Decreasing Mass Flow Research Articles

Flow characteristics and factors affecting flow pulsation of external meshing herringbone gear pump

To enhance the outlet flow stability of the external herringbone gear pump, an analysis was conducted on the main influencing factors, key geometric parameters were identified, and a numerical model was developed for fluid analysis. A numerical model was then established for fluid analysis. The accuracy of the numerical model was verified by comparing it with experimental results, with simulation errors of displacement and volumetric efficiency being < 5%, ensuring the simulation's accuracy. The simulation results indicated that the pump's head (49.7808 m) and outlet pressure (4.9285 bar) remained stable. At 700 rev/min, the simulated volumetric efficiency was 82.94%. Subsequently, the impact of helix angle, changes in center distance, and tip clearance on outlet flow stability were analyzed. The analysis revealed that increasing the helix angle from 27° to 30° could reduce flow pulsation. A slight reduction in center distance from 180.3 (δ = +0.3 mm) to 179.9 mm (δ = −0.1 mm) effectively decreased mass flow difference and outlet pressure pulsation, enhancing outlet output stability. Reducing tip clearance from 0.25 to 0.12 mm, while meeting design requirements, resulted in more stable pressure and lift output. These results ensured smooth pump operation, improved outlet output stability, and met low-flow pulsation requirements. This study offered valuable insights into the design and production of the external meshing herringbone gear pump.

Investigation of the mild surge in an axial–centrifugal compressor

The performance and structural integrity of compressors are critically impacted by aerodynamic instability. This study examines an unstable phenomenon, known as high-frequency mild surge (HFMS), in axial–centrifugal compressors through an experimental investigation and a low-order model. The results reveal that the pressure signal during HFMS is synchronized along the circumferential and streamwise directions. To elucidate the HFMS mechanism and further explore its influential law, a multi-actuator model is developed, successfully capturing the dynamic instability behavior. As the mass flow decreases, the front axial stage becomes unstable first, while the latter centrifugal stage remains stable with a negative slope near the operating point on the performance curve. The strong pressurization of the centrifugal stage maintains the stability of the entire compression system, increasing the mass flow rate. Subsequently, the pressure ratio of the latter centrifugal stage decreases with increasing mass flow, causing the front axial stage to become unstable again. The axial stage's Helmholtz frequency is consistent with the test HFMS frequency, further proving that it is a local systematic instability dominated by the axial stage. This matching feature is particularly common in combined compressors, making HFMS a typical instability phenomenon in such systems.

Research on an optimization design method for a TBCC propulsion scheme

Abstract An optimization methodology for a TBCC propulsion schemes was established for hypersonic vehicles, focusing on the integration of aircraft and engine performance. Altitude-velocity characteristics of TBCC propulsion were obtained through engine performance calculations. By analyzing mission requirements, lift-drag characteristics, and flight constraints, the take-off thrust-weight ratio and wing load of the vehicle were optimized to meet the flight conditions. In addition, the fuel ratio was calculated. To determine the vehicle’s gross take-off weight and the engine’s take-off thrust, a model considering the weight of the vehicle and the turbine engine were used. The optimization process selects four thermodynamic cycle parameters for the turbine engine as the independent variables. An improved particle swarm optimization-back propagation neural network was used to establish the relationship between the four parameters and the gross take-off weight, aiming to minimize the vehicle’s weight. The results of the optimization process show that the total take-off weight of the optimized vehicle has decreased from 112363.41 kg to 102218.98 kg. The required uninstalled take-off thrust of TBCC has also been reduced from 162.86 kN to 147.49 kN, resulting in a decrease in mass flow from 156.50 kg/s to 133.30 kg/s.

Dynamic mode characteristics of flow instabilities in a single-stage compressor under different throttling processes

To investigate the influence of throttling processes on dynamic characteristics of compressor stability, the rotating stall development of National Aeronautics and Space Administration Stage 35 was simulated with full-annulus Unsteady Reynolds-Averaged Navier–Stokes under different throttling processes. The numerical methods were verified. By combining Dynamic Mode Decomposition and flow field evolution research, the flow structures and dynamic characteristics of “critical mass flow” under different throttling processes were deeply studied; the flow mechanism of flow instabilities under different throttling processes was explored. It is found that the “critical mass flow” corresponds to the beginning of a rapid decrease in mass flow, mainly characterized by shock forward movement and a larger range of spillage flow. Around “critical mass flow,” if the throttle is still tightening, it presents stall pattern 2; otherwise, it presents stall pattern 1. During the pre-stall, both patterns are dominated by tip clearance vortex (TCV)-shock interference. Stall inception disturbance is generated from TCV-shock interference; pattern 1 presents a single disturbance, while pattern 2 presents multiple disturbances. Subsequently, the TCV-shock interference gradually weakens. The single stall disturbance of pattern 1 gradually develops and stabilizes. The multiple stall disturbances in pattern 2 undergo processes including fusion and disappearance, ultimately developing into a single stall cell. During the stable stall, the throttling processes have no significant impact on the speed of the stall cell, and the flow in the un-stalled region is basically consistent with the speedline. However, the tighter the throttle is, the larger the stalled region, and the weaker the flow capacity of the un-stalled region.

Experimental investigation of regenerative cooling performance in hybrid rocket engines

An experimental investigation regarding the reliability and feasibility of a regenerative cooling system in hybrid rocket engines is presented. The novelty of the work is the introduction of a regeneratively cooled carbon-based nozzle throat using liquid oxidizer, for thermal management of the detrimental heat fluxes developed in the nozzle. The benefits and drawbacks of using regenerative cooling based on the observations of the current experimental campaign are critically discussed. Cryogenic oxygen in subcritical conditions is used as a coolant and oxidizer, for combustion with a fuel grain of high-density polyethylene stored within the combustion chamber. Pressure and temperature measurements are taken from multiple locations in the oxygen feed line and within the graphite nozzle throat. Eight firing tests were performed under various oxidizer mass flow rates and thus various thrusts. It was confirmed that cooling the graphite throat prevented the occurrence of nozzle erosion in all eight firing tests. The heat transfer rate and the physical state of the coolant are evaluated indirectly. Results show that increasing coolant gasification correlates with decreasing mass flow rate. The cooling performance improved more with higher vapour fractions than larger mass flow rates, however, dry-out occurred in tests with the highest gasification level. In summary, is it shown that while the current regenerative cooling system will supress nozzle erosion and limit nozzle temperatures in long duration firing, it reduces the predictability of flow rate and thus thrust during operations.

Parametric evaluation of compact truncated Venturi flow meters

Venturi flow meters are pressure differential devices that perform accurate measurements with minimal pressure losses. They are widely used and well-documented in high-Reynolds applications. However, there is a lack of information regarding their performance outside the standards. The premise of the present study is to characterize a single-phase subsonic compact truncated venturi flow meter experimentally and then extend the research using Computational Fluid Dynamics (CFD). The computational work results in a design of experiment with 216 unique geometries at three different flow conditions (648 cases). This allows for characterizing the pressure losses and discharge coefficient as a function of diameter ratio (0.3–0.8), recovery cone truncation (0 %–50 %), and divergent angle (5°–20°). The thorough analysis of the results yields an intricate flow interaction and dependency on the studied parameters. The study covers throat Reynolds numbers from 7∙103 to 7∙104. In this regime, uncertainty in mass flow measurement increases notably (up to 20 %) with a decrease in mass flow. Pressure losses are sensitive to the three studied parameters, while the discharge coefficient can be considered to be independent of divergent angle and truncation. Truncating the Venturi at 50 % can increase the pressure loss coefficient by over 15 %. The optimal divergent angle and truncation to minimize losses for a prescribed length are provided for the instances where the installation space is constrained. This manuscript includes design guidelines relevant to all experimentalists.

Control strategies of pumps in organic Rankine cycle under variable condensing conditions

The working medium pump and cooling water pump are important components in organic Rankine cycle system. However, they have not received as much attention as the expander and working medium. Simultaneously, the dramatic changes in condensing environment deviate the organic Rankine cycle working point from the designed operating conditions. Hence, this paper focused on the performance improvements and control strategies of working medium pump and cooling water pump in small-scale organic Rankine cycle under variable condensing conditions. A model was established to predict the performances of an organic Rankine cycle system with R245fa, especially the pumps in the system, under variable condensing conditions. The results showed that the overall efficiency of multi-stage centrifugal pump was between 14% and 39% at an estimated speed of approximately 1600 RPM to 2328 RPM. In winter conditions, the back work ratio increased from 0.05 to 0.19 with increasing evaporation pressure and decreasing mass flow rate. In other words, it is unnecessary to pursue excessively high evaporation temperature at low rotational speed of multi-stage centrifugal pump. As for the cooling water pump, it is feasible to reduce the power consumption of the cooling system through changing the rotational speed of water pump. The water pump can be operated with high efficiency (between approximately 58.4% and 65.3%, corresponding to an estimated speed range of 1374 RPM to 1813 RPM) when the system run in optimum operating conditions. It is also found that the performance of organic Rankine cycle was strongly influenced by fluctuating ambient temperature, with the net efficiency and net power increase of 3.36 % and 5.11 kW in winter compared to summer.

Heat Flux Determination from Pressure Data for a Transpiration Cooling Environment

This paper describes a new heat flux gauge for application in transpiration cooled environments. The sensor is a transpiration cooled porous element and the surface heat flux is determined from the plenum pressure trace. The sensor is characterized using the non-integer system identification method. It was calibrated at four constant mass flow rates, i.e., 15, 30, 45, and 60 mg/s, of nitrogen. Toward higher mass flow rates, stronger system response is observed. The sensor performance was determined by the analysis of a well-known Gauss function-shaped heat flux profile. The deviation is below 18%. The sensor was applied to heat flux measurements in the plasma wind tunnel PWK4 at the University of Stuttgart. The stagnation point heat flux was determined to be 20 to 395 kW/m2 for decreasing mass flow rates. From this data, the local freestream mass-specific enthalpy of 10.5 MJ/kg and uncooled surface heat flux of 1042 kW/m2 were calculated based on the stagnation point heat flux reduction over the mass flow rate increase.

Thermodynamic assessment and optimization on louver fin with non-uniform arrangement at different tube rows by desirability approach

The parametric study explores the thermodynamic performance of louver fin with non-uniform arrangement at different tube rows based on three factors: Reynolds number (Re), number of slotted at first tube row (Ns1), and number of slotted at second tube row (Ns2). The distributions of local entropy generation are displayed and analyzed in detail. Thermal entropy generation is mainly concentrated in the first row, but the viscous entropy generation of the first row is roughly the same to the second row. Compared with plate fin, the louver fins can effectively reduce thermal entropy generation, but also bring greater viscous entropy generation at variable Re. The thermal entropy generation and viscous entropy generation increase, but the thermal entropy generation per unit mass flow decreases and the viscous entropy generation per unit mass flow increases as the increasing Re. It is found that the increase in Ns1 will lead to a far greater improvement in thermal performance than the increase in Ns2. However, the increase in resistance caused by the increase in Ns1 is approximately equal to the increase in resistance caused by the increase in Ns2. Meanwhile, the correlations of the thermal performance and resistance are given, which facilitates the design of the heat exchanger. The non-uniform arrangement is quantitatively optimized using the desirability approach, and the arrangement of first-dense-then-sparse at Re = 900, Ns1 = 8, Ns2 = 4 is given. The arrangement of first-dense-then-sparse can reduce the resistance without reducing the thermal performance evidently.

CFD analysis of porous flow blockage in a gas-lift enhanced LBE-cooled fuel assembly

Porous blockage is likely to occur in wire-wrapped fuel assemblies and cause severe consequences such as overheating and mass flow decrease. In this study, flow behavior upstream, inside and downstream of the blockage is obtained for different porosities to analyse the overheating and pressure change. Additionally, the effect of reactivity feedback considering the void fraction and radial and axial power distributions on LBE-cooled porous blockage are given. It is concluded that flow separation upstream and recirculation downstream is the main reason for the overheat phenomenon due to poor convective heat transfer. Static pressure has a local rise both upstream with small porosities and in the flow recovery region downstream, while the gradient of pressure drops inside the blockage is large and begins forwards for small porosities because of flow resistance. The study of reactivity insertion reveals that although the effect of the void fraction on the reactivity and heat power is straightforward, the volume-averaged coolant and rod temperatures are virtually unaffected within 0.02 s. The wall and bulk temperature of central blockage C1 is generally higher than that of edge blockage E1.

Elevated atmospheric CO2 suppresses silicon accumulation and exacerbates endophyte reductions in plant phosphorus

Abstract Many temperate grasses are both hyper‐accumulators of silicon (Si) and hosts of Epichloë fungal endophytes, functional traits which may alleviate environmental stresses such as herbivore attack. Si accumulation and endophyte infection may operate synergistically, but this has not been tested in a field setting, nor in the context of changing environmental conditions. Predicted increases in atmospheric CO2 concentrations can affect both Si accumulation and endophyte function, but these have not been studied in combination. We investigated how elevated atmospheric CO2 (eCO2), Si supplementation, endophyte‐presence and insect herbivory impacted plant growth, stoichiometry (C, N, P and Si), leaf gas exchange (rates of photosynthesis, stomatal conductance, transpiration rates) and endophyte production of anti‐herbivore defences (alkaloids) of an important pasture grass (tall fescue; Lolium arundinaceum) in the field. eCO2 and Si supplementation increased shoot biomass (+52% and +31%, respectively), whereas herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%. Shoot Si concentrations, in contrast, decreased by 17%–21% under eCO2. Si supplementation and herbivory reduced shoot C concentrations. eCO2 reduced shoot N concentrations which led to increased shoot C:N ratios. Overall, shoot P concentrations were 26% lower in endophytic plants compared to non‐endophytic plants, potentially due to decreased mass flow (i.e. observed reductions in stomatal conductance and transpiration). Alkaloid production was not discernibly affected by any experimental treatment. The negative impacts of endophytes on P uptake were particularly strong under eCO2. We show that eCO2 and insect herbivory reduce and promote Si accumulation, respectively, incorporating some field conditions for the first time. This indicates that these drivers operate in a more realistic ecological context than previously demonstrated. Reduced uptake of P in endophytic plants may adversely affect plant productivity in the future, particularly if increased demand for P due to improved plant growth under eCO2 cannot be met. Read the free Plain Language Summary for this article on the Journal blog.

Numerical Study of Flow Control on Simplified High-Lift Configurations

Enhancement in the aerodynamic performance of wings and airfoils is very notable when Active Flow Control (AFC) is applied to Short Take-off and Landing aircraft (STOL). The present numerical study shows the application of steady, pulsed and synthetic tangential jets applied to the plain flap shoulder of a modified NASA Trapezoidal Wing. Pulsed jets are modeled by sinusoidal and square waveforms while synthetic jets are modeled only by pure sine waveform. The freestream airflow conditions are Mach number equal to 0.2 and Reynolds number equal to 4.3 million based on the mean aerodynamic chord. The presented simulations are two-dimensional and based on RANS for steady jet cases and URANS for pulsed and synthetic cases, compiled with the open-source suite SU2 and adapted for time varying boundary conditions. Numerical results for modified configurations based on the same baseline wing profile considering different leading edges, jet slot height, flap position, blowing mass flow, type and frequency of the jets are presented. Curves of pressure coefficient distribution revealed a substantial influence upstream of the AFC, around the slat and main element. The jet slot height analysis showed that the lift gain is also influenced by the slot size due to the change of the local flow velocity considering the same blowing momentum coefficient. Regarding the jet frequency, no significant differences on the lift coefficients were found between the reduced frequencies F+ equal to 1 and 2. Results of aerodynamic loads showed an improved lift coefficient in relation to the baseline airfoil when pulsed and steady jets are employed. Pulsed jets under square waveform were effective even at high deflected flap condition at 50°, with a significant gain in the lift coefficient of 36%, in relation to the uncontrolled case, combined with a drag reduction of 20%, and a decrease in mass flow up to 49% in relation to the steady jet for the same lift gain. Although sine and square waveform results presented similar improvements for lift, the drag is around 15% higher for the former. When compared with the steady jet case, the mass flow reduction is 36% for the sinewave. Synthetic jets with zero-net-mass-flux proved superior to the baseline conventional multi-element airfoil only with deployed flap at 50°, where a modest lift improvement of 5% was observed.

Effects of operating parameters on the performance of moving bed filter

High-temperature gas purification technique is of great significance for environmental protection. Moving bed filtration is considered a promising technique. In this study, the moving granular bed filter with the gas-solid counter flow was proposed. The pressure drop and the collection efficiency were investigated with respect to the superficial gas velocity, the mass flow rate of the filtration granules and the dust inlet concentrations. In addition, the dust concentrations at different bed heights were measured with isokinetic sampling. The experimental results indicate that an increasing filter gas velocity or a decreasing mass flow rate of the granule leads to a decrease in dust collection efficiency. An empirical equation was given by combining the single particle filtration analysis with the measured dust concentration distribution along the vertical height of the filter to calculate the moving bed filtration efficiency.

Effect and Mechanism of Roughness on the Performance of a Five-Stage Axial Flow Compressor

In order to prolong the service life of multistage axial compressors, it is increasingly important to study the influence of blade surface roughness on the compressor performance. In this paper, a five-stage axial compressor of a real aero-engine was selected as the research object, and an equivalent gravel roughness model was used to model the roughness based on measured blade surface roughness data. Furthermore, the impact of blade surface roughness on the performance at design rotational speed was studied by full three-dimensional numerical simulation, and the mechanism of performance variation caused by the roughness was discussed combined with quantitative and flow field analyses. The results show that, when the blade surface roughness of all blades increases, the peak total efficiency decreases by approximately 0.4%, the blocking mass-flow decreases by approximately 0.3%, and the stable working range changes little. When the surface roughness of all rotor blades increases, the performance decline is close to that of all rotor and stator blades, and the variation in stator blade roughness has little effect on the compressor performance. Regarding the variation in roughness, the performance of the latter stage is more sensitive than that of the previous stage, and the decline in the performance of the fifth stage contributes the most to the total performance degradation of the compressor. Once the surface roughness of the fifth-stage rotor blade increases, the flow in the middle of the rotor blade deteriorates and the stage performance decreases obviously, which is the main reason for the decline in the overall performance.

Experimental study on continuous spectrum bubble generator with a new overlapping bubbles image processing technique

• The CSBG, which can produce bubbles with continuous sizes is developed. • Experimental results show that CSBG can generate bubbles of continuous sizes. • Overlapping bubbles processing technique (OBPT) based on CPD & FSAC is proposed. • Accuracy of OBPT exceeds 95% with a sub-second response time per hundred bubbles. The parameter of bubble size is of great significance to the bubbly flow. In this paper, the Continuous Spectrum Bubble Generator (CSBG), consisting of a sparger and impeller, was developed to realize the continuous control of bubble sizes. By introducing a new variable, rotation rate of the impeller, bubble size and gas superficial velocity are successfully decoupled. Experimental results show that bubble sizes continuously drops from 3 to 1 mm, without changing gas superficial velocity. Also, the spectrum of bubble size can be expanded by increasing or decreasing mass flow rates. To detect the overlapping bubbles, a new overlapping bubbles processing technique based on fast segmented arcs clustering was proposed. It’s efficient to cluster the segmented arcs through detecting the Major and Pair arcs and connecting the Multi-segment arcs through concave points connection methods. Test results show that the accuracies of mean diameter exceed 95% with sub-second response time per hundred bubbles.

Fire risk problem of aluminum foundry

During various modes of operation of the melting furnace, a large amount of aerosol particles consisting mainly of amorphous carbon is generated irregularly depending on the current state (especially during the loading of the return material), accompanied by the development of significant amounts of volatile organic compounds and methane. The resulting mixture of organic substances is not quantitatively eliminated in the afterburner chamber of the melting furnace. The VOC mass flow remains almost unchanged and only the methane mass flow decreases. The mass flux of aerosol particles, on the other hand, increases after passing through the afterburner chamber, with particles of aluminium metal contributing significantly to this increase. The aerosol particles trapped on the textile filter of the melting furnace are thus composed of particles of amorphous carbon and particles of inorganic origin (metallic aluminium and limestone). The structure and surface properties of the carbon particles pose a significant risk of textile filter ignition. From the measurement results obtained, the following solution to the hazardous condition of the plant can be found: (a) a change in the existing technology, for example: changing the design of the part of the melting furnace into which the return material is fed; changing the heat input and the mode of the gas burner and fan in this part of the furnace; a significant reduction of the flue gas flow in the A-gauge and afterburner chamber or change of machining emulsion; (b) the installation of an additional gas burner in the newly installed afterburner chamber, to which the flue gases from the part of the melting furnace into which the return material is fed would be discharged in the existing return material inlet mode.

Numerical simulation of complex thermal decomposition processes in pyrolysis furnace for recycling solid waste Mg(NO3)2.2H2O

This study aims to reveal the complex thermal decomposition processes in a pilot-scale pyrolysis furnace for recycling solid waste Mg(NO3)2.2H2O produced in nitric acid leaching process of laterite nickel ore, by using CFD method. Specifically, an integrated mathematical model combining the gas-particle flow and the thermal decomposition reaction as well as the heat, mass transfer between gas and particle was developed based on the Euler-Lagrange method. And then, the developed model was used to study the flow characteristics of the gas and particle and the thermal decomposition processes for Mg(NO3)2.2H2O in the pyrolysis furnace. Furthermore, the effect of operating parameters (gas inlet temperature, mass flow rate and particle size of Mg(NO3)2.2H2O) on the performance of pyrolysis furnace (decomposition rate of Mg(NO3)2.2H2O) was studied. The results show that the developed model is reasonable. Increasing gas inlet temperature, decreasing mass flow rate and particle size of Mg(NO3)2.2H2O can effectively promote the decomposition rate of Mg(NO3)2.2H2O. Under the conditions of gas inlet temperature 1123 K, mass flow rate of Mg(NO3)2.2H2O 200 kg/h, and average particle size of Mg(NO3)2.2H2O 75 µm, the dehydration reaction mainly occurs in the furnace height of 11–8 m, while the denitration reaction mainly occurs in the furnace height of 10.5–1 m. The total decomposition rate of Mg(NO3)2.2H2O is 99.75%.

Evaluation of polymeric membranes’ performance during laboratory-scale experiments, regarding the CO2 separation from CH4

The present study evaluates the separation performance of a commercially available polymeric membrane, when employed for the upgrade of biogas to enrich CH4 from a simulated binary gas mixture. For this purpose, a laboratory-scale membrane set-up device has been designed and assembled, aiming to achieve the production of high purity biomethane (>95%) with simultaneous recycling and utilization of the (considered as) waste CO2 stream. The examined membrane is a polysulfone (PSF) hollow fiber (HF) one, applied in counter-current flow. The feed concentration of gases consisted between 55-70 vol% and 45–30 vol%, regarding CH4 and CO2 respectively, whereas the effect of retentate pressure was studied in the range between 0.7 and 1.5 bars. The experimental results reveal that the concentration of CH4 in the retentate stream can exceed the target value of 95%, when the applied pressure values are above the limit of 1 bar. Any increase in the feed pressure can lead also to higher CH4 purity on the retentate side, however the retentate mass flow decreases, leading to smaller recovery values of CH4. A significant increase in the CH4 purity is observed, when the CH4 recovery drops below 40%, suggesting the need for the application of multiple membrane modules, operating in series. Regarding the CO2 concentration in the permeate stream, its percentages range between 30 and 50%, which are not considered as sufficient to permit immediate reuse, whereas the need of extra membrane modules to improve the purity of gas streams is confirmed.

Thermal cracking and coke deposition characteristics of aviation kerosene RP-3 in an S-bend tube

In this work, an experimental study on the supercritical aviation kerosene RP-3 flowing inside an S-bend tube was conducted to examine the effect of the curved structure and mass flow rate on the thermal cracking and coke deposition behaviours. The results indicated that the conversion and gas yield in the S-bend tube were slightly higher than those in a straight tube. In particular, the maximum conversion in the S-bend tube was 70.1% at 700 °C, whereas that in the straight tube was 60.8%. This condition was attributed to the existence of high-temperature fuel in the near-wall region; this fuel was further pushed toward the core flow field under the effect of secondary flow and Dean vortices. In addition, secondary flow strengthened the fuel-mixing effect and increased the local resistance. A considerable peak in the coke deposition rate was observed in the first curved region of the S-bend tube. Moreover, the decreased mass flow rate had a promoting effect on thermal cracking and coke deposition, owing to the high fuel bulk temperature and coke precursor concentration.

Thermal performance of nanofluid with employing of NEPCM in a PVT-LFR system

A photovoltaic thermal- linear Fresnel reflector (PVT-LFR) modified with integration of phase change material (PCM) was investigated numerically in current paper. The impact of the different mass flow rates and influence of adding Al2O3 nanoparticles to the coolant and PCM on the performance of collector is evaluated. In order to model the PVT-LFR system a transient solver is chosen. The governing equations of the PVT-LFR are solved using CFD (computational fluid dynamic) approach. The SIMPLE algorithm was applied for coupling of velocity and pressure. The simulation is done under the constant solar radiation of 750 W/m2 for 20,000 s. The results show, that electrical efficiency of the system is reduced by decreasing mass flow rate and adding nanoparticles to the PCM, however, with adding nanoparticles to coolant, the electrical performance of the system is enhanced. The thermal output of the system enhances with increasing mass flow rate. Furthermore, adding nanoparticles to the water and phase change material has positive effect on the thermal output of collector.