Correlations For Flow Boiling Heat Transfer Research Articles

Experimental study on single- to two-phase flow and heat transfer of water in a small tube

Experimental investigation on flow boiling heat transfer in a small tube under high system pressure has been conducted in this study. The test-section is constructed with a 316L stainless steel tube. The inner diameter and heated length of the test-section are 5 mm and 930 mm, respectively. The working fluid is deionized water. The operating conditions of the experiments are as follows, the mass flux from 548 to 978 kg/(m2·s), the wall heat flux from 136 to 238 kW/m2, and the system pressure from 1.0 to 2.9 MPa. The experimental results showed that the inlet subcooling mainly affects the onset of nucleate boiling, but its impact on the heat transfer coefficient at the same vapor quality is almost negligible. The heat transfer coefficient increases with the increase of mass flux and wall heat flux, especially in the region where xe < 0.02. The average heat transfer coefficient is higher under high system pressure owing to the variation of the thermophysical properties. Additionally, the existing flow and heat transfer correlations cannot predict the flow boiling heat transfer coefficient and frictional pressure drop in the experiments accurately enough. Therefore, the new flow and heat transfer correlations are developed based on the experimental data in this paper, and the mean absolute deviation of the flow boiling heat transfer correlation and frictional pressure drop correlation are 13.3% and 12.1%, respectively.

Numerical investigation and data-driven prediction of flow boiling heat transfer in manifold microchannels with slopes

The manifold microchannels (MMC) with high heat transfer coefficient and low pressure drop has received much attention. Flow boiling heat transfer inside MMC is promising for dissipating heat of high-power devices. In this study, flow boiling heat transfer inside MMC is further numerically studied with slopes added in the upstream and downstream corners of MMC. The results show that downstream slope leads to lower local temperature and thermal resistance by removing the upstream vapor more easily, and upstream slope leads to higher heat flux corresponding to the turning point in the flowing boiling curve by restraining the local high temperature at upstream corner. The combination of the upstream and downstream slopes can reduce the thermal resistance by 5.45% and increase the heat flux related to the turning point by 14.28% compared to the MMC without slopes. A new flow boiling heat transfer correlation considering the slopes is developed with prediction accuracy of mean absolute deviation (MAD) of about 0.05%. An artificial neural network (ANN) is further built to predict the vapor saturation inside the MMC based on the outside temperature at the MMC bottom surface, which presents high accuracy of 97.03%.

Study of flow pattern transition criterion and heat transfer characteristics in vertical rectangular narrow channel for steam heating

This study clarifies the heat transfer characteristics of flow boiling in a narrow vertical rectangular channel at each stage and optimizes the performance of a heat exchanger. The flow pattern and local heat transfer characteristics in a narrow vertical rectangular channel of steam heating with dimensions of 1400 × 250 × 2.75 mm (l × w × s) were experimentally investigated using deionized water as the working medium. Based on the visualization data, the mechanical model and empirical formulas in previous literature, a preliminary derivation of the flow pattern transition criterion for steam heating in a vertical rectangular narrow channel was obtained. The effects of the inlet temperature, mass flux, and heating power on the local heat transfer characteristics were analyzed in conjunction with the flow patterns. Based on the parametric analysis of the experimental data, a new flow boiling heat transfer correlation formula was obtained and applied to the experimental conditions. The results showed that an increase in the inlet temperature had a positive effect on the nucleate boiling section, whereas the effect on the local heat transfer coefficient was minimal after entering the churn flow phases. The increase in mass flux decreased the local heat transfer coefficient in the nuclear state boiling stage and enhanced the local heat transfer coefficient in the evaporation zone of the liquid film flow. The peak of the local heat transfer coefficient tended to shift to the left as the heating power increased. The proposed heat transfer correlation equation could well predict the local heat transfer coefficient of flow boiling in a vertical rectangular narrow channel heated by steam under these experimental conditions.

A Comparative Analysis of Two-Phase Flow Boiling Heat Transfer Coefficient and Correlations for Hydrocarbons and Ethanol

This study will present a comprehensive review of the two-phase flow boiling heat transfer coefficient of hydrocarbons such as propane (R-290), butane (R-600), iso-butane (R-600a), and ethanol at various experimental conditions. Studying the multiphase flow heat transfer coefficient is crucial for many types of heat transfer equipment to achieve higher efficiency for more compact design and cost reduction. One reason we chose hydrocarbons as refrigerants in this study is that they are of an ozone depletion potential equal to zero (ODP = 0) and a deficient level of direct global warming potential (GWP = 3). Moreover, hydrocarbons’ thermodynamic and thermophysical characteristics qualify them to be a strong candidate for more heat transfer applications, initially, by constructing a database for the working fluids using multiple existing experimental work. The current data that this study have collected for the flow boiling spans a wide range of parameters, such as mass flux, heat flux, operating pressure, saturation temperature, etc. Furthermore, by comparing the experimental multiphase heat transfer coefficient database with the anticipated values of each correlation, the prediction performance of 26 correlations found in the literature was assessed. This study allows the best prediction method to be selected based on the minimum deviation of predicted results from the experimental database provided based on the mean absolute error (MAE) calculated from the assessed correlations. The conclusions of such a study can also be helpful for developing more accurate correlation methods for these fluids and improving the prediction of their flow boiling characteristics.

Evaluation of several liquid–vapor phase change models for numerical simulation of subcooled flow boiling

The phase change model has recently attracted attention for use in flow-boiling numerical simulation research. Comparison and evaluation of the calculation accuracies and resource consumptions of phase change models are essential for developing an efficient and high-precision phase change model. In this study, the Dong and Chen models, were added to the FLUENT software as two new models by introducing a unique user-defined function (UDF). The two unique models and the Lee model served as the foundation for numerical research, and the values of dependabilities and properties for flow and heat transmission predicted by these models were compared. Visual studies and flow-boiling heat transfer correlations were used to validate the results. The results reveal that the Chen model, which considers the active nucleation density site of bubbles, has a significant advantage over the other two models in terms of predicting flow characteristics. The Lee and Dong models are better suited for forecasting the changing tendency of the heat transfer coefficient, whereas the values obtained with the Chen model are closer to the reference values for the Liu–Winterton correlation. Besides, the two novel models also have higher computational costs.

Saturated/subcooled flow boiling heat transfer inside micro/mini-channels: A new prediction correlation and experiment evaluation

In this study, a new general heat transfer correlation was developed for predicting the saturated/subcooled flow boiling heat transfer coefficient in micro/mini-channels. The collected database included 4250 data points, which covered eleven different working fluids. These included deionized water, new electronic fluorinated solutions, and refrigerants, among others. The temperature range of the experimental operation was from 0 to 100 °C with a saturated pressure of 101 to 775 kPa. The hydraulic diameter of micro/mini-channels varied from 0.1 to 3 mm, and the liquid sub-cooling was between 0 and 80 K. The database included various operation conditions, such as mass flux, heat flux, vapor quality, and reduced pressure. The liquid and vapor Reynolds numbers were calculated based on the hydraulic diameter. Six existing flow boiling heat transfer correlations were employed to evaluate the present data points in micro/mini-channels. However, it was observed that these correlations were unable to predict the present data points accurately due to high liquid sub-cooling and heat flux. Therefore, a new prediction correlation based on the present database was developed by dividing flow boiling into three stages, including subcooled boiling, developed nucleate boiling and nucleate boiling deterioration. This new prediction model can predict more than 80% of data points within ±30% error band.

Deep learning-based assessment of saturated flow boiling heat transfer and two-phase pressure drop for evaporating flow

This work proposes new correlations as well as deep learning based modeling of saturated flow boiling heat transfer and two-phase pressure drops for evaporating flow. First, existing saturation flow boiling heat transfer correlations are compared to experimental database (2,500 data points) of numerous refrigerants for tube diameters ranging from 1 to 7 mm. The newly developed correlation for heat transfer outperformed the existing correlations resulting in an MAE =11.28%. For two-phase pressure drop of the evaporating flow, 1,954 measurement data points of 7 refrigerants were used, for the experimental tube diameter ranged from 0.509 to 14 mm. The newly developed correlation for pressure drop outperformed the existing correlations resulting in an MAE =19.07%. An optimal deep learning model (DL) was developed that further improved the accuracy of the prediction in terms of both heat transfer and pressure drop (R2=0.984 and MAE=4.5 % in terms of heat transfer and R2=0.994 and MAE=7.39 % in terms of two-phase pressure drop). The proposed correlations and deep learning models significantly improve microchannel prediction in terms of heat transfer and two phase pressure drop. Besides, explainable artificial intelligence highlights the dependence and interaction between various features affecting the heat transfer and pressure drop.

A novel integrated PDB-FDB model for the prediction of flow boiling heat transfer under high sub-cooling and very high heat flux conditions

Although numerous studies on subcooled flow boiling heat transfer have been conducted, those evaluating very high heat fluxes of several MW/m2 under one-side heating conditions are limited. In this study, the heat transfer characteristics of a circular smooth channel are evaluated under one-sided heating conditions with a high heat flux of up to 11.82 MW/m2. An experiment to measure the heat transfer (including boiling performance) from single-phase to critical heat flux (CHF) under an inlet pressure of 0.1–1 MPa, mass flux of 2000–6000 kg/m2s, and inlet bulk temperature conditions of 30–140 °C is conducted. The boiling regime is analyzed by dividing it into a partially developed nucleate boiling (PDB) regime and fully developed nucleate boiling (FDB) regime, using the onset of the nucleate boiling (ONB) point and onset of the fully developed nucleate boiling (OFDB) point. A total of 15 existing subcooled flow boiling heat transfer correlations for the PDB and FDB regimes are evaluated with the experimental results. In the PDB regime, the Liu and Winterton correlation reveal good predictability within 11%. However, all the evaluated existing correlations of the FDB regime exhibit high error rates. In this study, a new FDB correlation is developed by considering the agitation heat flux (an expected heat transfer characteristic in the FDB regime) in the Liu and Winterton correlation with Python code and the AI regression method. An evaluation of the developed correlation with the data of other previous studies, such as those of Araki et al. and Jianguo Yan et al. reveals that the newly proposed correlation can predict the FDB heat transfer under conditions of higher pressure (approximately 5 MPa) and higher flow rate (approximately 10,000 kg/m2s) with a low error rate of 17%.

Investigation of quench flow boiling heat transfer correlations for liquid oxygen feed line chill-down with outlet contraction

Cryogenic feed lines used for ground-based liquid transfer, thermal management in space flight, as well as the one with an injector at the outlet used for supplying propellants to the cryogenic engine combustion chamber, undergo an initial transient cool-down operation before vapor free liquid supply can be established through them. Accurate prediction of the thermal and hydraulic transients during this period has critical importance in the safe operation and efficient utilization of the cryogen. In the present work, a one-dimensional non-homogeneous two-phase model is used for simulating the chill-down operation in feed lines with and without outlet contraction. For transport feed lines without outlet constriction, the obtained transient wall temperature profiles indicate good prediction when the heat transfer correlations proposed based on recent chill-down experiments are employed as constitutive relations. Subsequently, the numerical model is applied for predicting the wall temperature transients during outlet contracted LOX feed line chill-down. It was noted that built-in heat transfer correlations in thermal–hydraulic code SINDA/FLUINT need revision, especially for rewetting point and heat transfer correlation during post rewetting regimes, for accurate thermal transient predictions during end constrained feed line chill-down. Hence, recent chill-down correlations reported in the literature and the correlations employed in previous chill-down numerical models are tested for their applicability. The recent cryogenic chill-down correlations reported in the literature performed well when applied within the correlation range. However, these correlations over predict the heat transfer at a very high mass flux (order of 3412 kg/m2 s). Hence, modified correlations are proposed for film and nucleate boiling heat transfer coefficients and rewetting temperature.

Numerical investigation of flow boiling heat transfer in manifold microchannels

The manifold microchannel (MMC) has drawn much attention due to its excellent convective heat transfer performance. Flow boiling in MMC can reach high heat transfer coefficient, however the research of which is rare in the literature. In this study, transient subcooling flow boiling heat transfer in MMC is numerically studied by a phase change model that renders the phase interfacial temperature converged to the saturation temperature. Effects of heat flux, subcooling, bottom channel height, and outlet/inlet width ratio are investigated in terms of vapor dynamic behaviors, thermal resistance, heat flux with the lowest thermal resistance and pressure drop. A lower subcooling promotes the occurrence of nucleate boiling and leads to lower thermal resistance, however the thermal resistance starts to rise earlier. In addition, too high bottom channel height deteriorates the convective heat transfer while too low bottom channel height leads to worse heat transfer at the upstream corner, and thus there exists an optimal channel height. Moreover, there also exists an optimal outlet/inlet width ratio which avoids the local worse heat transfer at upstream corner or vapor blockage in the outlet channel. Based on the results in the present study as well as in the literature, a new flow-boiling heat transfer correlation is developed for nucleate boiling in MMC. The new correlation agrees well with existing results, with mean absolute deviation (MAD) about 7.87%, much lower than MAD of 200% obtained by existing correlations. The present work is helpful for understanding flow boiling processes and providing flow-boiling heat transfer correlations in MMC.

Novel Saturated Flow Boiling Correlations for R600a and R717 Refrigerants

This research study provides a detailed analysis of the two-phase flow boiling heat transfer coefficients of R600a and R717. In addition, it proposes novel saturated flow boiling heat transfer correlations for these two refrigerants. In this context, 1306 experimental data points for R600a and 885 data samples for R717 are extracted from the literature works to develop new flow boiling models. Two different correlations are constructed under different forms of baseline frameworks for each refrigerant. The proposed flow boiling model for R600a utilizes the dimensionless numbers and operational parameters of the best performing literature correlations for this refrigerant while the model developed for R717 takes the advantage of piecewise continuous correlation form which successfully trace the tendencies of heat transfer coefficient with varying vapor qualities. It is found that the new model for R600a has a mean absolute error of 12.4% and mean relative error of 0.1, predicting 78.5% of the entire database within ±20.0% error band whereas the proposed correlation for R717 has an absolute error value of 17.3% having 65.3% of the data within ±20.0% error band, which are much better and accurate estimations compared to those obtained by the existing flow boiling models for R717 refrigerant.

A New Saturated Two-Phase Flow Boiling Correlation Based on Propane (R290) Data

There are plenty of literature research studies investigating two-phase heat transfer characteristics of propane under varying operational conditions. Based on the collected data retrieved from the experimental measurements, several flow boiling heat transfer correlations have been proposed up to now. However, the prediction accuracy of the proposed correlations for propane refrigerant is still in question as most of the correlation is developed for their measurements or derived for a limited range of operational conditions. To conquer this drawback, this study proposes a new flow boiling heat transfer model for smooth tubes based on a propane experimental database compiled of 2179 points obtained from different eighteen laboratories around the world. Operational conditions of the database cover mass fluxes between 50 and 600 kg/m2s, saturation temperatures between − 35.0 and 43.0 °C, heat fluxes between 2.5 and 227.0 kW/m2, hydraulic diameters between 0.3 and 7.7 mm, and thermodynamic qualities 0.01 to 0.99. Estimations performed by the new flow boiling model have been compared to those obtained by the literature correlations, and comparative results indicate that the proposed model surpasses the existing flow boiling in terms of prediction accuracy with a mean absolute error of 19.1% and mean relative error of 1.7%.

Heat-transfer characteristics of screw tube in one-side high heat load condition for fusion reactor divertor application

In this study, the heat transfer characteristics of one-side heated screw tubes were analyzed using subcooled flow boiling experiments. The experiments were performed until the critical heat flux was reached, while the applied heat flux was gradually increased. Subsequently, the boiling curves derived from the experimental results were divided into partial nucleate boiling (PDB) and fully developed nucleate boiling (FDB) regimes. As the flow rate increases, the forced convective heat transfer is enhanced, improving the single-phase heat transfer performance. However, as the FDB region is approached, most of the heat transfer proceeds via nucleate boiling heat transfer, so the heat transfer coefficient curve converges into the same straight line. The same trend was observed when analyzing the effect of the degree of subcooling. However, as the system pressure increased, and the liquid surface tension and latent heat decreased, a faster transition was observed from the single-phase regime to the PDB regime. From evaluating the prediction performance of the existing subcooled flow boiling heat transfer correlations, among the PDB regime; Liu and Winterton correlation, a kind of Chen-type correlation, showed the highest accuracy with mean absolute error (MAE) of 13.62% and root mean square error (RMSE) of 16.13%. However, most of the FDB correlations did not accurately predict the heat transfer performance of the one-side heated screw tube under a high heat flux load of several MW/m2. Therefore, a new screw tube FDB correlation was developed using Python code combined with artificial intelligence technology. The authors believe that the proposed correlation will be useful for not only predicting the heat transfer performance in the FDB region, but also establishing an operating map of the screw tube in the future.

Experimental study of hypervapotron channel with square fin structure for divertor cooling by one-side, electric joule heating system

The lack of cooling capacity to maintain the thermal steady state of the divertor is becoming a severe engineering problem in preparation for DEMO fusion reactor. But, there is not much literature comparing with the existing sub-cooled flow boilng heat transfer correlation and analyzing the Hypervapotron boiling curve. To simulate the fusion thermal condition, experimental loop that can withstand high temperature (150℃) and high pressure (20 bar) was constructed. And one-side electric joule heating system that can apply heat flux of up to 10.4 MW/m2 was developed. In addition, it was verified that stable operation is possible by confirming that the flow rate and the channel inlet temperature fluctuation rate are 1% or less, respectively. This experiment was carried out to evaluate the boiling heat transfer of Hypervapotron cooling channel at 10 bar, 40 ∼ 80 subcooling, 0.108 ∼ 0.284 kg /s and maximum effective heat flux of 6.87 MW/m2. Among the sub-cooled flow boiling heat transfer correlations, Thom correlation (1965), Jens & Lottes correlation (1951), and Aaladiev correlation (1957) differed significantly from the experimental data. But Shah 1977 (error rate: 4.75 %) and Kandlikar 1998 (error rate: 16.57 %) correlations were well predicted.

Two-phase flow boiling in a microfluidic channel at high mass flux

We report the experimental investigations of two-phase flow boiling heat transfer characteristics of a refrigerant in a microfluidic channel at a high mass flux (more than 1000 kg/m2 s). We investigate the heat transfer coefficients at a heat flux range of 7.63 kW/m2–49.46 kW/m2, mass flux range of 600 kg/m2 s–1400 kg/m2 s (high mass flux), and saturation temperature range of 23 °C–31 °C. We propose the new two-phase flow boiling heat transfer correlation of a refrigerant, which is used as the working fluid for the present experiments, at the microfluidic scale. We experimentally establish the functional relationship of two-phase flow boiling heat transfer correlation of the refrigerant during flow boiling in a rectangular microchannel with the Reynolds number, the boiling number, and the Weber number. We believe that the inferences of this study may provide a design basis for the micro-heat exchanger, typically used for thermal management in electronic devices, micro-electro-mechanical systems, and electric vehicle battery cooling system.

Experimental investigation on flow boiling characteristics of radial expanding minichannel heat sinks applied for two-phase flow inlet

Generally, two-phase (TP) flow inlet condition is not allowed for conventional microchannel heat exchangers, and a certain subcooled degree of liquid is strictly required to guarantee the efficient operation of system. To solve multi-heat sources cooling issue, a type of circular radial expanding minichannels heat sink (REMHS) utilizing flow boiling of deionized water is proposed in present work. Flow boiling heat transfer of REMHS is investigated with the inlet vapor mass qualities in the range of 0.01–0.53. Under TP flow inlet, slug-annular and annular flows are the main flow patterns observed in REMHS in this work, where the low-medium mass flux (22–132 kg/m2s) and medium-high heat flux (33.1–176.4 kW/m2) conditions are applied. The experimental results illustrate that the proposed REMHS under TP flow inlet maintains a stable and high flow boiling heat transfer performance without occurring heat deterioration. When xin increases from 0.04 to 0.53, the maximum local heat transfer coefficient increases by 22% from 42.5 to 51.9 kW/m2K. The flow distribution among the expanding channel array is relatively uniform and the heat transfer capability in the REMHS displays a good symmetry under TP flow inlet. The maximum discrepancy in heat transfer coefficient is below 19% within our experimental range. Six classic flow boiling heat transfer correlations are compared with the experimental results, and Li & Wu's correlation gives a good prediction on all the measured data with MAE of 21.1%. Besides, the thermal independence of REMHS connected in series is also examined, and the mutual interaction in heat transfer between the REMHS in series is trivial, the proposed REMHS is expected to be applied to multi-heat source cooling.

Operational behavior and heat transfer in a thermosiphon desorber at sub-atmospheric pressure. Part I: The model

The thermosiphon desorber or bubble pump is advantageous in absorption cooling devices, since the processes of refrigerant desorption and solution pumping is combined in one hermetical unit. This supersedes the necessity of a mechanical solution pump. In the application with NH3/H2O the thermosiphon desorber typically operates at a pressure of around 15 bar with a liquid vapor density ratio in the range of 102, which is in a well-known regime of two phase flow. Nevertheless, for the application of thermosiphon desorbers in H2O/LiBr absorption chillers, which are commonly operated at a pressure below 0.1 bar with the liquid vapor density ratio in the range of 104, there is a lack of heat transfer correlations for two-phase flow.First attempts to fill this gap of flow boiling heat transfer correlations in the thermosiphon desorber at sub-atmospheric pressures is presented in this paper. A model is formed by solving simultaneously the mass, energy, and momentum equations. The well-known correlations for predicting single-phase and two-phase flow heat transfer coefficient and frictional pressure drop have been reviewed to find a possibility for applying them to the thermosiphon desorber. The mass flow rate and heat transfer behavior with the different flow length of the riser tube and with changing the pressure has been theoretically studied in the model. For verification, the model has been compared to experimental data using pure water. This will be presented in the second part of the paper.

Boiling Heat Transfer Characteristics for Methane, Ethane and Their Binary Mixtures

Methane (R50) and ethane (R170) are the dominated components of natural gas and the important components in mixture refrigerants for the mixture Joule–Thomson refrigeration cycle. In this article, experimental investigations on nucleate pool boiling and flow boiling heat transfer characteristics of R50, R170, and their binary mixtures are presented. The effects of saturation pressure, heat flux, mass flux, concentration, and vapor quality on heat transfer coefficients are analyzed and discussed. Firstly, the pool boiling heat transfer data were compared with six well-known correlations. Labuntsov correlation shows the best agreement with a mean absolute relative deviation (MARD) of 11.3%. Secondly, a new flow boiling heat transfer correlation for pure fluids was proposed based on the asymptotic addition of forced convection and pool boiling. The modified enhancement factor and suppression factor were developed to account for their relative contribution. In addition, in order to consider the mass transfer resistance of mixtures, a new mixture factor was deduced. The new flow boiling heat transfer correlations can well predict the experimental data with the MARD of 9.5% for pure fluids and 8.3% for mixtures.

Flow boiling heat transfer of R123/R134a mixture in a microchannel

The flow boiling heat transfer of R123/R134a non-azeotropic mixture has been experimentally studied in a single microchannel of 190 μm ID for various experimental conditions: mixture composition (R123 ratio: 0.250, 0.502, 0.746), mass velocity (G = 314–470 kg/m2 s), heat flux (q″ = 10–20 kW/m2) and vapor quality (x = 0.2–0.9). The wall temperature is measured by a thermometer attached to the wall of the microchannel. Fluid temperature is measured at the inlet and outlet of the microchannel. The heat transfer coefficient is calculated based on the temperature, pressure, and mass flow measurement. The results indicate that the heat transfer characteristics of the mixed refrigerant are a function of mixture composition. The heat transfer for R123 mole fractions of 0.502 and 0.746 show good agreement with those resulting from the heat transfer mechanism of thin film liquid evaporation as pure R123. On the other hand, the heat transfer characteristics for R123 mole fraction of 0.250 indicates a heat transfer mechanism of nucleate boiling followed by two-phase forced convection of pure R134a. The criterion for the heat transfer mechanism concerning the flow boiling of mixed refrigerants in microchannels is determined by the presence of nucleate boiling at low vapor quality, which is identical to the criterion for pure refrigerants. The criterion of the heat transfer mechanism for mixed refrigerants is verified by the comparison with experimental results. Finally, the flow boiling heat transfer correlation for a mixed refrigerant in microchannels is developed from that for pure refrigerant using a correction reflecting the mass transfer effect in the mixed refrigerant. The new heat transfer correlation makes good predictions for experimental data. The new correlations can be applied to refrigerants which have similar thermophysical properties with R134a or R123.

Experimental study on flow boiling heat transfer of a new azeotropic mixture of R1234ze(E)/R600a in a horizontal tube

Recently, considerable attention has been given to new environment-friendly refrigerant mixtures for applications such as heat pumps and air conditioners. This study presents flow boiling heat transfer characteristics of environment-friendly refrigerant mixture of R1234ze(E)/R600a (0.148/0.852, 0.194/0.806, 0.371/0.629, 0.623/0.377 and 0.797/0.203 by mole fraction) in a smooth horizontal tube with an inner diameter of 6 mm. The experiments were conducted at saturation pressures from 0.215 to 0.415 MPa, mass fluxes from 67 to 194 kg m−2 s−1 and heat fluxes from 10.6 to 74.8 kW m−2. The influences of concentration, saturation pressure, mass flux and heat flux on heat transfer were analyzed and discussed. Furthermore, the experimental data were also compared with nine well-known flow boiling heat transfer correlations. The results indicated that correlation of Liu and Winterton (1991), which is the correlation for pure fluids, gives the best fit to the experimental data with a mean relative deviation of 18.2%. Finally, a new heat transfer correlation based on power-additive model was proposed and two suppression factors Smix and Fmix were introduced into the new correlation by taking account of mass transfer resistance. The new correlation makes great progress in the prediction accuracy with a mean relative deviation of 6.4%.