Convective Components Research Articles

Horizontal Heat Flux Spread in an Inner Corner of Buildings

This study investigates fire separation distances as essential means of passive fire protection in building design. The focus is on the inner corner configuration of building exterior walls, which represents the worst-case scenario for façade fire spread outside of a building. The inner-corner configuration appears to increase the intensity of the radiative heat flux due to reflection and reradiation of heat. Comprehensive approaches for determining fire separation distances around the various façade geometries can be found, but none of them is focused on detailed descriptions of the unprotected area in an inner corner. A medium-scale scenario was chosen and was experimentally validated with a radiant panel for a better understanding of heat flux spread. This paper compares the experiment with analytical and numerical models. The analytical model is based on the Stefan–Boltzmann law and the calculated configuration factor as per Eurocode 1. The numerical model combines radiative and convective components of the heat flux because convection is non-negligible near the heat source. Experimental data confirm the prediction based on the numerical and analytical model and show agreement. The final increase in heat flux due to the corner configuration investigated at the medium scale reaches up to 29%.

Microphysical characteristics of torrential predecessor rain events over the Yangtze River Delta Area and the related tropical cyclones

The precipitation structures and microphysical characteristics of predecessor rain events (PREs) over the Yangtze River Delta area and related tropical cyclones (TCs) from 2014 to 2019 were investigated using Dual-frequency Precipitation radar data from Global Precipitation Measurement (GPM) for drop size distributions (DSDs). Results showed that the total mean rain rate of PREs was larger than that of TCs, primarily due to higher convective and stratiform rain rates, with enhanced fractional coverage of convective rain in PREs. Examination of microphysical characteristics revealed that a greater quantity of small-sized droplets and a smaller quantity of medium- as well as large-sized droplets contributed towards PREs in comparison with TCs. The conclusion still holds when partitioning DSDs based on different precipitation rate categories. Further investigation of DSDs using gamma functions illustrated that precipitation in PREs had lower average mass-weighted diameters (Dm) and enhanced normalized number concentration (Nw) compared with TCs; partitioning precipitation into convective and stratiform components illustrated a larger Dm and lower Nw in TCs than PREs. The analysis of microphysical and thermodynamical processes using the reanalysis data indicates that relatively intense convective activity with drier conditions may be favorable to enhancing raindrop growth through collision-coalescence processes, as a result of larger Dm in TCs than PREs. The empirical relations (Z–R algorithms) applied in different rain regimes (stratiform, convective, and total PREs) revealed significant diversities, relying on weather conditions and geographical locations. Plain language summaryThe Yangtze River Delta area is an important economic belt in China. Under climate change, observed frequent occurrences of weather extremes of heavy rainfall and tropical cyclones (TCs) exert adverse effects on economic development in this region. Thus, a deep understanding of the mechanism of TCs torrential rainfall in the Yangtze River Delta area is urgently necessary. In this study, we investigated the precipitation patterns and microphysical characteristics of predecessor rain events (PREs) in the Yangtze River Delta region, and their association with TCs in the South China Sea-Western North Pacific Ocean (SCS-WNPO) area from 2014 to 2019. We found that PREs had a higher total mean precipitation rate than TCs. Further examination using gamma functions demonstrated that PREs exhibited lower average mass-weighted diameters (Dm) and higher normalized intercept parameters (Nw) than TCs. This pattern persisted when distinguishing between convective and stratiform precipitation components. We believe that our study makes a significant contribution to the literature because these results provide valuable insights into the distinct precipitation characteristics of PREs and TCs in the study region and contribute to a better understanding of tropical cyclone-related rainfall patterns, and act as a scientific basis for disaster mitigation.

Ідентифікація координат імпульсних джерел забруднень стічних вод в кусково-однорідних середовищах числовими методами квазіконформних відображень

The process of filtration in a single-connected curvilinear domain bounded by streamlines and equipotential lines is considered, provided that the medium under study is piecewise homogeneous. It is assumed that certain unknown curves act as impulse sources of pollution. It is assumed that their propagation occurs only due to the convective component, without significantly affecting the filtration background. It is proposed to use the method of characteristics for solving the convection equation to identify the coordinates of pollution sources. In this case, quasipotentials at the fluid inlet and outlet at the boundary of the domain, coordinates of the points of pollution detection, and the time of its movement downstream can serve as a priori data. The general algorithm involves the adaptation of the numerical quasiconformal mapping method to build a hydrodynamic mesh, according to which the coordinates of pollution sources are identified. Numerical experiments were carried out and analysed. In particular, it is emphasised that with a sufficient mesh division, the maximum discrepancies between the a priori known data and the calculated data are small compared to the size of the studied domain. This indicates the effectiveness of the developed algorithm for identifying pollution sources in the case of a piecewise homogeneous environment. As an additional measure to reduce the magnitude of the uncertainties, it is proposed to use more accurate approximation schemes for specific expressions. On the other hand, there is an increase in computational complexity compared to the case of a continuous setting of the filtration coefficient. Given the relatively high accuracy of the calculations, it seems advisable to further develop an described approach to larger-scale in comparison with point sources of pollution and to spatial case. Taking into account the sensitivity of the solutions to the discontinuity of the filtration coefficient values, it is also worthwhile to introduce additional conditions at the contact of homogeneous media in the future.

Terrestrial Heat Flow and Lithospheric Thermal Structure Characteristics in Nanping City of Hainan

The Nanping geothermal field in Hainan is situated within the Wuzhi Mountain fold belt of the South China fold system based on its geotectonic units. Although there is abundant surface heat detected and widespread distribution of Late Mesozoic granite in the area, the geological background of geothermal resources remains unclear. In this article, we collected core samples from boreholes within the Nanping geothermal field to conduct testing and analysis on rock thermal conductivity and heat-production rate. By combining these results with temperature logging data, we discuss a method for diterming the heat flow background of convective geothermal system. Furthermore, the study analyzed the geothermal flux and deep thermal structure of the research area. The results demonstrate that the average radioactive heat production rate of the Baocheng rock mass in the study area is 3.16 μW/m³, primarily attributed to the decay heat of Th and U, while the heat contribution of K is negligible. The thermal conductivity values of the rocks are relatively high, ranging from 2.29 to 3.75 W/(mK), slightly exceeding the average thermal conductivity of the upper crust. The study area represents a typical convective geothermal field influenced by groundwater convection, exhibiting a high geothermal temperature gradient. Using the groundwater-correction method, the geothermal flux in the study area is calculated to be 89–108.27 mW/m², of which the thermal conduction component is 73.17 mW/m² and the convective component is 15.83–35.1 mW/m². Among these components, heat generated from radioactive decay of crustal radioactive elements contributes 35.44 mW/m² to thermal conduction, while deep mantle conduction accounts for a heat flux is 37.73 mW/m², with a ratio of 1:1.07 between them. The difference between crustal and mantle heat fluxes is minimal in this region, indicating an approximation towards a “crust-mantle heat source balance zone”. Furthermore, the thickness of the “hot” lithosphere in the study area ranges from 42 to 46 km, indicating significant characteristics of extension-thinning.

Computerized Principal Component–Canonical Discriminant Analysis Classification Model for Pollen Grain Identification Using Surface-Enhanced Raman Spectroscopy

Pollen identification and quantification are employed in various applications, and studies have been conducted to achieve precise automated pollen recognition to minimize the manual labor and subjectivity associated with human identification. The objective of the study was to evaluate the potential of surface-enhanced Raman spectroscopy (SERS) properties of pollen grain spectra, specifically within the spectral range of 582–1563 cm–1, using the convective assembly combined principal component–canonical discriminant analysis (PC-CDA) classification model. This research aimed to explore the feasibility of using this approach for the automated identification of pollen in the future. This approach facilitates the optimal arrangement of pollen grains and colloidal silver nanoprobes, thereby enhancing SERS spectra reproducibility using the convective assembly sampling method. Pollen grains can be characterized at a microscopic level without the need for purification-based analysis procedures. The findings demonstrate the possibility of rapid and accurate classification of pollen grains with the PC-CDA detection model with a 99.3% sensitivity, 97.6% specificity, and 98.5% accuracy. Research study indicates that the SERS properties of pollen spectra could serve as a promising method for automated pollen identification using the PC–CDA classification model.

Effect of Flexible Tank Wall on Seismic Response of Horizontal Storage Tank

Horizontal storage tanks are integral to the petrochemical industry but pose significant risks during earthquakes, potentially causing severe secondary disasters. Current seismic designs predominantly assume rigid tank walls, which can lead to an underestimation of seismic responses. This study introduces a novel analysis method for assessing the dynamic response of flexible-walled horizontal storage tanks. By separating the liquid velocity potential into convective and impulsive components and integrating these with beam vibration theory, we developed a simplified mechanical model. A parameter analysis and dynamic response research were conducted using numerical methods. Results indicate that flexible tank walls amplify seismic responses, including liquid dynamic pressure peaks, base shear, and overturning bending moments, compared to rigid walls. Additionally, the impact of flexible walls is more pronounced in tanks with larger radii, aspect ratios, diameter–thickness ratios, and H/R ratios. These findings highlight the necessity for revised seismic design approaches that consider wall flexibility to enhance the safety and resilience of horizontal storage tanks.

Non-linear sloshing characteristics of liquid inside a chamfered bottom tank with submerged internal object under near-and far-fault earthquakes

Cylindrical and rectangular-shaped tanks have a concentration of stagnant impulsive liquid at the bottom corners that do not participate in sloshing. While used as tuned liquid dampers (TLDs), this non-participating fluid adds extra liquid mass to the tank but does not have any role in the vibration control aspect. In the present study, to decrease the stagnant impulsive liquid, a chamfered bottom-shaped tank with a submerged internal object is demonstrated. Due to the high-energy velocity pulse present in near-fault earthquakes, there is a possibility of violent liquid sloshing which may cause unwanted structural damage to the tank. Hence, the present study focuses on the influence of near- and far-fault earthquakes on the non-linear seismic behavior of the tank with submerged internal object. The non-linear sloshing is modeled using the finite element method based on a combined Eulerian-Lagrangian approach. The accuracy of the present non-linear numerical model is checked by verifying the results with the previously published results. In addition to the absolute response, the dynamic convective and impulsive response components are quantified. The proposed non-linear finite element scheme can be utilized in the context of structure-mounted chamfer bottom TLDs in the future.

Mathematical description of protein extraction from muscle tissue of hydrobionts and determination of the effective molecular diffusion coefficient

The purpose of this work is to obtain an array of experimental data, kinetic dependences of the protein extracting from the particles of dispersed muscle tissue of hydrobionts (Alaska pollack), its mathematical description, and to find the molecular diffusion coefficients of proteins in the system of equations using solving the inverse problem of the modeling. This work’s novelty is to study swelling and protein extraction from animal tissue and its mathematical description. This study has established that the diffusion of proteins from the muscle tissue of hydrobionts during stirring suspension (raw material-extractant) occurs at a significantly higher rate than diffusion from raw materials of plant origin. It indicates the contribution of a convective component to the swelling process and dissolution of particles due to intensive blending and easy differentiability of muscular tissue particles of hydrobionts. Based on the solution of the mathematical model, the molecular diffusion coefficient of proteins from raw materials of animal origin (muscle tissue of hydrobionts) (3÷8)×10−9 m2/s, which exceeds the diffusion coefficients of carbohydrates from raw materials of plant origin (e.g., sugar 0.3×10−9 m2/s) by more than an order of magnitude. Researchers can use the obtained molecular diffusion coefficient to calculate the parameters of the diffusion process of proteins during its extraction from dispersed particles of hydrobionts.

Flow boiling of R32 and R410A inside brazed plate heat exchangers with different geometries

A proposed midterm substitute of R410A, mixture with 1924 GWP100 (Global Warming Potential over 100 years), is R32 (GWP100 = 677), which, although mildly flammable, is pure, relatively cheap, already available on the market, with different suppliers due to the absence of patents. Moreover, its thermo-physical properties are already well known. Increasingly stringent energy saving regulations are boosting the residential heat pump market, which typically requires reversible brazed plate heat exchangers to be used both as evaporators and condensers. This work reports an experimental analysis of the two refrigerants during flow boiling in brazed plate heat exchangers, varying the channel volumes. The number of plates of the heat exchangers ranges from 4 (1 refrigerant channel) to 120 (59 refrigerant channels in parallel). The heat transfer coefficient and the pressure drop have been measured for R410A and R32 at saturation temperature between 1.5 °C and 5.5 °C, outlet vapour superheating of 5 K, heat flux from 4 to 31 kW m−2, mass velocity from 8 to 87 kg m−2 s−1 and inlet channels vapour quality from 0.2 to 0.3. The number of plates affects the distribution of the liquid-vapour mixture in the channels and its effect is discussed by comparing the heat transfer coefficients. It is shown that the differences in performance between the two fluids increase with the mass velocity, suggesting the influence of a convective component on the heat transfer coefficient. This is further confirmed by comparing the data with the results of two different models from literature.

Interpreting Heat Flux Measurements in a Vitiated Backward-Facing Step Flow

The investigation of the relative impact of convective and radiative heat flux from vitiated gases to a combustor wall was performed in a backward-facing step combustor. Backward-facing step flows have many flow features of gas turbine combustors (recirculation, impingement, and boundary-layer development), but in a two-dimensional, nonproprietary geometry. Reynolds number, gas temperature, and plate temperature were varied as heat flux was measured in different regions of the flow. Measurements were made using a heat flux sensor and radiometer, which measure total and radiative heat flux, respectively. The highest total heat flux was measured at the impingement location and the lowest in the recirculation zone. Separating the total heat flux into the radiative and convective components is not straightforward and requires simulations of the experiment. Spectrally resolved Monte Carlo ray-tracing simulations are used to scale the radiative heat flux measurements for the separation of convective and radiative heat flux from the total heat flux measurements. These calculations show that only about 30% of incident radiation is captured by the radiometer due to spectral differences between the two sensors. Once the radiation measurement is corrected, experimental results show higher radiative than convective heat transfer at low Reynolds numbers (Reh=2000), highlighting the impact of radiative heat transfer in hot gas environments.

Anthropogenic heat from buildings in Los Angeles County: A simulation framework and assessment

Anthropogenic heat (AH), i.e., waste heat from buildings to the ambient environment, increases urban air temperature and contributes to the urban heat island effect, which leads to more air-conditioning energy use and higher associated waste heat during summer, forming a positive feedback loop. This study used a bottom-up simulation approach to develop a dataset of the annual hourly AH profiles for 1.7 million buildings in Los Angeles (LA) County for the year 2018 aggregated at three spatial resolutions: 450 m, 12 km, and the census tract. Building AH exhibits strong seasonal and diurnal patterns, as well as large spatial variations across the urban areas. Building AH peaks in May and reaches a maximum of 878 W/m2 within one of several AH hotspots in the region. Among the three major AH components (surface convection, heat rejection from HVAC systems, and zonal air exchange), the surface convection component is the largest, accounting for 78% of the total building AH across LA County. Higher AH is attributed to large building density, a high percentage of industrial buildings, and older building stock. While AH peaks during the day, the resulting ambient temperature increases are much larger during the night. During the July 2018 heatwave in LA County, building AH (excluding the surface component) leads to a daily maximum ambient temperature increase of up to 0.6 °C and a daily minimum ambient temperature increase of up to 2.9 °C. It is recommended that reducing summer building AH should be considered by policy makers in developing mitigation measures for cities to transition to clean energy while improving heat resilience.

Effects of varying heat transfer rates for borehole heat exchangers in layered subsurface with groundwater flow

The existence of groundwater flow adds a convective heat component to shallow geothermal heat pump systems, significantly improving heat transfer efficiency. Numerous analytical and numerical methods have been proposed to assess the impact of groundwater flow on ground heat exchangers. However, numerical simulations often require significant resources and time, while conventional analytical solutions overlook the time and depth-varying heat transfer rates, leading to inaccurate temperature predictions. This study proposes a computationally efficient semi-analytical solution by extending the line source solution and coupling it with a thermal resistance model. This approach addresses variations in heat transfer rate over time and depth, overcoming the limitations of conventional analytical solutions. Compared with a three-dimensional numerical model constructed in COMSOL Multiphysics, the average absolute percentage error (MAPE) of borehole wall temperatures for a U-shaped borehole heat exchanger (BHE) is approximately 1 %, across a wide range of water flow velocities and thermal conductivity ratios between two contacting geological layers. A significant advantage of the proposed solution is its computational efficiency. The proposed solution can complete long-term simulations with over 9,000 time steps in about 10 min, as opposed to numerical models that typically require several hours. The excellent computational efficiency and substantial accuracy make the proposed solution a simple and effective tool for the design and optimization of BHEs in engineering applications.

The microcirculation in the first days of ICU admission in critically ill COVID-19 patients is influenced by severity of disease

The objective of this study was to investigate the relationship between sublingual microcirculatory parameters and the severity of the disease in critically ill coronavirus disease 2019 (COVID-19) patients in the initial period of Intensive Care Unit (ICU) admission in a phase of the COVID-19 pandemic where patients were being treated with anti-inflammatory medication. In total, 35 critically ill COVID-19 patients were included. Twenty-one critically ill COVID-19 patients with a Sequential Organ Failure Assessment (SOFA) score below or equal to 7 were compared to 14 critically ill COVID-19 patients with a SOFA score exceeding 7. All patients received dexamethasone and tocilizumab at ICU admission. Microcirculatory measurements were performed within the first five days of ICU admission, preferably as soon as possible after admission. An increase in diffusive capacity of the microcirculation (total vessel density, functional capillary density, capillary hematocrit) and increased perfusion of the tissues by red blood cells was found in the critically ill COVID-19 patients with a SOFA score of 7–9 compared to the critically ill COVID-19 patients with a SOFA score ≤ 7. No such effects were found in the convective component of the microcirculation. These effects occurred in the presence of administration of anti-inflammatory medication.

Influence of thermal boundary layer on thermophysical properties of construction materials

The paper considers the influence of thermal boundary layer on the thermal conductivity coefficient of building materials. The influence of thermal boundary layer on the thermal characteristics is shown on the example of cellular materials such as foam concrete, gas silicate and vacuum-powder thermal insulation materials.New ideas about regularities and mechanism of action of such factors as pore size, thickness and composition of interstitial partitions on thermal conductivity of porous materials are proposed. The thermal characteristics of porous systems were analyzed using the theory of similarity (calculation of Grasgoff, Rayleigh, and Prandtl criteria). Calculation of these criteria showed that in cellular materials with pore diameter up to 4 mm the convective component does not influence the heat transfer coefficient. The thermal boundary layer, a low-moving thin layer of gas adsorbed on the inner surface of the pore, has a great influence on the heat transfer processes in the pore. The paper considers the structure of the thermal boundary layer from the approach of the electrical surface properties of the pore and the gas in it. It is shown that the structure of the thermal boundary layer depends on the surface charges of the solid phase and gas. In the environment of air or oxygen denser and more homogeneous in structure thermal boundary layer will have materials, which pore walls will have an effective positive charge, and the thermal boundary layer of materials with a large negative surface charge will be loose, inhomogeneous. In hydrogen medium, on the contrary, materials with an effective negative charge will have a denser and more homogeneous thermal boundary layer structure.

Heat flux measurement approach for an enhanced thermometric method: preliminary tests

In situ tests are suitable to confirm the real thermal performance of building components, and several significant on-site measurement techniques have been studied in literature. However, among them the Thermometric (THM) method has been poorly examined by the scientific community, thus having opportunities for improvement, being a quite a new and non-standardized technique. The theory behind this technique is the Newton’s law of cooling and the main issue is associated to the heat transfer coefficient for which there is no agreement about the value to use. Here, a simple experimental apparatus characterized by a vertical heated sample, suitably thermally insulated was realized. Sensors were installed and direct heat flux measurements through a heat flux plate were performed and compared with (i) the heat flows obtained through the THM method (test conducted using the internal heat transfer coefficient recommended by the ISO 6946) and (ii) the heat fluxes obtained through the proposal of an enhanced THM method based on dimensionless groups analysis, thus requiring data processing based on convective and radiative components.

Nonlinear dynamic assessment of sloshing in a seismically isolated rectangular liquid tank using laminated rubber bearing

The primary purpose of the research is to study the effect of free surface nonlinearity in the overall slosh dynamics of base-isolated liquid tank by developing a nonlinear finite element model under different frequency content of earthquakes. Six natural earthquakes are considered, which are categorized under low-, intermediate-, and high-frequency contents. The mixed Eulerian and Lagrangian technique is adopted based on the potential flow theory for developing the fluid domain. The efficacy of the developed computational model is verified with the existing results. The potential constraints of linear responses are demonstrated alongside the dominance of nonlinear counterparts. The slosh amplitudes are underestimated in the linear model, which emphasizes the importance of the present nonlinear approach in adequately determining the freeboard to prevent loss of liquid due to spillage and unexpected roof failure. The laminated rubber bearing isolator played a crucial role in reducing the total and impulsive components of hydrodynamic pressure as well as base shear for both linear and nonlinear approaches. However, the effect of nonlinearity is significant in the contribution of the convective component of pressure and base shear, irrespective of the frequency content of earthquakes. Also, the nonlinear convective base shear is greater than the linear counterpart for non-isolated and base-isolated tanks, and such phenomenon is marginal for higher frequency content motions. Furthermore, resonant studies of both the tank systems are performed using a harmonic ground acceleration. The seismic parameters of the base-isolated tank are amplified when the excitation frequency is very close to its fundamental sloshing frequency rather than the natural frequency of the isolator.

Experimentally validated numerical analyses on the seismic responses of extra-large LNG storage structures

Extra-large liquefied natural gas (LNG) storage tanks are comprised by a steel inner tank and an outer protective tank of prestressed reinforced concrete (PRC), both being very thin. These important lifeline infrastructures are prone to damage and even failure under earthquake during their service life. Convincing numerical simulation, verified by shake table tests, is a feasible tool to quantify the seismic responses and to mitigate the potential damage/failure of LNG storage structures. This work addresses systematically the three-dimensional finite element (FE) modeling, experimental validation and numerical simulations of such structures, with the soil–pile interaction of the foundation, the fluid–structure interaction of the inner tank and damage of the outer tank all properly accounted for. For the sake of computational efficiency with no loss of too much precision, the soil–pile interaction is described by the mass–damper–spring model, and the fluid–structure interaction by the mass–spring model with both the convective and impulsive components accounted for. Moreover, the nonlinear mechanical behavior of concrete is considered by the damaged-plasticity model regularized with the fracture energy. The concrete–steel interaction in PRC is practically dealt with by modifying the constitutive relations of concrete and steel rebars/tendons properly with the equilibrium and compatibility conditions accounted for. The FE modeling strategy is validated against the recently conducted benchmark shaking table test of a scaled extra-large LNG storage structure. The capability in capturing the overall dynamic responses, e.g., the hydrodynamic pressure and structural vibrations under seismic actions, etc., is sufficiently verified. Finally, the dynamic responses and structural reliability of an extra-large LNG storage tank under deterministic and stochastic seismic actions are numerically studied in details.

Slosh Dynamics of the Seismically Excited Chamfered Bottom Tank with Bottom-Mounted Internal Object

The inherent energy dissipation ability of the sloshing liquid is effective in vibration control of the supporting structure. Due to the advancement in the construction techniques in structural and mechanical fields, liquid containers of different geometrical configurations were required to avoid tank interference with rigid structural or mechanical components. The quantity of liquid that participates in the connective mode determines the effectiveness of the tuned liquid damper (TLD). To reduce the impulsive liquid mass and to increase the participation of liquid mass in the convective mode, a chamfered bottom tank with a bottom-mounted internal object is proposed in this study. A 2D finite element model developed employing the potential flow theory is used for the present numerical investigation. The effect of the frequency content of ground motion on the slosh dynamics of the chamfered bottom tank has been investigated under six different earthquake ground motions classified based on frequency contents. Also, the dynamic impulsive and convective components of base shear force and hydrodynamic pressure are quantified successfully. A parametric study has been performed to quantify the influence of the bottom-mounted object on the seismic response by altering the object’s height. The developed numerical model in this study can be utilized for tuning and designing structure-coupled chamfered bottom TLDs as well as the irregular liquid containers with internal submerged components.

Non-linear slosh dynamics of sloped wall tank with bottom-mounted object under seismic excitation

The present study deals with the investigation of the non-linear slosh dynamics of a sloped wall tank with bottom-mounted object under seismic excitation. The potential flow theory has been adopted for modeling the liquid domain with a mixed Eulerian-Lagrangian method. The nonlinear seismic response of a sloped wall tank with bottom-mounted rigid internal object is suitably investigated under six different earthquakes. The selected earthquakes are classified based on their PGA/PGV ratios. The base shear force and hydrodynamic pressure are successfully quantified along with the impulsive and convective components. In order to study the influence of the internal object on the hydrodynamic behavior of the liquid tank, a parametric investigation is performed by altering the object's height. The necessity of non-linear analysis is reasonably justified by comparison of the results with those obtained from linear analysis, where a significant difference is observed between the linear and non-linear hydrodynamic responses. The developed non-linear finite element model in the current study is found to be more effective than the linear model and may be employed in designing structure-coupled sloped wall TLDs.

ANALYSIS OF CALCULATION AND EXPERIMENTAL METHODS OF DETERMINING HEAT LOSSES THROUGH WINDOW CONSTRUCTION

Problem statement. Energy conservation in the conditions of deficit and constant growth in the cost of energy carriers is the main task of the housing and communal complex. Along with the use of energy-saving equipment in life support systems, a significant reduction in energy consumption can be achieved by introducing energy-efficient structural solutions into construction. Translucent structures are considered more unprotected, since heat losses through them can reach 54 % of the total, so they require new approaches to determining heat transfer coefficients. On the basis of the analysis of heat and mass transfer processes element by element for window blocks of non-standard shape, a correct estimate of the heat transfer coefficient was made. The purpose of the article on the basis of the analysis of the thermophysical processes formation through translucent enclosing structures, improve the dependences for calculating the heat transfer coefficient of double-glazed structures taking into acount the climatic load and establishing the relationship between their main thermotechnical characteristics. Results. Based on the analysis of thermophysical processes occurring in opaque structures, the dependence of the heat transfer coefficient of non-standard shape window block on the wind speed, taking into acount the orientation of the building height in the element-by-element determination, was obtained. The main factors affecting the value of the heat transfer coefficient of the window unit have been established, i. e., these dependencies can be used to evaluate energy-saving measures during an energy audit. Scientific novelty and practical value. Dependencies for determining the heat transfer coefficient of translucent structures, taking into acount heat loss through window frames, the location of the window in the wall opening, and structural solutions are obtained. An analysis of the results of heat transfer coefficients for windows of non-standard shape, which are aimed at choosing the optimal technical solutions of wine blocks from the standpoint of energy and resource saving, taking into acount climatic parameters, was conducted. Quantitative results of the radiant and convective components for the element-by-element determination of the heat transfer coefficient of window blocks and heat losses through them are obtained, allowing to establish the priority of energy-saving measures.