## What is/are Pressure Drop?

Pressure Drop - For the same pressure drop requirement, the average convection to conduction heat transfer is up to 16% better when a pair of baffles are used, compared to an unobstructed flow.^{[1]}The percentage of pressure drop due to the breathing circuit were about 70% for all the groups (no differences statistically, p=0.

^{[2]}Taking into account new problems arising in the transportation of a steam-water heat carrier to support operation of geothermal power plants (GeoPP), a procedure is outlined for determining the void fraction considering the gravity component of the pressure drop in the hydraulic design calculations of steam-water piping.

^{[3]}Hence, porosities and defects due to pressure drops inside the laminate during impregnation and solidification can cause degradation in material properties.

^{[4]}A detailed parametric study is carried out to evaluate the impact of different arrangements of conical strip insert, Reynolds number, and volume fraction of nanoparticles ( $$\phi $$ ) on the heat transfer and pressure drop of the oval tube.

^{[5]}Because the pressure drop is small, the ascending magma enters the magma chamber slightly sulfide under-saturated and requires only a small amount of fractional crystallization to return it to sulfide-saturation.

^{[6]}The heat sinks suggested are formed from foamed-baffles arranged in-parallel or perpendicularly to the coolant paths via the staggered voids in between to alleviate the penalty of pressure drop while maintaining high heat dissipation capability.

^{[7]}Efficient vapor removal due to the increase in the manifold volume also lowers the pressure drop, thereby allowing maximum reduction in surface temperature of 4.

^{[8]}The influence of a deflector in a tank was numerically investigated based on uniform design method to improve the heat and mass transfer and pressure drop performance of the air-water direct tank.

^{[9]}The main blockages caused by the pressure drop in air-main, water-main and steam-main are indicated.

^{[10]}Finally, an in-depth parametric analysis is carried out with emphasis on the influence of governing parameters on PMD performances, such as dehumidification rate (DR), dew point approach temperature (DPAT), pressure drop (ΔP), and COP.

^{[11]}The data were taken at each flow condition, resulting in new holdup and pressure drop.

^{[12]}The optimization design variables included parameters such as turbine inlet temperatures and pressure, sCO2 cooler outlet temperatures, recuperator approach temperatures and pressure drops etc.

^{[13]}The model is validated by predicting the pressure drop changes during the 1D PPG injection experiments at three different flow rates.

^{[14]}More specifically, the simultaneous effect of screen and perforation parameters, near wellbore conditions on pressure distribution and pressure drop are investigated in detail.

^{[15]}The results show that the relative deviation of the pressure drops of the two branches in a PPD LFE is within ±0.

^{[16]}The influence of alternating of cross section on heat transfer and pressure drop of the channel was studied by comparing with the smooth elliptical U-bend channel.

^{[17]}Previous studies of PIG motion typically employed empirical experimental or reduced numerical data to extrapolate PIG velocities and pressure drops along the pipeline—while this could resolve issues specific to the case being studied, it does not go very far in developing an overall understanding of the dynamics of the system.

^{[18]}The first analysis was carried out to reproduce a wavy stratified flow to examine the effects of different simulation model set-ups according to the velocity and kinetic energy profiles, as well as the pressure drop gradient and the water level measured by Fabre 1987.

^{[19]}The study also investigated the pressure drop and pumping power of the PV/T collector with and without nanofluid.

^{[20]}However, when an MR shock absorber is applied to dynamic systems that require high stroke velocity, such as aircraft landing gear systems, the minor loss effect becomes significant to the pressure drop.

^{[21]}The results showed that the pressure drop increased with more micro-encapsulated phase change material (MEPCM) adding to the fluid.

^{[22]}On other hand, the experimental data were obtained in the literature, the authors used the Particle Image Velocimetry (PIV) technique to measure the velocity fields and a differential manometer to measure the pressure drop.

^{[23]}It was observed that the usage of flow passage above the channel also operates as a turbulator and results in more heat transfer and pressure drop because of more local vortexes.

^{[24]}The simulation considers a Brayton cycle for the power unit with irreversibilities in the compressor and turbine, and pressure drops in the heat absorption and extraction processes.

^{[25]}It is observed that the double corrugated geometry does not have a significant impact on the pressure drop inside the analysed heat exchanger, while it has the potential to increase its thermal performance by up to 25%.

^{[26]}6%), and the pressure drops recorded at the water levels of 6, 8 and 10 cm were 103, 122 and 153 mmH2O, respectively.

^{[27]}Searching for an analogy concept between heat transfer and pressure drop is anything but new, nevertheless it is still the subject of researches as it enables the prediction of heat transfer from pressure drop data, which helps reducing experimental effort for heat transfer measurements.

^{[28]}Moreover, two pressure sensors were integrated into a microchip to characterize the pressure drop in the microchannel.

^{[29]}The new model considered plenty of parameters that may have significant impacts on productivity and pressure drop in the well, including the fishbone structure, the main and branch wellbores’ length, the spacing distance of the branch wellbores, wellbore radius, and preformation parameters.

^{[30]}Additional investigations sought to verify the effect of the direction of perforations on the skin factor or pressure drop in perforated inclined wells.

^{[31]}Relative permeability is traditionally obtained in core flooding experiments from production data and pressure drop either using analytical methods or inverse modelling.

^{[32]}The pressure drop prediction of wet gas across single-orifice plate in horizontal pipes had been solved satisfactorily under an annular-mist flow in the upstream of orifice plates.

^{[33]}The influence of inlet cross-sectional shape on the flow pattern, pressure drop, and cut-off diameter of a gas cyclone was studied using the CFD model.

^{[34]}Several cases of installation of pumps working as turbines (PATs) in water distribution networks were analyzed in which the use of these recovery systems caused a pressure drop, reducing the level of leaks and recovering energy.

^{[35]}The investigation focuses on the effects that pressure magnitude, pressure drop and pressure ratio have on the temperature drop between the inlet and the cold outlet.

^{[36]}Pressure drop data within each flow section of the tool were obtained and the fluid densities determined.

^{[37]}The heat transfer, pressure drop and pumping power of Graphene Nano fluid were measured.

^{[38]}Finding the pressure drops that occur in the flow of spherical ice capsules with water is the basis of the research.

^{[39]}Even fluid flow and pressure drop distributions are verified by numerical models at given flowrates.

^{[40]}Usually, fouling make the pressure drop to increase.

^{[41]}A quasi-dimensional model of the CR fuel system was built to analyse the rail pressure wave fluctuation characteristics, and a parameter K was defined as the pressure drop rate.

^{[42]}The region of capillary end effect, which occurs due to the rupture of capillaries at the exit from the sample, affects the change in pressure drop and saturation of a particular fluid.

^{[43]}At the same time, in the production process, the pressure drop generated by the formation is mainly concentrated near the wellbore, which leads to a short period of waterless oil production, fast water breakthrough, and fast water cut rise, which seriously affects the overall recovery factor and increases the risk of oil filed exploitation.

^{[44]}An analytical model is used to approximate the thickness of the oil film formed at the back of the filter surface and the pressure drop caused by the gas flow through it.

^{[45]}Based on the segmented vessel, calculated velocity, and aortic pressure, AccuFFRangio distribution was calculated through the pressure drop equation.

^{[46]}Heat transfer and pressure drop in a functionally-graded foam, with a uniform heat flux entering one of its sides, are investigated numerically in this paper.

^{[47]}The size of microchannel limits the size of dp, making the thermo-hydraulic characteristics of gradient-dp mode worse than that of gradient-e under the same conditions, and the thermal resistance decreases as well as pressure drop increases with the augment thickness of porous media, so it is necessary to select the appropriate structural parameters and coolants according to the specific working conditions to obtain better comprehensive performance.

^{[48]}The flow velocity and pressure drop characteristics in the 3 × 3 rod bundle channel are investigated.

^{[49]}The purpose of this study is to investigate the possibility of allocating this ORC plant into a vehicle and in the design of the condenser, with the purpose of reaching the best configurations that lead to low-pressure drop and compact dimensions.

^{[50]}

## heat transfer coefficient

The subcooled boiling curves, heat transfer coefficient, and pressure drop were discussed with the variation of heat flux and mass flux, the trends of which were analyzed along with the flow patterns.^{[1]}For both cases, the results of the dimensionless Nusselt number, heat transfer coefficient, pressure drop, exergy efficiency, and energy efficiency are described.

^{[2]}Heat transfer coefficients and frictional pressure drops were evaluated from the experimental tests, and compared against values estimated by empirical correlations.

^{[3]}The influence of different corrugation heights on the heat transfer coefficient and the pressure drop has been studied.

^{[4]}Appropriate arrangement of the fin structures in the evaporator and condenser not only enhances the heat transfer coefficient but also suppresses the increase of pressure drop.

^{[5]}CFD analysis to determine the heat transfer coefficient, mass flow rate, heat transfer rate, pressure drop and velocity at different mass flow rates (1, 1.

^{[6]}In comparison with the base fluid data, the heat transfer coefficient, Nusselt number, pressure drop, pumping power, friction factor and the thermal performance factor of the ND nanofluid augment by 36.

^{[7]}The current study evaluates the pressure drops and heat transfer characteristics of water coolant flow at sub-atmospheric pressures for two different cooling configurations: 1) bare-die under jet impingement flow showcasing effective heat transfer coefficient well over 10 W/cm2-°C and 2) microchannel cold plate with thermal resistances less than half that of single-phase cooling with similar flow conditions.

^{[8]}pressure drops, heat transfer coefficient, anti-freezing solutions, cost and power block design.

^{[9]}For VB mode, a phase separator is installed inside the evaporator refrigerant circuit to bypass vapor refrigerant, which can increase the average evaporation temperature for retarding frosting by reducing refrigerant pressure drop and decreasing the area of refrigerant inferior heat transfer coefficient region (mist flow region).

^{[10]}Based on the measured heat transfer coefficients and pressure drops of wire gauzes, the empirical equations of friction and transfer characteristics of plain-square-type woven sheets are developed.

^{[11]}The decrement of channel diameter leads to greater heat transfer coefficients, pressure drop, friction factor but nearly the same Nusselt number.

^{[12]}, heat transfer coefficient, pressure drop, performance evaluation criteria, and fluid flow.

^{[13]}In this study, prediction methods of frictional pressure drop and heat transfer coefficient of flow condensation in a plate heat exchanger which were tailored for the applications in heat pump and organic Rankine cycle systems, were developed.

^{[14]}The heat transfer coefficient, air side pressure drop, water side pressure drop resistance and overall weight are used as the optimization objectives using genetic algorithm, to optimize structure parameters of the generator air cooler.

^{[15]}It was found that larger wave amplitudes raise the pressure drop and the heat transfer coefficient; however, the thermal performance parameter, which compares the relative importance of these two parameters, still follows an increasing trend.

^{[16]}Experimentally, the heat transfer coefficient and pressure drop of hybrid nanofluids with mass concentrations ranging from 0.

^{[17]}With Reynolds number varying from 5000 to 20,000, the results show that the heat transfer coefficient and pressure drop in the shell side of the heat exchanger both increase with the decrease of the hole height and the plate spacing of the QPP, but the shell side heat transfer coefficient per unit pressure drop h/Δp decreases.

^{[18]}Heat transfer coefficient and pressure drop per unit length of helical coils were taken as the optimization objective functions.

^{[19]}In the last section, the statistical approach with response surface methodology has been utilized to correlate and optimize the heat transfer coefficient and pressure drop of different fluids.

^{[20]}In this study, an experimental test loop has been constructed to study the PHE thermal characteristics, heat transfer coefficient, effectiveness , transmitted power and pressure drop at different volume fraction of Al2O3 nano-material (1% -4%) in pure liquid water as a base fluid.

^{[21]}Flow patterns, pressure drop, heat transfer coefficient, and cost per benefit ratio factors were the parameters that were studied in this paper.

^{[22]}In brief, the maximum used nanoparticle volume fraction of 5% results in an improvement of 75% for the heat transfer coefficient leading, in turn, to a reduction of 1% for the heat exchanger length and a pressure drop increase of 8%.

^{[23]}Dimples are widely known to increase heat transfer coefficients in internal passages with a minimal pressure drop.

^{[24]}The test reveals that the pressure drop and heat transfer coefficient increase with reducing twist ratio, increasing depth ratio and reducing width ratio.

^{[25]}We demonstrated that the heat transfer coefficients of manipulated surfaces in the subcooled flow boiling state were almost doubled and that the critical heat flux (CHF) values were promoted by 80%–200% under the tested flow conditions compared with under smooth surface conditions, with the flow path pressure drop deteriorating by less than 12%, indicating better capacities of high heat flux removal and low flow path resistance than those of existing PFC cooling schemes.

^{[26]}A prototype has been designed, manufactured and integrated in a mechanically pumped loop in order to evaluate the evaporator efficiency in terms of heat transfer coefficient and induced pressure drop.

^{[27]}The effects of pin fin shape, pin fin orientation, and ratio of distance between pin and plate fin center to pin fin size (S/Dp or S/Wp) on the flow pattern and heat transfer coefficient (HTC), pressure drop (ΔP) and thermal performance are investigated.

^{[28]}For all the nanoparticle shapes and cross-sections, uniformity of temperature distribution (θ) and thermal resistance reduce, while the heat transfer coefficient, pressure drop, and pumping power increase by rising the Reynolds number.

^{[29]}The flow boiling, condensation, and visualization of this low GWP refrigerant were examined experimentally to measure the heat transfer coefficients and pressure drop of the refrigerant, and also to present a flow pattern map.

^{[30]}For the optimal design of a PCHE, a simplified model is applied to obtain the heat transfer coefficient and pressure drop.

^{[31]}Predictive methods for the pressure drop and heat transfer coefficient from common correlations are also compared to the present experimental data, acting as verification of the facility and methods used for the macroscale boiling flows investigated in this work.

^{[32]}Heat transfer coefficient, Nusselt number, pressure drop, friction factor, performance evaluation criterion and thermal performance factor are evaluated for different Reynolds numbers (90–450) or flow rate (0.

^{[33]}Based on results, usage of twisted tapes has a sharp impact on thermal and hydraulic characteristics of heat exchanger and leading to swirling motion, which improve the heat transfer coefficient and augment the pressure drop (ΔP).

^{[34]}The fractal tree-like network inserted in a heat sink to obtain an increased heat transfer coefficient and a lower pressure drop has been widely researched.

^{[35]}The numerical model has been validated by comparing the pressure drop and the heat transfer coefficient with the experimental published data.

^{[36]}The current paper investigates the nanofluid effects as a coolant on the velocity of bulk, pressure drop, heat transfer coefficient, power peaking factors, and minimum departure from nucleate boiling ratio in a NuScale reactor, a natural circulation pressurized water reactor (PWR).

^{[37]}Thermal performance parameters like Nusselt number (Nu), heat transfer coefficient (htc), pressure drop, and pumping power were optimized by using weighted grey relational grade, depending on the experiments designed using Taguchi's Experiment Design.

^{[38]}Four key challenges were identified: (1) the need for better understanding of the mechanisms governing surface-structure-enhanced flow boiling and their effect on heat transfer coefficient, critical heat flux, pressure drop, and flow stability, (2) the need for rigorous quantification of surface durability and manufacturing scalability, (3) the need to understand effects of using working fluids other than water including refrigerants, supercritical fluids, and other dielectric fluids, and (4) the need to establish thermal resistance limits dependent on liquid film thickness.

^{[39]}Heat transfer coefficient and pressure drop are compared between the fluids and tubes.

^{[40]}Performance of heat exchanger is evaluated by the value of heat transfer coefficients, Reynolds number, Nusselt number, temperature distribution along the length, residence time and pressure drop.

^{[41]}It complicates the selection of condensers and requires reliable correlations for estimation of heat transfer coefficients and pressure drop in the unit.

^{[42]}After validation with the experimental results, a transient numerical model (based on the volume of fluid approach) was developed to investigate the hydrothermal properties of condensing such as bubble dynamics, flow map transitions, transient interface shear force, and temperature on flow condensation performance in terms of heat transfer coefficient and pressure drop.

^{[43]}The results showed that, for the hydrophilic metal foam filled tubes, the heat transfer coefficient and pressure drop are decreased by 2%–18% and 4%–15%, respectively than those for the uncoated ones; for the hydrophobic metal foam filled tubes, both the heat transfer coefficient and pressure drop are larger than those for uncoated ones, and the increments in the heat transfer and pressure drop are 6%–30% and 8%–35%, respectively.

^{[44]}This optimization problem focuses to determine the five independent design variables to find out the optimal values of heat transfer coefficient ( $$\stackrel{\sim }{H}$$ ) and pressure drop