Aerodynamic Transfer Research Articles

Comparison of Unsteady Low- and Mid-Fidelity Propeller Aerodynamic Methods for Whirl Flutter Applications

Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction.

Frequency-Domain Lifting-Line Aerodynamic Modelling for Wing Aeroelasticity

A frequency-domain lifting-line solution algorithm for the prediction of the unsteady aerodynamics of wings is presented. The Biot–Savart law is applied to determine the normalwash generated by the wake vorticity distribution, whereas steady and unsteady airfoil theories (Glauert’s and Theodorsen’s, respectively) are used to evaluate the sectional aerodynamic loads, namely the lift and pitching moment. The wake vorticity released at the trailing edge derives from the bound circulation through the Kutta condition and is convected downstream with the velocity of the undisturbed flow. The local bound circulation is obtained by the application of the Kutta–Joukowski theorem, extended to unsteady flows. Assuming a bending and torsion wing, this paper provides the aerodynamic matrix of the transfer functions, relating the generalised aerodynamic loads to the Lagrangian coordinates of the elastic deformation. Its rational approximation yields a reduced-order state-space aerodynamic model suitable for an aeroelastic stability analysis and control purposes. The numerical investigation examines the influence of both the wake shed/trailed vorticity modelling and different approximations of the Kutta–Joukowski theorem for unsteady flows on the aerodynamic transfer functions given by the developed frequency-domain lifting-line solver. The accuracy of the solver is assessed by comparison with the predictions obtained by a three-dimensional boundary-element-method solver for potential flows. It is shown that, at least for the frequency range considered, regardless of the approximation of the Kutta–Joukowski theorem applied, the formulation based on the Theodorsen theory provides predictions that are in very good agreement with the results from the boundary element method for a slender wing. This agreement worsens as the wing aspect ratio decreases. A lower level of accuracy is obtained by the application of the sectional loads given by the Glauert theory. In this case, the predictions are more sensitive to the approximation used to express the Kutta–Joukowski theorem for unsteady flows.

Robustness Analysis on the Aerothermal Performance of Turbine Blade Squealer Tip

Abstract An improved efficient uncertainty quantification (UQ) analysis framework is proposed by the combination of sparse polynomial chaos expansion (PCE) and universal Kriging (UK) metamodel to obtain the surrogate model (UK-PCE). Moreover, a challenging analytical test function and an engineering test are considered to investigate the response performance of UK-PCE method. The results show that the UK-PCE method reduces the computational cost by more than 70% in comparison to the typical PCE method. Then this method was applied to the UQ of the aerodynamic and heat transfer performance of GE-E3 rotor blade squealer tip. Additionally, a series of uncertainty quantities visualization methods based on the data mining method, parallel computing method, and Delaunay triangulation method is proposed to reveal more enlightening uncertainty phenomena in the actual operation. The results of UQ show that under the influence of uncertain inputs, the leakage flow rate and downstream entropy increase will be significantly increased. The statistical average of tip heat flux has increased by 8.56% relative to the design value, and the probability of it deviating from the design value by 10% is as high as 43.27%. In addition, the three-dimensional tip heat flux deviation distributions calculated by the proposed uncertainty quantities visualization method reveal a coupling of the hot corrosion and thermal fatigue of the squealer tip. It is also indicated that under the influence of the uncertain inputs, there is a marked increase in blade tip flux, and the blade tip flux deviation has been maintained at a high value, about 13.0%. The results of sensitivity analysis show that the largest contributor to the uncertainty of the blade tip aerodynamic performance is the tip clearance deviation and its variance index to the uncertainty of leakage flow rate and downstream entropy increase is as high as 88.21% and 62.63%. Therefore, the geometric accuracy of the tip clearance should be strictly ensured in the turbine blade assembly and marching process. The influence of the inlet total temperature deviation on the uncertainty of the heat transfer performance of the squealer tip must also be taken into account. So a satisfactory control system should be designed in the actual operation of the gas turbine to make sure that the fluctuation of inlet total temperature can be attenuated rapidly.

Efficient Uncertainty Quantification and Sensitivity Analysis on the Aerothermal Performance of Turbine Blade Squealer Tip

Abstract It is important to accurately estimate the impact of flow and geometric variations for engineering design and manufacture. In this paper, an efficient uncertainty quantification analysis framework based on the combination of Universal Kriging (UK) metamodels and sparse Polynomial Chaos Expansion (PCE) is proposed. A challenging analytical test function and an engineering test are considered to investigate the response performance of the UK-PCE method. Then, this method was applied to the uncertainty quantification on the aerodynamic and heat transfer performance of GE-E3 rotor blade squealer tip. Meanwhile, a global parameter sensitivity analysis using the Sobol Indice method is carried out to identify the key parameters for the aerothermal performance of the squealer tip. Wherein, the inlet total temperature is considered as flow condition uncertainty parameters and tip clearance and cavity depth are considered as geometrical uncertainty parameters. The results show that the UK-PCE method reduces the computational cost by more than 70% in comparison to the typical PCE method. Under the influence of the uncertain geometry and operating conditions, the heat flux of the squealer tip basically conforms to the normal distribution and the statistical mean value of it increased by 5.32% relative to the design value and the probability of it deviating from the design value by 5% is as high as 44.62%. The result of sensitivity analysis reveals that the uncertainty of the aerodynamic characteristics of the squealer tip is almost entirely caused by the tip clearance which accounts for 90.31% and 98.77% of the variance of the leakage flow rate and total pressure loss coefficient. And it is also a key variable for the uncertainty of the heat transfer performance considering that its variance indexes for tip heat flux and blade heat flux are 31.23% and 73.14%, respectively. Finally, the influence mechanisms of the uncertainty parameters on the aerothermal performance of the squealer tip are investigated by detailed flow and thermal field analysis.

Parametric Reduced-Order Modeling of Aeroelastic Systems

In this paper, two approaches for modeling parameter-dependent unsteady aerodynamic loads for control design purposes are presented. The approaches are based on parametric Loewner frameworks, namely, transfer matrix interpolation and global basis. Combined with postprocessing techniques, these frameworks generate highly accurate, reduced-order state-space models of aerodynamic loads. The approaches are computationally efficient since they can model the entire flight envelope while requiring only a single input set of aerodynamic transfer matrix data. Additionally, constant numerical settings can be used across wide ranges of the parameter values without loss of accuracy. The proposed approaches are applied to state-space modeling of a two-dimensional aeroelastic system. The evaluated accuracy and dynamic behavior of the model show excellent agreement with the reference frequency domain solutions for both approaches.

Impact of Rotor-Casing Effusion Cooling on Turbine Performance and Operating Point: An Experimental, Computational, and Theoretical Study

Abstract It is known that a secondary effect of rotor-casing effusion cooling is to modify and potentially spoil the rotor over-tip leakage flow. Studies have shown both positive and negative impacts on high-pressure (HP) stage aerodynamic performance and heat transfer, although there remains no consensus on whether the net effect is beneficial when both aerodynamic and thermal effects are accounted for simultaneously. An effect that has not been extensively discussed in the literature is the change in stage operating point that arises due to mass introduction midway through the machine. This effect complicates the analysis of the true performance impact on a turbine and must be accounted for in an assessment of the overall benefit of such a system. In this paper, we develop a low-order (“mean-line”) analysis in an attempt to bring clarity to this issue. We then present results from experiments conducted in the Oxford Turbine Research Facility, a 1.5-stage transonic rotating facility capable of matching non-dimensional engine conditions. In the experiments, effusion cooling was implemented over a sector of the rotor casing spanning 24 degrees or four rotor-blade pitches. Rotor-exit radial traverse and HP vane loading measurements were conducted locally to the cooled sector. Results are compared to baseline tests conducted without cooling. To assess the degree to which experimental results with only a sector of the annulus cooled would provide an accurate indication of stage operating point changes (when measured local to the annulus) in an annular (engine-like) environment, unsteady Reynolds-averaged Navier–Stokes (URANS) simulations were performed. In particular, simulations of a full annulus with an effusion-cooled sector were compared to a periodic simulation with fully annular effusion cooling. The results—perhaps surprisingly—suggest that a cooled sector is sufficient to infer the changes in an annular system, provided measurements are performed locally to the sector. Experiments conducted with fixed 1.5-stage boundary conditions showed increases in both mid-stage static pressure and stage-exit total pressure with cooling. The mean-line model and URANS predictions were in good agreement with the experimental data and also showed an increase in stage reaction and a reduction in turbine-inlet (mainstream) mass flowrate with cooling. Finally, the URANS predictions were used to show that with cooling, there are changes both locally to the cooled casing (changes to the tip-leakage and secondary flow structures) and globally (changes to the bulk-flow velocity triangles). An absolute stage efficiency benefit of 0.7% was predicted for a coolant-to-mainstream mass flowrate ratio of 2.2%. By running with a number of different boundary conditions, steady RANS simulations were used to estimate the relative contributions to the efficiency improvement due to the changes in operating point and aerodynamics in the blade-tip region. For the present configuration, both changes contribute positively to the improvement in stage efficiency.

Effect of grid displacement models on sensitivity derivatives computed by the continuous adjoint method in aerodynamic and conjugate heat transfer shape optimization

ABSTRACT For aerodynamic and conjugate heat transfer problems, the work reported in this article investigated the effect of the grid displacement model on the derivatives of an objective function with respect to the design variables. A comparison was made in the first step of the study between reference sensitivity derivatives computed by finite differences and different grid displacement models (volumetric B-splines, Laplace partial differential equations, Delaunay graphs and inverse distance weighting). Then, a continuous adjoint method including the adjoint to the Laplace grid displacement model was used to recompute sensitivity derivatives. To shed more light and to support the authors' findings, an alternative continuous adjoint method for computing the objective function gradient in terms of the field integrals of grid sensitivities was also formulated and programmed. Finally, the effect of an inconsistent differentiation of the grid displacement model on the optimized solution was investigated. The choice of the grid displacement model did not affect the sensitivity derivatives in any of the cases examined.

Impact of atmospheric stability conditions on heat fluxes from Alexandria Eastern Harbor, Egypt

The fluxes of energy through the water surface influence the water balance and regulate heat storage. This study analyzed the impact of stability condition of the atmosphere on the fluxes of heat on daily average time scale at Alexandria Eastern Harbor (AEH), Egypt. The method used here is depending on the bulk aerodynamic transfer method using standard meteorological parameters. The stability conditions of the atmosphere above the surface water can influence the convective and evaporative heat fluxes from the surface water. Unstable conditions of the atmosphere occurred 96.09% of the time during the study period (from 6/6/2010 to 16/2/2011) and resulted in 24.55% increments in the calculated average evaporation, when compared to the neutral condition. The results showed that an unsteady condition of the atmosphere has a significant influence in increasing evaporation in addition to sensible heat flux of AEH surface water.

Strategy for the determination of unsteady aerodynamic forces on elongated bodies in grid-generated turbulent flow

In this study, we developed a general method for estimating the unsteady aerodynamic forces on elongated bodies in grid-generated turbulent flow. The key to this method is the identification of the one-wavenumber aerodynamic transfer function (ATF) of bluff sections. Based on our previous studies, the accuracy of the strip theory in estimating the unsteady aerodynamic forces on bluff sections in isotropic homogeneous turbulence is higher than that of a thin airfoil. The thin airfoil section is therefore intended to serve as a standard configuration to calibrate the experimental parameters to satisfy the accuracy of the strip theory. This can provide a road map for the experimental determination of the unsteady aerodynamic forces on elongated bodies with different configurations in turbulent flow. To explore the deviations between the ATFs of airfoil and bluff sections, buffeting force measurement wind tunnel tests were performed on NACA 0015 airfoils and 5:1 rectangular (REC) cylinders with different length-width ratios at a 0° attack angle in grid-generated turbulence. The measured one-wavenumber ATFs of the airfoil sections correspond strongly to the theoretical predictions. In addition, it was found that the one-wavenumber ATF of the REC model is larger than Sears’ function at low reduced streamwise wavenumbers, which is explained by the difference between the lift generation mechanisms of the bluff and airfoil sections in grid-generated turbulence.

PERFORMANCE ENHANCEMENT OF AIRCRAFT ENGINE AXIAL FLOW TURBINE USING THEORETICAL, EXPERIMENTAL AND NUMERICAL APPROACHES – A REVIEW

Axial flow turbine is widely used in gas turbines for expansion of hot gases, emerging from the combustion chamber. The turbine expands the flow and generates power to drive the compressor and fan. The designing needs to accommodate high speeds and altitudes, as well as reduce losses in order to improve stage efficiency and overall efficiency. Some of the problems are tip leakage flow, high thermal loads on the blades, airfoil erosion, etc. Using public domain literature, a comprehensive review was carried out to get detailed understanding of the working and new techniques used to overcome losses of axial flow turbine. The present paper is a summary of literature of axial flow turbine over the span of three decades. The review covers Theoretical, Experimental and Numerical approaches, used in the literature for research on secondary flows, tip leakage losses, heat transfer coefficients, etc. This paper uses three broad classifications, namely aerodynamic performance, heat transfer and blade tip. This paper aims to aid researchers to understand the advancements in the field of aircraft engine axial flow turbines.

An integrated algorithm for hypersonic fluid–thermal–structural analysis of aerodynamically heated cylindrical leading edge

The accurate and efficient prediction of the fluid–thermal–structural performance of thermal protection systems on hypersonic vehicles to protect against severe aerodynamic heating is attracting increasing worldwide attention. In this paper, a new integrated fluid-structural-thermal investigation based on the finite volume method is proposed to study the thermal behavior of aerodynamically heated cylinder leading edges in hypersonic flows. A unified integral equation system is developed based on the governing equations for the physical processes of aerodynamic heating and structural heat transfer, which is resolved by using an up-wind finite volume method and a new two-thermal-resistance model in one integrated, vectorized computer program. To demonstrate its capability and reliability, applications for steady/unsteady fluid–thermal–structural analysis are demonstrated on aerodynamically heated cylinder leading edges at Ma 6.47. The results show that the steady maximum temperature of the cylinder can reach approximately 648 K at the stagnation point, and the unsteady results are in good agreement with the experimental data and related references. Compared with the partitioned approach, the integrated method shows better computational stability with relatively small sensitivity to mesh scale and time step, reducing the computation time for the same unsteady case by approximately 50%. The present study indicates that the integrated approach has potential for significant improvements and efficiency in predicting long-endurance fluid-structural-thermal problems of hypersonic vehicles.

Lake‐Atmosphere Heat Flux Dynamics of a Thermokarst Lake in Arctic Siberia

AbstractWe conducted eddy covariance measurements from April to August 2014 on a Siberian thermokarst lake. The study site is located in the Lena River Delta and characterized as a floating ice lake. Heat fluxes differed in magnitudes, directions and temporal patterns depending on the lake surface conditions (“frozen” ice cover, ice cover melt, and open water). Significant heat release during frozen ice cover conditions highlighted the importance of lakes for the landscape heat budget and water balance. The energy balance was nearly closed during the open water period and highlighted the impact of melting energy on its closure during the ice cover period. Sensible and latent heat dynamics were driven by temperature and water vapor gradients scaled by wind speed, respectively. We calculated bulk aerodynamics transfer coefficients and evaluated the performance of the derived in situ and three independent heat flux parameterization schemes. We found that bulk transfer models perform moderately to poorly for the different lake surface conditions. During the open water period small‐scale temporal variability could not be represented by the models, particularly in case of latent heat flux. The model results were less sensitive to the specific model type than to the accuracy of the surface water temperature measurement, which is dependent on a well‐thought‐out measurement design. Our study stresses considerations that are crucial for similar campaigns in the future, in order to face the measurement challenges encountered on arctic lakes especially during the ice cover period.

Physical controls on half‐hourly, daily, and monthly turbulent flux and energy budget over a high‐altitude small lake on the Tibetan Plateau

AbstractPrecise measurements of evaporation and understanding of the physical controls on turbulent heat flux over lakes have fundamental significance for catchment‐scale water balance analysis and local‐scale climate modeling. The observation and simulation of lake‐air turbulent flux processes have been widely carried out, but studies that examine high‐altitude lakes on the Tibetan Plateau are still rare, especially for small lakes. An eddy covariance (EC) system, together with a four‐component radiation sensor and instruments for measuring water temperature profiles, was set up in a small lake within the Nam Co basin in April 2012 for long‐term evaporation and energy budget observations. With the valuable measurements collected during the ice‐free periods in 2012 and 2013, the main conclusions are summarized as follows: First, a bulk aerodynamic transfer model (B model), with parameters optimized for the specific wave pattern in the small lake, could provide reliable and consistent results with EC measurements, and B model simulations are suitable for data interpolation due to inadequate footprint or malfunction of the EC instrument. Second, the total evaporation in this small lake (812 mm) is approximately 200 mm larger than that from adjacent Nam Co (approximately 627 mm) during their ice‐free seasons. Third, wind speed shows significance at temporal scales of half hourly, whereas water vapor and temperature gradients have higher correlations over temporal scales of daily and monthly in lake‐air turbulent heat exchange. Finally, energy stored during April to June is mainly released during September to November, suggesting an energy balance closure value of 0.97.

Laboratory modelling of the transfer processes between the ocean and atmosphere in the boundary layers

The processes of momentum and heat transfer between ocean and atmosphere in the boundary layer were investigated within laboratory modeling for a wide range of wind speed and surface wave including hurricane conditions. Experiments were carried out on the Wind-Wave Flume of the Large Thermostratified Tank of IAP RAS. A special net located under the surface at different depths allows to vary parameters of surface waves independently on wind parameters. Theory of self-similarity of air flow parameters in the flume was used to calculate values aerodynamic and heat transfer coefficients from the measured velocity and temperature profiles by Pito and hotfilm gauges respectively. Simultaneous measurements of surface elevation with system wire allow to obtain spectra and integral parameters of waves. It was demonstrated that in contrast to the drag coefficient, heat transfer coefficient is virtually independent of wind speed and wave parameters to the moment of the beginning of spray generation and then increases rapidly.

Secondary flow and heat transfer coefficient distributions in the developing flow region of ribbed turbine blade cooling passages

This paper reports an experimental and numerical study of the development and coupling of aerodynamic flows and heat transfer within a model ribbed internal cooling passage to provide insight into the development of secondary flows. Static instrumentation was installed at the end of a long smooth passage and used to measure local flow features in a series of experiments where ribs were incrementally added upstream. This improves test turnaround time and allows higher-resolution heat transfer coefficient distributions to be captured, using a hybrid transient liquid crystal technique. A composite heat transfer coefficient distribution for a 12-rib-pitch passage is reported: notably the behaviour is dominated by the development of the secondary flow in the passage throughout. Both the aerodynamic and heat transfer test data were compared to numerical simulations developed using a commercial computational fluid dynamics solver. By conducting a number of simulations it was possible to interrogate the validity of the underlying assumptions of the experimental strategy; their validity is discussed. The results capture the developing size and strength of the vortical structures in secondary flow. The local flow field was shown to be strongly coupled to the enhancement of heat transfer coefficient. Comparison of the experimental and numerical data generally shows excellent agreement in the level of heat transfer coefficient predicted, though the numerical simulations fail to capture some local enhancement on both the ribbed and smooth surfaces. Where this was the case, the coupled flow and heat transfer measurements were able to identify missing velocity field characteristics.

Identification of Unsteady Aerodynamic Forces from Forced Motion Wind Tunnel Experiments

The Active Aeroelastic Test Bench is used for the study of low subsonic unsteady aerodynamics through forced motion experiments of rigid wings in pitch and plunge. The use of highly dynamic electric linear actuators allows for arbitrary motion in both the pitch and plunge degrees of freedom. In this paper, we discuss the forces measured on a constant section NACA 0018 wing subjected to isolated single and multisine motion in pitch or plunge. A data-driven approach is used, in which the importance of filtering and averaging of the noisy wind tunnel data is discussed. It is concluded from the forced motion experiments that a good agreement between the single and multisine experiments exists. However, only the pitch experiments agree with predictions from Theodorsen’s unsteady aerodynamics theory. The plunge experiments show the presence of major nonlinear contributions in the measured force response. Because of friction in the linear bearings of the setup, it cannot be excluded that these are generated by the plunging mechanism or the setup itself. Additionally, it is illustrated how the use of multisine signals for the identification of unsteady aerodynamic transfer function models allows for a reduction of wind tunnel test time by a factor of 10.

Some influence factors in aerodynamic heat transfer numerical simulation of jet-interaction flow

Some influence factors in aerodynamic heat transfer numerical simulation of jet-interaction flow

Effect of dynamic and thermal prehistory on aerodynamic characteristics and heat transfer behind a sudden expansion in a round tube

The results of a numerical study of the influence of the thicknesses of dynamic and thermal boundary layers on turbulent separation and heat transfer in a tube with sudden expansion are presented. The first part of this work studies the influence of the thickness of the dynamic boundary layer, which was varied by changing the length of the stabilization area within the maximal extent possible: from zero to half of the tube diameter. In the second part of the study, the flow before separation was hydrodynamically stabilized and the thermal layer before the expansion could simultaneously change its thickness from 0 to D1/2. The Reynolds number was varied in the range of \(\text{Re}_{{{\text{D}}_{1} }} = 6.7 \cdot 10^{3} \,{\text{to}}\,1.33 \cdot 10^{5}\), and the degree of tube expansion remained constant at ER = (D2/D1)2 = 1.78. A significant effect of the thickness of the separated boundary layer on both dynamic and thermal characteristics of the flow is shown. In particular, it was found out that with an increase in the thickness of the boundary layer the recirculation zone increases and the maximal Nusselt number decreases. It was determined that the growth of the heat layer thickness does not affect the hydrodynamic characteristics of the flow after separation but does lead to a reduction of heat transfer intensity in the separation area and removal of the coordinates of maximal heat transfer from the point of tube expansion. The generalizing dependence for the maximal Nusselt number at various thermal layer thicknesses is given. Comparison with experimental data confirmed the main trends in the behavior of heat and mass transfer processes in separated flows behind a step with different thermal prehistories.

Observation and simulation of lake‐air heat and water transfer processes in a high‐altitude shallow lake on the Tibetan Plateau

AbstractLakes are an important part of the landscape on the Tibetan Plateau. Most of the Plateau lakes' area has been expanding in recent years, but lake‐atmosphere energy and water interaction is poorly understood because of a lack of observational data and adequate modeling systems. Based on the eddy covariance observation over a high‐altitude shallow and small lake (the small Nam Co Lake) during an ice‐free period from 10 April to 30 August 2012, this study analyzes the lake‐air heat and water vapor turbulent transfer processes and evaluates two popular lake‐air exchange models: a bulk aerodynamic transfer model (B model) and a multilayer model (M model). Our main results are as follows: (1) observations show that the bulk transfer coefficient (CE) and roughness length (zoq) for water are higher than those for heat (CH and z0h), especially under low wind speed; (2) both models underestimate turbulent fluxes due to inaccurate values of the Charnock coefficient (α) and the roughness Reynolds number (Rr) which are both important parameters for calculating the roughness length for momentum (z0m) over water; (3) α within a reasonable range of 0.013–0.035 for rough flow and Rr for smooth flow (Rr = 0.11) are 0.031 and 0.54, respectively, by our observation. The wave pattern of shorter wavelength gives a larger z0m in the small and shallow lake; and (4) the B model and the M model gave consistent results, and both models are more suitable for simulation of turbulent flux exchange after z0m optimization.

Computational studies of buildings' thermal state

This article deals with applying numerical methods of thermal condition modeling of buildings and their component parts in heat-and-power engineering. Some research results in this area are also presented. The main purpose of the study is to improve energy efficiency of buildings’ thermal power on the basis of thermal conditions analysis. The object of the study is the thermodynamic parameters of the thermal state of the buildings heated by radiators of radiative-convective type. This article presents methods of modeling of aerodynamic and heat transfer processes in the buildings with the help of software package ANSYS CFX. The research results can be applied by energy auditors in the field of heat-and-power engineering to assess compliance of the comfortable conditions inside the building, to analyze its thermal state, to assess the effectiveness of various energy-saving measures.