Effective Area Ratio Research Articles

Diffusion-Dominated Proxy Model for Solvent Injection in Ultratight Oil Reservoirs

SummaryEnhanced oil recovery (EOR) by solvent injection offers significant potential to increase recovery from shale oil reservoirs, which is typically between 3 and 7% original oil in place (OOIP). The rather sparse literature on this topic typically models these tight reservoirs on the basis of conventional-reservoir processes and mechanisms, such as by convective transport using Darcy's law, even though there is little physical justification for this treatment. The literature also downplays the importance of the soaking period in huff ’n’ puff.In this paper, we propose, for the first time, a more physically realistic recovery mechanism based on solely diffusion-dominated transport. We develop a diffusion-dominated proxy model assuming first-contact miscibility (FCM) to provide rapid estimates of oil recovery for both primary production and the solvent huff ’n’ soak ’n’ puff (HSP) process in ultratight oil reservoirs. Simplified proxy models are developed to represent the major features of the fracture network.The key results show that diffusion-transport considered solely can reproduce the primary-production period within the Eagle Ford Shale and can model the HSP process well, without the need to use Darcy's law. The minimum miscibility pressure (MMP) concept is not important for ultratight shales where diffusion dominates because MMP is based on advection-dominated conditions. The mechanism for recovery is based solely on density and concentration gradients. Primary production is modeled as a self-diffusion process, whereas the HSP process is modeled as a counter-diffusion process. Incremental recoveries by HSP are several times greater than primary-production recoveries, showing significant promise in increasing oil recoveries. We calculate ultimate recoveries for both primary production and for the HSP process, and show that methane injection is preferred over carbon dioxide injection. We also show that the proxy model, to be accurate, must match the total matrix-contact area and the ratio of effective area to total contact area with time. These two parameters should be maximized for best recovery.

Experimental research on propulsive performance of the pulse detonation rocket engine with a fluidic nozzle

To explore an effective way for the nozzle design of a pulse detonation rocket engine (PDRE), theoretical and experimental researches have been carried out. The exhaust process and optimal converging/diverging area ratios of a nozzle were theoretically analyzed. Pressure and velocity fluctuations of the exhaust flow were considered to be the major issues. A fluidic solution which employs nitrogen flows in the nozzle throat and divergent section has been tested. The fluidic nozzle is able to adjust the effective area ratios according to the incoming flow. The effective convergent area ratio varied from 2.0 to 2.2, and the divergent one varied from 5.0 to 1.8. It is proved that the fluidic nozzle effectively improved the propulsive performance of the engine. A maximum average thrust increase of 137.8% was obtained in proper conditions.

A Simulation Study for the Design of Membrane Restrictor in an Opposed-Pad Hydrostatic Bearing to Achieve High Static Stiffness

The effects of a membrane restrictor’s design parameters on the performance of a hydrostatic opposed-pad bearing are presented in this article. Compared to the single-pad bearing, the opposed-pad bearing can perform much better in terms of static stiffness over a wider load range. It is also found that, for small bearing eccentricity, the optimal design restriction ratio of 0.25 still results in high bearing stiffness even if the dimensionless stiffness of membrane is not the optimal value of 1.33. Furthermore, decreasing the ratio of the upper effective area to the lower effective area generally increases the applicable working range of the bearing. Additionally, for high loading demands, the chance for further improvement of bearing performance by employing different design parameter for each pad is examined. Finally, a design procedure for designing the membrane restrictor for an opposed-pad bearing to achieve high static stiffness is given.

Evaluation for VOF Simulation of Flow Field in Asphalt Foaming Chamber Based on Volume Fraction

Abstract Asphalt with high viscosity, air, and water constitutes multi-phase turbulent flow accompanied by complex dynamic phenomena such as heat transfer and phase transition in the foaming chamber during the asphalt foaming process. The foaming process is difficult to fully describe by mathematical model. In order to establish the correspondence between the approximate simulation flow field in the foaming chamber and the physical experiment, it is necessary to propose a reasonable evaluation method for the flow field simulation in the foaming chamber. Approximate numerical expression of asphalt foaming process is established by the volume of fluid (VOF) multiphase flow calculation method combined with self-defined phase and mass transfer functions. Based on the principle of asphalt foaming, effective foaming area is defined as the area where temperature is ≥100°C, volume fraction of asphalt is ≥0.5, and volume fraction of water vapor is between 0.1 and 0.4. The ratio of the effective foaming area to the total flow field is taken as the evaluation index. The proportion of effective foaming area obtained by asphalt foaming numerical simulation is compared with the expansion rate and half-life obtained by asphalt foaming experiments with three foaming chambers of different sizes. The comparison shows that ratio of effective foaming area has the same tendency as expansion rate and half-life. And the simulation evaluation index is verified. Suggestions are put forward on the structure design of asphalt foaming chamber based on the distribution of effective foaming area. It shows that this method achieves rapid theoretical evaluation of foaming chamber structure and could be used for the optimal design of foaming chamber.

NEW VARIETIES AND CULTURES FOR CULTIVATION ON HYDROPONIC RACKING INSTALLATIONS IN MODERN GREENHOUSES

Vegetables are vital foods that determine the health and longevity of the population. Development of greenhouse vegetable production, introduction of new technology solves the problem of overcoming the seasonality in vegetable consumption. According to projections The Russian Ministry of Agriculture, the area of the greenhouses to the 2020 will be 4 700 hectares and production of greenhouse vegetables will increase to 1,7 million tonnes per year. Thus, The State believes the real increase area of greenhouses and gross harvest of vegetables protected soil in more than 3 times. Many greenhouses began to transfer cultivation of vegetables with little ground volume technology, modern facilities, equipped with one seedlings shelving units are a variety a hydroponic cultivation methods. Use shelving with Jacob’s platform allows to increase the utilization ratio of effective area of greenhouse to 0,85 and considerably facilitates the hard work of greenhouse working. Modern technology the growing seedlings on tables significantly different from the traditional technology, allowing us to get planting material of better quality during short period after sowing. New conveyor hydroponic technologies allow us to grow ecologically safe products, reducing its cost. These technologies require new varieties and hybrids of vegetable crops high intensification of production. Along with the growth of vegetable yields, which will combined with a reduction in labor costs per unit of output and lower its cost, particular attention must be paid their biological value.

Analysis and experimental verification of weight saving with trapezoidal base heat sink

A quick weight saving methodology with trapezoidal base heat sink applicable for electronic cooling application is studied analytically, numerically, and experimentally. The conventional heat sink with rectangular base can be modified into trapezoidal base for material saving. A differential equation capable of describing the temperature distribution of the trapezoidal base is derived and its closed-form analytic expression is derived. It is found that three parameters rA (ratio of effective surface area to the base area), rd (ratio of chip lateral length to the base length) and h+ (modified convection heat transfer coefficient) play pivotal roles in balancing the material saving and the performance loss. When rd = 0.1, the material saving for rt = 0.6 is about 18%; while the corresponding performance loss is 2.93%. When rd = 0.2, the material saving for rt = 0.6 is about 16%; while the corresponding performance loss is 2.47%. The analytical results are verified with experiments with good agreement.

A DT fusion reactor design in field-reversed configuration using normal conductive coils

Assuming continued stability, favorable energy confinement time scaling, and an effective current drive and maintenance methods, a feasible DT fusion reactor design is proposed for field-reversed configuration (FRC) which uses normal conductive copper magnetic field coils at room temperature. The reactor has 3 GW fusion power, 1.5 MW m−2 neutron wall loading at the first wall, and thermal loading less than 1 MW m−2 at diverter plates. Plasma has an almost straight cylindrical shape of 40 m in length and 8.6 m in diameter. FRC can obtain very high beta (over 0.7 in average) and the magnetic field strength of the reactor will be 1.215 T, which can be produced by normal conductive coils having 70 m in length, 17.6 m in diameter, and 1.5 m in thickness with 0.6 effective conductive area ratio. Its Ohmic power loss is ~74 MW, which is less than 10% of the expected electric power output. A scenario to reach ignition from the initial formation is considered. At first, two FRCs are formed at the both ends of the reactor by fast theta-pinch with a negative bias magnetic field 6 m in length and 0.5 m in diameter. The FRCs are accelerated up to 250 km s−1 by the gradient of magnetic field strength towards the center of the burning region, collide with each other, and form a single large FRC. Their kinetic energy is converted to thermal energy, and the merged FRC is 10 m in length and 1.8 m in diameter. This FRC plasma is brought to ignition by intensive neutral beam injection (NBI) heating and particle supply. Given 200 s heating duration, the maximum NBI power is ~250 MW before alpha particle heating becomes significant. After ignition, NBI heating is not required, but there is a possibility that some part of equilibrium current must be supplied by the NBI in the MeV region.

Six Degrees of Freedom Wide-Range Ubiquitous IPT for IoT by DQ Magnetic Field

Direct and quadrature (DQ) rotating magnetic-field-based transmitting (Tx) coils for wireless charging of multiple internet of things (IoT), which are broadly distributed over three-dimensional (3D) spaces, are newly proposed in this paper. The proposed Tx coils provide a uniformly distributed DQ magnetic field environment so that numerous IoT, such as active radio frequency identification (RFID) tag, electric shelf label (ESL), appliances, and various sensors connected to internet, are charged with 3-D omnidirectional wireless charging. By virtue of the generated DQ magnetic field, six degrees of freedom (6-DoF), regardless of their three-axes positions and directions, are achieved by the proposed Tx coils with plane receiving (Rx) coils, which is essential for the proposed ubiquitous wireless power environment. Therefore, the proposed wide-range ubiquitous inductive power transfer (IPT) is highly recommended for adoption in practical applications, where volumetric structures with large size of core are not allowed. The optimum distance between the DQ lines of the proposed Tx coils $d_{w}$ was found by magnetic field analysis to deliver maximum magnetic field $B_{t}$ at a target distance of $z_{{1}}$ . To generate DQ currents and guarantee zero-voltage-switching operation of the main switches, detailed static analysis of the proposed DQ Class D inverter based on an imaginary gyrator model is presented. The effective area ratio of an Rx coil having a ferrite core is derived and experimentally found in this evenly distributed magnetic field condition. 1:20 and 1:1 scaled-prototypes for $d_{l}\,= \,{\text{10}}\;\text{m}$ and 5 m DQ line cases, respectively, were installed on the ceiling and experimentally verified for the uniformity of magnetic field and the highest wireless power delivery freedom. Experimental results showed that the proposed IPT has 78% of uniformity for magnetic field and Rx coils are freely charged with a 6-DoF characteristic. Two hundred of Rx coils, which are arbitrarily distributed over 3-D space, can be simultaneously charged with 16.2 W of total received load power and 9.3% of power efficiency.

Bandwidth density as a figure of merit for few-mode multi-core fibers.

We investigated the relationships between the capacity limit and various figures of merit (spatial channel density, aggregate effective area ratio to cladding area, and bandwidth density) of few-mode multi-core fibers (FM-MCFs) where the modes in each core are weakly coupled. The capacity limit was estimated based on the Gaussian noise model for nonlinear impairment of single-mode fibers by neglecting crosstalk and intermodal nonlinear effects for simplicity; therefore, the estimated capacity can be the upper bound of the weakly-coupled FM-MCF capacity. When we take account of the transmission wavelength band of the FM-MCFs and the wavelength band where efficient amplification is available, the bandwidth density had a good correlation to the estimated capacity, but the spatial channel density and the aggregate effective area ratio often overestimate the FM-MCF capacity. Thus, we propose the bandwidth density for the figure of merit of FM-MCFs rather than the spatial channel density or the aggregate effective area ratio. We also investigated the relationship between the bandwidth density and fiber design, and found that the supporting transmission bandwidth and the core count are the dominant factors for the bandwidth density, and the mode count per core has a small impact for the bandwidth density, when the core Δ is fixed.

Effects of the window openings on the micro-environmental condition in a school bus

School bus is an important micro-environment for children's health because the level of in-cabin air pollution can increase due to its own exhaust in addition to on-road traffic emissions. However, it has been challenging to understand the in-cabin air quality that is associated with complex airflow patterns inside and outside a school bus. This study conducted Computational Fluid Dynamics (CFD) modeling analyses to determine the effects of window openings on the self-pollution for a school bus. Infiltration through the window gaps is modeled by applying variable numbers of active computational cells as a function of the effective area ratio of the opening. The experimental data on ventilation rates from the literature was used to validate the model. Ultrafine particles (UFPs) and black carbon (BC) concentrations were monitored in “real world” field campaigns using school buses. This modeling study examined the airflow pattern inside the school bus under four different types of side-window openings at 20, 40, and 60 mph (i.e., a total of 12 cases). We found that opening the driver's window could allow the infiltration of exhaust through window/door gaps in the back of school bus; whereas, opening windows in the middle of the school bus could mitigate this phenomenon. We also found that an increased driving speed (from 20 mph to 60 mph) could result in a higher ventilation rate (up to 3.4 times) and lower mean age of air (down to 0.29 time) inside the bus.

Coupling of in-situ pervaporation for the enhanced esterification of propionic acid with isobutyl alcohol over cenosphere based catalyst

In the present work, pervaporation assisted esterification of propionic acid and isobutyl alcohol, to produce isobutyl propionate and water was investigated in an in-situ type pervaporation reactor. A commercial polymeric hydrophilic PVA-PES membrane was used to shift the conversion of equilibrium limited esterification reaction by the removal of water from the reaction mixture. Catalyst developed from cenosphere (waste material) was used in the study. The effects of process parameters viz; reaction temperature, catalyst loading, alcohol/acid molar ratio and a ratio of effective membrane area to initial reaction volume (S/V) were studied.Catalyst characterization elucidated that the catalyst exhibited significant silica content, surface acidity with a considerable surface area. The membrane showed a significant selectivity towards the water removal which subsequently enhanced the pervaporation performance. A substantial enhancement in the conversion of esterification reaction from 67% to 88% was observed by the incorporation of pervaporation at a temperature of 353K. The membrane and catalyst revealed a significant stability up to four and three reaction runs respectively. Results revealed that all process parameters linearly affected the conversion and permeate flux of pervaporation assisted esterification. The maximum esterification conversion was obtained to be 92% at a reaction temperature of 353K, catalyst loading of 20g/L, alcohol/acid molar ratio of 2.5 and S/V ratio of 19.63m−1.

Esterification of acrylic acid with ethanol using pervaporation membrane reactor

Esterification of acrylic acid with ethanol was carried out using an in-situ reactor with an integrated pervaporation assembly (IPAE) made of polyvinyl alcohol (PVA) membrane and was compared with a non-integrated (NIE) system. Effect of reaction temperature (T r ), catalyst loading (C C ), molar ratios of reactants (MR) and ratio of effective membrane area to unit volume of reaction mixture (S/V o ) on kinetics of esterification reaction were studied. Conversions achieved in IPAE were found to be distinctly higher than the NIE. The highest conversion of acrylic acid was obtained as 83.3% at T r =60 °C, M R =3 : 1, C C =2% and S/V o =14.1 m−1. Equilibrium conversion of acrylic acid in NIE was obtained as 55.1% at 60 °C, 1 : 1 in 7 h, while using IPAE conversion enhances to 67.6%. Esterification of acrylic acid and ethanol with presently studied operating parameters provides a new approach to existing literature reported esterification-pervaporation system.

Influence of Structural Parameters of Two-throat Nozzle Ejector on Performance of Two-phase Flow Ejector Refrigeration System

The expansion work can be recovered and the inlet pressure of the compressor can be increased by using the two-phase flow ejector, so as to reduce compressor power consumption and improve the system performance. In this paper, the experimental study on the performance of R134a two-phase flow ejector with two-throat nozzle refrigeration system is carried out. The influence of the structure parameters of the ejector on the performance of the ejector and the refrigeration system was discussed. The experimental results indicate that the smaller nozzle distance is beneficial to improve the performance of ejector. Under the condition of the condensing temperature of 40°C and the evaporation temperature of -10°C, the performance of the ejector and the ejector system is the best as the divergence angle of the first nozzle is 8°. The refrigeration capacity of the system can be adjusted by changing the position of the injection needle. As the effective area ratio of the nozzle throat is 90%, the performance of the system and the ejector can reach the maximum value.

English

This study aims to evaluate the production of biomass of different cattle manure, and biofertilizer concentrations. The experiment was conducted between April and June 2014 in a greenhouse at the seedling production nursery of the State University of Paraiba (UEPB), Catole do Rocha, Paraiba (PB) state. The experiment was completely randomized in a 5 x 2 factorial design corresponding to five levels of cattle manure (0, 20, 40, 60 and 80% of the substrate volume) in the absence, and the presence of a biofertilizer. The propagation material was giant yellow passion fruits with 95 to 100% of purity purchased in the local market. After 60 days, the following variables were evaluated: root dry matter (RDM), plant dry matter (PDM), root biomass (RB), shoot biomass (SB), plant biomass (PB), biomass percentage (BP), effective leaf area (ELA) and leaf area ratio (LAR). The interaction between cattle manure and fertilizer concentrations was significant for root dry matter, mass of total plant dry matter, root biomass, shoot biomass and total plant biomass. In turn, cattle manure affected significantly biomass percentage, effective leaf area and leaf area ratio. Cattle manure and biofertilizer make the production of yellow passion fruit seedlings feasible. Key words: Passiflora edulis Sims f. flavicarpa Degener., alternative sources, propagation, protected environment.

Estimation of Contraction Coefficient of Gorlin Equation for Assessment of Aortic Valve Area in Aortic Stenosis

Background: The Gorlin equation is the reference method for the assessment of aortic valve area in aortic stenosis and is calculated using a constant, called the coefficient of contraction, which is empirically assumed to be 1. This coefficient is the ratio of effective aortic area to anatomic aortic area, and a value of 1 indicates that both are the same. The purpose of this study was to estimate the actual coefficient of contraction in patients with aortic stenosis and to evaluate its impact on aortic area as calculated by the Gorlin equation. Methods: We studied 17 patients with moderate to severe aortic stenosis. Effective aortic area was calculated using the continuity equation. Anatomic aortic area was obtained by planimetry with transesophageal echocardiography. Aortic valve area by the Gorlin equation was calculated from echocardiography data. The coefficient of contraction was derived as above. Results: The coefficient of contraction was inversely related to the pressure recovery. Effective area was correlated with anatomic area (r = 0.86, P 2). Aortic area by the Gorlin equation was not correlated with anatomic area, but the correlation became significant when the Gorlin equation was corrected for coefficient of contraction and pressure recovery. Conclusions: Using a coefficient of contraction of 1 in the Gorlin equation gives a poor correlation with anatomic area. Using the calculated coefficient of contraction for each patient and the mean gradient for pressure recovery improves the correlation with anatomic area. These facts could be taken in account when Gorlin equation is considered as the reference method.

Echocardiograms Estimated the Severity of Aorticstenosis (AS) Accompanied with Tachycardiac Arrhythmia (AATA)

patients accompanied with tachycardiac arrhythmia (Frequent premature ventricular arrhythmia, supraventricular tachycardia,atrial fibrillation, etc), estimated the severity of aorticstenosis under transthoracic echocardiography (TTE), using the methods as below: continuous-wave (CW) Doppler echocardiography estimated aortic jet speed (VAV) and across valve mean pressure difference (△Pmean), Doppler echocardiography estimated the effective aortic valve area (AVAeffective) and velocity ratio (VR=VLVOT/VAV) by using the continuity equation, 2D echocardiography estimated aortic valve geometric area in anatomy (AVAanatomy). And compared the stability, accuracy and clinical value of these methods. This was a review of 11 AATA cases that were diagnosed in our institution between November 2016 and January 2017. At the condition of tachycardiac arrhythmia, estimating VAV, △Pmean, AVAeffective, VR and AVAanatomy under TTE. At the condition of normal arrhythmia under cardiopulmonary bypass during the surgery, estimating VAV, △Pmean, AVAeffective, VR and AVAanatomy once more under transesophageal echocardiography (TEE). And also, estimating AVAanatomy intraoperative exploration. In order to decrease the measurement error, we measured every values at lest three times and choose the mean value. Compared with the values estimated under normal arrhythmia, at the condition of AATA (with the severity of AS at moderately to severely), the value of VAV and △Pmean have differences (P < 0.05), easy to underestimate the severity of AS; the value of AVAeffective and VR have differences (P < 0.05), easy to overestimate the severity of AS; the value of AVAanatomy, which often greater than the value of AVAeffective, has no obvious difference and has good consistency with the geometric area of aortic measured intraoperative exploration. When estimating the severity of AS at the condition of AATA under TTE, the methods of assessment by Doppler echocardiography often instability, easy to underestimate or overestimate because of the affection of the ventricular rate. While the method of assessment by 2D echocardiography seemed to be less sensitive to the ventricular rate, so that could be a more reliable method in estimating the severity of AS at AATA and have clinical significance, although it has some differences with the value of AVAeffective.

Experimental study of heat transfer characteristics of high-velocity small slot jet impingement boiling on nanoscale modification surfaces

Jet impingement boiling is one of the most efficient methods to increase the critical heat flux. Through controlling surface chemical properties and topography, plain nickel foil surface, three kinds of plain nickel-based chemical treatment surfaces and four kinds of nickel-based electrochemical treatment surfaces with nanocone array structure were used in the jet impingement boiling experiments to investigate the quantitative effects and the effect mechanism of the surface characteristic parameters, including nanoscale roughness (Ra): solid–liquid contact angle (CA) and effective heat transfer area ratio (r: the ratio of the actual heat transfer area to its projected area) on the heat transfer coefficient (HTC) and the critical heat flux (CHF). It is revealed that: similar to the heat transfer in pool boiling, changing nanoscale Ra has little effect on the heat transfer characteristics; decreasing solid–liquid CA can enhance the HTC while worsen the CHF obviously; increasing r can intensify both the HTC and the CHF. Predictive correlations of the HTC and the CHF of jet impingement boiling which include the effects of surface characteristics are presented. The predictive correlations presented can be widely used in various conditions with different working fluids and heating surfaces.

Application of a mordenite membrane to the esterification of acetic acid and alcohol using sulfuric acid catalyst

The well acid-stable and hydrophilic mordenite membrane is applied as a “membrane extractor reactor” for the esterification of acetic acid and alcohol with the H2SO4 as catalyst. The mordenite membrane reactors are placed into the reaction mixtures and continuously remove water from the esterification mixture by pervaporation, which could greatly improve the alcohol conversions of esterification. Besides, the effects of the reaction conditions (such as temperature, molar ratio of acetic acid/alcohol, and catalyst loading) on the ethanol conversion are investigated in details. As the reactional temperature, the molar ratio of acetic acid/alcohol, the catalyst loading, and the ratio of effective membrane surface area to esterification mixture volume are 85 °C, 1.5, 0.05 wt% (0.005 mol/L), and 0.31 cm2/cm3, the ethanol and n-butanol conversions of esterifications are up to 98.13% and 98.73%, respectively. Even if the mordenite membrane is applied to pervaporation-esterification for 8 times (96 h), the mordenite membranes are still kept the typical diffraction peaks and morphology by XRD and SEM characterization, and the dehydration performance of the membrane for 90 wt% HAc/H2O mixture at 75 °C is almost the same as the as-synthesized mordenite membranes, and the flux and separation factor of the mordenite membrane after 8 times PV-esterification are 0.44 kg m−2 h−1 and 627.

ポーラス金属フィンの沸騰熱伝達率の予測法の精度検証

Porous metal fin was used as boiling heat transfer plate of phase change devices. The number of cells of the porous metal fin is 8 ppi, and the pore diameter of the porous metal fin is 3.1 mm. On the boiling heat transfer surfaces, the porous metal fin and the bass plate are brazed. Three samples of boiling heat transfer plates with the porous metal fin were made as prototype. Working fluids are HFE7000 and HFE7100 made by 3M. Predicting method of the boiling heat transfer coefficient was based on the expansion ratio of effective area to the flat plate and the correlation of that of Stephan's equation. The boiling heat transfer coefficient in the heat transfer plate with surface roughing process of concave can be put in order by ± 10 %.

Parametric optimization and performance analysis of ORC (organic Rankine cycle) for diesel engine waste heat recovery with a fin-and-tube evaporator

This paper presents the parametric optimization and performance analysis of ORC (organic Rankine cycle) system using GA (genetic algorithm) for recovering exhaust waste heat of a diesel engine. First, the effects of three key parameters, including evaporation pressure, superheat degree and condensation temperature on the system performances are conducted with POPA (net power output per unit heat transfer area) and EDR (exergy destruction rate) as objective functions. The optimal evaporation pressure, superheat degree and condensation temperature corresponding to the maximum POPA and the minimum EDR are provided under engine various operating conditions. Subsequently, as a key component of the ORC system, the performance of a fin-and-tube evaporator used in this ORC system is evaluated. The results show that the optimal evaporation pressures are mainly influenced by the engine operating conditions, whereas the superheat degree and the condensation temperature present a slight variation over the whole operating range. Furthermore, the PPTD (pinch point temperature difference) in the evaporator may occur at different positions with the variation of engine operating conditions. At engine maximum rated power point, the ORC system can achieve maximum POPA of 0.74 kW/m2, and the ratio of maximum effective heat transfer area to actual area of the evaporator is 69.19%.