas flow sensor

In this paper, the limitations of traditional electronic-type gas flow sensors for flow measurements in practical engineering applications such as flammable and explosive gas environments are discussed. Further, the importance and uncertainty of gas flow measurements in critical parts of industrial equipment are also discussed. In this work, a high-precision differential-pressure FBG gas flow and a temperature sensor with an embedded nozzle were designed using a long-diameter nozzle-type throttle tube with a fiber optic Bragg grating and an elastic-sensitive diaphragm composite strain mechanism. It was observed that the pressure difference between the two sides of the nozzle leads to the deformation of the elastic-sensitive diaphragm, and it results in a wavelength drift of the strain grating that is attached to the elastic diaphragm. Further, it also enables real-time monitoring of the gas flow value. Moreover, the temperature compensation grating which was attached to the side wall of the gas chamber was used to eliminate the cross-sensitivity of the strain grating as well as to improve measurement accuracy while implementing a temperature monitoring system. The experimental results showed that the Bragg wavelength drift in the fiber grating gas flow sensor acts as a quadratic curve with respect to the gas flow, and the experimental results were found to be highly compatible with the results of the theoretical analysis.

Efficiency Measurement and Modeling of a High‐Performance Mg2(Si,Sn)‐Based Thermoelectric Generator

Mg2(Si,Sn) is an attractive material class due to its excellent thermoelectric (TE) properties, its eco‐friendly constituents, its low mass density, and its low price. A lot of research has been done on optimizing its TE properties; however, works on its use in thermoelectric generators (TEG) are scarce. Herein, the first conversion efficiency measurement of a functional, fully Mg2(Si,Sn)‐based TEG, approaching a maximum value of 4% for an applied = 375 °C, is shown. A maximum power density of 0.9 W cm−2 (related to the cross‐sectional area of the TE legs) at =375 °C is also reported, which is among the highest performance of silicide‐based modules reported in literature. Efficiency measurements can be tricky due to the uncertainty of heat flow measurement and parasitic heat losses; therefore, assessing the measurement reliability by confronting it to theoretical calculations is necessary. TEG device simulation in a constant property model is used to compare measured data to expected values and a good match is found (<1% deviation for current at maximum power, <4% difference for maximum power output, deviation within measurement uncertainty range for heat flows and efficiency). The significant discrepancy between measurement and calculations of the inner electrical resistance reveals room for improvement. Cracks form due to thermally induced mechanical stress, which dramatically increase the inner electrical resistance. It is shown that by avoiding those cracks, the maximum power output and conversion efficiency of the TEG could be improved by 30%.

An online robust sequencing control strategy for identical chillers using a probabilistic approach concerning flow measurement uncertainties

Chiller sequencing control is crucial to the reliable and energy-efficient operation of multiple-chiller plants. It should not only ensure an adequate supply of cooling capacity for buildings, but also make the chillers work efficiently. The measurement uncertainties cannot be avoided and have significant negative effects on the chiller sequencing control. To cope with the challenges and uncertainties, this study proposed an online robust sequencing control strategy using a probabilistic approach for chiller plants under low-quality and uncertain flow measurements. An uncertainty processing model of flow measurements was developed based on the Bayesian inference and Markov chain Monte Carlo methods and an energy balance model. As the core of the proposed control strategy, the uncertainty processing model can quantify the measurement uncertainties of water flow rates accurately. According to the probability analysis, an online decision-making scheme was designed, and the risks in the online decision-making processes were assessed. Compared with the conventional chiller sequencing control strategies, the proposed control strategy could reduce the impacts of flow measurement uncertainties significantly. The results of case studies showed that the root-mean-square error of cooling loads was reduced significantly by about 79%, the total switching number of chillers was reduced by up to 35.71% under the positive flow measurement uncertainties, and the cumulative unmet cooling load was reduced by up to 31.22% under the negative flow measurement uncertainties. The proposed chiller sequencing control strategy is able to tolerate flow measurement uncertainties.

The Resulting Effect of Flow Pulsations on Calibration Constant of Acoustic Path in Ultrasonic Flowmeters.

The present paper compares, for the first time, the regimes of a pulsating turbulent flow in a smooth pipe in terms of 0.001 ≤ ω+ ≤ 0.0346 and 0.16 ≤ β ≤ 0.63 at Re ≈ 7000 with the uncertainty in estimating the flow rate by an ultrasonic flowmeter. It was revealed that the classification of pulsating flow regimes according to the dimensionless angular frequency ω+ does not have a direct relation with the K parameter equal to the ratio of the phase-average calibration constant in pulsating flow to the corresponding value in steady flow. The results of data processing showed that K depends on the relative amplitude of pulsations β and the position of the chord of the ultrasonic beam trajectory (L/R is distance L from the pipe center to the chord to the pipe radius R). In the coordinates β and L/R, there is a rather wide area where the uncertainty in flow rate estimation of pulsating flows should not exceed 0.5%. An increase in β or L/R leads to an increase in measurement uncertainty, which in the limiting case β, L/R → 1 can reach 5% or more. Favorable and unfavorable areas of the pipe section were identified when scanning pulsating flows and the effectiveness of using multi-path scanning schemes was estimated to reduce the resulting effect of flow pulsations on flow measurement uncertainty.

Flow measurement uncertainty quantification for building central cooling systems with multiple water-cooled chillers using a Bayesian approach

Measurement uncertainty has significant negative impacts on the operation and control of heating, ventilation and air conditioning systems. It is a big challenge and should be solved urgently. Existing studies focus on reducing the impacts of measurement uncertainty by developing uncertainty tolerant methods without quantifying the measurement uncertainties themselves. They therefore fail to fundamentally solve them. This study aims to directly quantify the measurement uncertainties of water flow meters in multiple water-cooled chiller systems using a Bayesian approach. A measurement uncertainty quantification strategy is proposed based on Bayesian inference and energy balance models, and the Markov chain Monto Carlo method is used to achieve the strategy. The site data collected from a chiller system are used to test the strategy. Four simulation tests with different levels of measurement uncertainty are conducted to further test and systematically validate the strategy. Test results show that the measurement uncertainties (both systematic and random uncertainties) of the water flow meters in the chiller systems can be quantified effectively and with acceptable accuracy. The strategy performs very well in quantifying random uncertainties of flow meters, and the relative errors range from 0% to 12.8%. The performance of the strategy in quantifying systematic uncertainties is also satisfactory, and the relative errors range from 0.1% to 36.57%. The proposed strategy is able to quantify measurement uncertainties and can be used to optimize the control of chiller systems and improve the reliability of chiller systems.

LNG mass flow measurement uncertainty reduction using calculated Young’s modulus and Poisson’s ratio for Coriolis flowmeters

We have proposed new methods to reduce the LNG mass flow measurement uncertainty using a Coriolis mass flowmeters (CMF). Since the uncertainty in the corrected Young’s modulus of meter tube is the dominating contribution factor, it is proposed to derive the Young’s modulus at LNG temperature using the calculated LNG density and the natural bending frequency measurement. The expanded uncertainty of the calculated Young’s modulus is evaluated to be 0.071%, which will enable the LNG mass flow measurement uncertainty of a straight-tube CMF to be reduced from 0.50% to 0.20% (k=2). This approach has the potential to provide more accurate LNG mass flow measurement in comparison to conventional methods which use the corrected Young’s modulus at LNG temperature. We have analysed the error in flow measurement using a U-tube CMF. An extra mass flow factor is shown to be the dominating mass flow measurement uncertainty factor due to the high uncertainty in the measured Poisson’s ratio of the tube. A new method is proposed to calculate the Poisson’s ratio from the torsional frequency and bending frequency measurements, with expanded uncertainty of 0.14%, 13 times lower than that of the measured values. The LNG mass flow measurement uncertainty of a U-tube CMF is estimated to be to 0.24% (k=2) using the calculated Poisson’s ratio and Young’s modulus. Our theoretical analysis shows that accurate estimation of Young’s modulus and Poisson’s ratio can significantly reduce the LNG mass flow measurement uncertainty using a CMF.

Study on the parallel pressure differential type gas laminar flow sensing technique

Parallel pressure differential (PPD) type laminar flow sensing technique was invented several years ago to reduce nonlinear effect in a traditional laminar flow element (LFE). In this paper, the internal flow of each branch in a PPD LFE is numerically simulated for gas flow. The results show that the relative deviation of the pressure drops of the two branches in a PPD LFE is within ±0.05% as inlet mass flow being the same, indicating that the flow resistance characteristics of the two branches are consistent, which means that the hypothesis of a same flow rate for the two branches in a real PPD LFE is tenable. There is little difference, ±0.01%, in the local pressure losses of the two upstream capillaries outlet flows, which can be ignored in a real measurement, further verifying that the theoretical analysis of the PPD principle is reliable. Capillary length effect in a PPD LFE is also examined. The bigger capillary length, the higher measurement precision can be achieved for a certain length range. For instance, it is suggested that the length of the short components should not be shorter than the laminar flow dimensionless entrance length defined by Xe (Le/d/Re, where Le is the entrance length) = 0.035, for flow measurement uncertainty within ±1.0%. The simulation and experiment results of gas flow show that the suitable value of Kexp is 1, and in the flow range of (0.0256–5.2985) m3/h measurement error of a PPD LFE is within ±0.8% only with expansion correction, indicating that the PPD laminar flow measurement technique is suitable for the gas flow.

Influence of flow disturbances on the performance of industry-standard LNG flow meters

In the last decade significant progress has been achieved in the development of measurement traceability for LNG inline metering technologies such as Coriolis and ultrasonic flow meters. In 2019, the world's first LNG research and calibration facility has been realised thus enabling calibration and performance testing of small and mid-scale LNG flow meters under realistic cryogenic conditions at a maximum flow rate of 200 m3/h and provisional mass flow measurement uncertainty of 0.30% (k = 2) using liquid nitrogen as the calibration fluid. This facility enabled, for the first time, an extensive test programme of LNG flow meters under cryogenic conditions to be carried out to achieve three main objectives; the first is to reduce the onsite flow measurement uncertainty for small and mid-scale LNG applications to meet a target measurement uncertainty of 0.50% (k = 2), the second is to systematically assess the impact of upstream flow disturbances and meter insulation on meter performance and the third is to assess transferability of meter calibrations with water at ambient conditions to cryogenic conditions. SI-traceable flow calibration results from testing six LNG flow meters (four Coriolis and two ultrasonic, see acknowledgment section) with water in a water calibration facility and liquid nitrogen (LIN) in the LNG research and calibration facility under various test conditions are fully described in this paper. Water and LIN calibration data were compared and it was observed that the influence of removing the meter insulation on mass flow rate measurement accuracy can be more significant (meter error > ±0.50%) than the influence of many typical upstream disturbances when the meter is preceded by a straight piping length equal to twenty pipe diameters (20D) with no additional flow conditioning devices, in particular for ultrasonic meters. The results indicate that the correction models used to transfer the water calibration to cryogenic conditions (using LIN) can potentially result in mass flow rate measurement errors below ±0.5%, however, the correction models are specific to the meter type and manufacturer. This work shows that the target measurement uncertainty of 0.50% can be achieved if the expanded standard error of the mean value measured by the meter is smaller than 0.40% (k = 2). It is planned to repeat these tests with LNG in order to compare the results with the LIN tests presented in this paper. This may reveal that testing with an explosion safe and environmentally friendly fluid such as LIN produces representative results for testing LNG flow meters.

Measurements of Discharge through a Pump-Turbine in Both Flow Directions Using Volumetric Gauging and Pressure-Time Methods

This article presents the original procedures for measuring the flow rate using the pressure-time and the volumetric gauging method in the case of performance tests of a reversible hydraulic machine in either turbine or pump modes of operation. Achieving the lowest possible measurement uncertainty was one of the basic conditions during implemented machine tests. It was met using appropriate measuring procedures and high-class measuring equipment. Estimation of the uncertainty for both methods was made on the basis of an analysis consistent with current requirements in this respect. The pressure-time method was supplemented by the computational fluid dynamics (CFD) analysis that allowed reducing the impact of the pipeline complex irregular geometry on the uncertainty of flow measurement. Appropriate modifications of the calculation procedure enabled accurate measurements of flow during the pump mode of operation of the tested machine as well. The volumetric gauging method, thanks to a special procedure used for accurate measurement of the water level in the upper reservoir of the power plant, allowed measuring the discharge through the tested reversible machine with very low uncertainty. The obtained results allowed for a detailed comparison and mutual verification of the methods used to measure the discharge of the tested reversible machine in both modes of its operation. The most possible causes of obtained results are discussed and summarized in the paper. The need for further research was pointed out to explain the differences obtained and their influence on the accuracy of discharge measurement using the pressure-time method in pump operation mode.

Uncertainty of mass flow measurement using centric and eccentric orifice for Reynolds number in the range 10,000 ≤ Re ≤ 20,000

Abstract The article analyses the impact of the Reynolds number on the estimated uncertainty of the mass flow rate measurement using an orifice plate. The objects of the research were two types of orifices: centric (ISA) and eccentric, with the diameter ratio β = 0.5. Studies were performed by Monte Carlo simulation and experiments for Reynolds numbers in the range 10,000 ≤ Re ≤ 20,000. The obtained results have shown that for both orifice types, the results obtained from the experiments and from the Monte Carlo simulation are similar. The nature of changes in the expanded uncertainty of the flow measurement is very similar for each type. For the both types of orifices, the value of the expanded uncertainty of the flow measurement increases linearly with the increasing Reynolds number.

Design of experiments to analyze the influence of water content and meter factor on the uncertainty of oil flow measurement with ultrasonic meters

This work aims to evaluate the influences of the water content dissolved in crude oil and of the meter factor on the uncertainty of the fiscal oil measuring system using ultrasonic flow meters, considering that the overall uncertainty of the measuring system shall not exceed 0.3%. The development of this work was motivated by the fact that the Brazilian Technical Regulation for the Measurement of Oil and Natural Gas (RTM) limits which methodologies can be used for water analysis and defines the maximum permissible uncertainty for the oil flow meter in which this analysis is inserted. However, the RTM does not define the uncertainty required for the water analysis. There is a risk of adopting one of the permitted methods of analysis and, even so, the measurement uncertainty of the flow meter exceeding the values defined by the legislation. In addition, the RTM adopts a repeatability criterion when validating the calibration of ultrasonic meters, thus the influence of this aspect on the oil uncertainty is also evaluated. The methodology used is the design of experiments and response surfaces. The results demonstrate that it is possible to simulate the influence of the water content and of the meter factor uncertainties on the overall uncertainty of the oil flow measuring system. Finally, the conclusions show that the average uncertainties currently observed for the water content are adequate to keep the oil measuring system uncertainty within the range allowed by the RTM, but small variations may cause this limit to be exceeded. The influence of the meter factor uncertainty was less than or similar to the influence of the water content. Finally, adoption of an acceptance criterion for the ultrasonic meters based on the uncertainty instead of repeatability is suggested.

Uncertainty Analysis for Mean Flow Velocity and Discharge Measurements using Floats based on Large-Scale Experiments

The uncertainty of flow measurements obtained by the float method is evaluated following the international organization for standardization (ISO) 748 guideline. However, the standard uncertainty of an average flow rate has not been considered and the quantitative uncertainty has never been computed for flow measurements made using the float method. Therefore, in this study, a stream-scale experiment was performed to estimate the standard uncertainty of the mean flow velocity by considering the flow velocity uncertainty of floats. The results demonstrated that the standard uncertainty of the mean flow velocity measured by a surface float was 15.30%, while that measured by a rod float having a 50-cm draft was 11.05%. Through these results, the measurement uncertainty of discharge was evaluated according to the GUM (guide for the expression of uncertainty in measurement) method. The measurement uncertainty was then evaluated considering the standard uncertainty of the mean flow velocity. The measurement uncertainty of the discharge was increased by 3.4% as compared with that calculated without considering the standard uncertainty.

Flow rate measurements in hydropower plants using the pressure-time method – Experiences and improvements

One of the most difficult tasks in the performance tests of hydraulic machines (turbines and pumps) is related to measuring the flow rate (discharge). Particularly, this problem concerns the large-size structures, which can be found in hydropower plants. In such cases, flow rate measurement is difficult and expensive due to the need to use special measuring devices assuring sufficiently low uncertainty level of measurement results in structures of such sizes, complex geometry, difficult access to the measurement cross-sections, etc. Only a few methods fulfilling this requirement are available under the conditions occurring in hydropower plants. One of them is the pressure-time method (known as the Gibson method) which is primary method of flow rate measurement particularly used in hydropower plants equipped with large-scale derivation.The Authors present some own experiences on flow rate measurements carried out by means of the pressure-time method gathered during tests performed in hydropower plants. Presented issues are related to instrumentation, measurement methodology and computation of the flow rate based on the recorded time course of pressure difference changes in penstocks of hydraulic machines installed in hydropower plants.Improvements in the pressure-time method developed on the basis of the aforementioned experiments allow to extend the applicability of the method, e.g. to measure flow in pump mode of hydraulic machines and reduce the uncertainty of flow measurement by applying elastic waterhammer theory based approach or CFD analysis in pipelines with complex geometry.

Accuracy improvement of virtual pump water flow meters using calibrated characteristics curves at various frequencies

The water flow rate of a pump can be calculated using other measurable inputs along with calibrated pump characteristic curves. Head-based and power-based virtual pump water flow meters apply the affinity laws to convert the calibrated pump head and power curves at the rated frequency to the curves at measured frequency and then calculate the water flow rate using measured head and power respectively. Due to the mismatched correlation between the motor speed and input frequency, these two flow meters cannot achieve acceptable accuracy. The purpose of this paper is to improve the accuracy of these two flow meters using the calibrated head and power curves at multiple frequencies rather than at the rated frequency only. First the mathematical models of flow measurements and uncertainty analysis are introduced, then two experiments are conducted, one for the virtual meter calibration and uncertainty analysis while another for the accuracy improvement validation. The results show that the uncertainty of water flow measurements decreases from 13 m3/h to 5 m3/h for the head-based flow meter and 17 m3/h to 6 m3/h for the power-based flow meter if the calibrated pump characteristic curves at multiple frequencies replace the curves at the rated frequency.

Determination of the uncertainty of mass flow measurement using the orifice for different values of the Reynolds number

Standard orifice flowmeters are widely used in the chemical and energy industry. Therefore, it is essential to know how accurate the measurements made with these instruments are. The paper presents an estimation of measurement uncertainty of a liquid mass flow using the orifice plate. The authors will present the influence of ranges of the Reynolds number on the estimated uncertainty, obtained on the basis of simulation and laboratory experiments. The research was conducted for the central orifice in the Reynolds number 8,000 < Re < 21,000. The results of estimating the extended uncertainty of the measurement of water flow using simulation and experimental method, are convergent. The maximum difference in the extended uncertainty values of flow measurement for the simulation and experiment was 0.04.10-3 kg/s.

Simulated time-dependent data to estimate uncertainty in fluid flow measurements

Abstract Positron Emission Particle Tracking (PEPT) is an emerging measurement technique for Lagrangian data collection in experimental fluid flows. The nature of the measurement extends the study of turbulent flows to applications lacking optical access. A simulated pipe flow PEPT measurement is used in this work to verify reconstruction algorithm and identify novel sources of uncertainty. Simulated measurement occurs in a 38 mm diameter pipe with 0.55 m/s mean flow velocity and Reynolds number equal 21,000. Flow is simulated using computational fluid dynamics (CFD), generating 1000 time-dependent trajectories of tracers from CFD to prescribe movements of 40 µCi, fluorine-18-point sources. Geant4 Application for Tomographic Emission (GATE) simulates the response of the Inveon Pre-Clinical scanner model and produces an array of coincidence lines for the prescribed sources. The array is provided to a multiple PEPT (mPEPT) code reconstructing the position of simulated tracers and assigns positions to coherent trajectories. The mPEPT reconstructed trajectories are compared to prescribed positions. Reconstruction of 754 trajectories is achieved with measurement bias centered at 0.0 mm in all directions and standard deviation of 0.29 mm, 0.29 mm, and 0.30 mm in the x, y, and z component respectively using 2.0 ms time-steps. Two instances of position misassignments induced by the close-approach of two tracers in measurement volume are identified. This is a novel reconstruction error to PEPT measurements, unable to be identified without prior knowledge of tracer trajectories provided by these simulation tools.