Values Of Pressure Loss Research Articles

The One-Dimensional Flow Pressure Loss Correction Model Based on the Particle Flow through Concrete Bend

The rheological behavior of concrete pumping in the bend section is complex. The existing conversion calculation for pumping pressure loss based on the straight pipe section often fails to meet engineering precision requirements. This paper develops a pressure loss correction model for a concrete pumping bend section based on a new one-dimensional flow model for the straight pipe section simulation of particle flow; the study analyzes the impact of parameters such as elbow shape and pumping flow rate on pressure loss. An equivalent conversion relationship between the bend section and the straight section is established. The comparison with the measured pressure values from the project shows that the relative error between the pressure loss values calculated by the correction model and the actual measurements is 15.8%.

Numerical Study of Fluid Flow in a Gyroid-Shaped Heat Transfer Element

This paper deals with the design of porous geometry of a heat transfer element. The proposed geometry combines a gyroid triply periodic minimal surface with the recursive principle of geometric body creation. The designed geometry is based on an attempt to increase the heat transfer surface while eliminating negative impacts on the fluid characteristics in the form of pressure loss or increase of the friction coefficient. The proposed geometry of the heat transfer element was compared with a pair of geometries based on the basic gyroid shape but with different channel size parameters. A numerical simulation was performed in Ansys Fluent 2020 R1 using the SST k-omega turbulence model for flow velocities in the range of 0.01 m.s−1 to 0.5 m.s−1, which covered a wide range of the Reynolds number and thus also flow forms in terms of the turbulence intensity. The presented results clearly show lower values of pressure loss and friction coefficient of the proposed geometry compared to the evaluated porous structures. Also, at the same time, they describe the factors positively influencing the mixing process of the liquid in the proposed element, which leads to an increase in the efficiency of the heat transfer process.

One-Dimensional Modeling of the Pressure Loss in Concrete Pumping and Experimental Verification

An accurate formula for calculating the pressure loss in concrete pumping plays a significant guiding role in the design and service process of pump trucks. Based on the flow characteristics of concrete pumping, a straight pipe one-dimensional model for the pressure loss is developed, in which both the viscous force of the mortar in the lubrication layer and the blocking effect of coarse aggregate particles are considered. First, the complex geometrical shapes of the aggregate particles are geometrically reconstructed by using a HandySCAN noncontact scanner and the reverse modeling software Geomagic Design X (v.19.0.2). Then, the equivalent spherical size of nonspherical aggregate particles is calculated according to the equal hydraulic radius principle. The blocking effect of the aggregate particles is converted into the wall roughness. Finally, an explicit expression for the pressure loss in concrete pumping is deduced by using Modi’s equation, Bernoulli’s equation, and Darcy’s formula, and the calculated value is compared with the measured value at a corresponding experimental site. The results indicate that the pressure loss values calculated with the one-dimensional flow model are closer to the actual pumping pressure loss values. The relative error between the results and the actual pumping pressure loss value is about 20.2%.

Novel air duct designs to estimate the windshield demisting issue for a commercial vehicle

This study is about the fog on the windshields of passenger buses because it makes it hard for drivers to see, which is dangerous. The goal of the research is to come up with an effective way to spread the produced mist. According to the study, the air duct design, which is connected to the car’s defroster and defrosting system by Kraft hoses, has to be upgraded. The analysis identifies areas in which the current air duct design might be enhanced and then makes design modifications to create a superior design. By conducting climatic chamber experiments on a vehicle equipped with the first air duct design and tracking the actual air velocity values at the nozzle tips, the success of the new technique is assessed. The boundary conditions for the analysis are the observed values. The study involves the utilization of a commercially available software package to conduct investigations on both the original and modified air duct designs. The software package employs a k-ε turbulence model that is known to produce reliable results. The data demonstrate that the adjustments made in light of the comparison produced beneficial effects. The maximum air velocities were increased by 23%, while the pressure loss values of the left and right fans were reduced by 2.5% and 2.9%, respectively, due to the modification of the air duct. Significant energy was saved because of the decrease in fan pressure loss, which led to decreases in the power consumption of the left and right fans of 4.2% and 4.7%, respectively. This comparison shows that the newly built air ducts actually increased the flow rate at the system’s fan outlets by 40%.

Mechanical Performance Analysis of Hydrostatic Thrust Bearing under Microbevel Parameters

Background: Heavy-duty hydrostatic bearings of the original parallel friction pair are prone to hydrostatic loss problems during operation. Aims: To solve the failure problem, the original hydrostatic oil pad was designed as a micro-inclined plane, and the dynamic pressure caused by the micro-wedge of the oil pad at a higher speed was used to compensate for the static pressure loss of the bearing. objective: For a new type q1-205 microbevel double rectangular cavity hydrostatic bearing. Objective: This study aims to design a new type of q1-205 micro bevel double rectangular cavity hydrostatic bearing. Method: The mathematical model of oil film theoretical analysis of hydrostatic bearing with the micro-inclined surface was established, including the flow equation of a double rectangular cavity with a micro-inclined surface and static and dynamic bearing capacity equation. result: The oil film lubrication performance of the bearing with the wedge parameters of 0mm, 0.02mm, 0.04mm, 0.06mm, 0.08mm and 0.10mm was simulated by the finite volume method, the comprehensive influence law of the wedge-shaped parameters on the vorticity and flow rate of the oil cavity pressure fluid was revealed. Finally, the oil cavity pressure changes of oil films with different wedge parameters under certain load and speed were tested by design experiments, and the theoretical analysis and simulation were verified. Result: In this paper, the mechanical properties of oil film with tilt height between 0 and 0.1mm were simulated with variable viscosity, and the distribution law of pressure field under different working conditions was obtained. Through the experimental study, the pressure data of parallel flat pads and tilting pads under different working conditions are measured and compared with the simulation data. Conclusion: The pressure loss value of the oil pad designed in this paper is relatively small under extreme working conditions. The overall loss rate is about 10% ~ 20%, and the dynamic pressure compensation rate is about 16%. The dynamic pressure generated by the slight inclination Angle can well compensate for the static pressure loss.

INVESTIGATION OF THE FUEL-AIR FLOW INSIDE A VORTEX FURNACE WITH A FLUIDIZED BED USING A SPECIAL AIR-DISTRIBUTING NOZZLE

The article presents the results of an experimental study of the fuel-air flow inside a vortex furnace with a fluidized bed using a special air distribution nozzle. Nowadays, the issue of dependence on fossil energy resources is the most important problem for the countries of Europe. One of the promising solutions to this problem is the use of vortex solid fuel furnaces for burning low-calorie types of fuel, such as waste from the woodworking and agricultural industries. Our country has developed agricultural and woodworking sectors of the economy, so the amount of waste from these industries is significant, which allows them to be used to cover the energy needs of the state. At the same time, there is a significant number of solid fuel boilers on the territory of Ukraine that can be used for this task. The main difficulties in burning low-grade fuels in solid-fuel boilers are the low level of efficiency of these vortex furnaces and insufficient theoretical information about this. To conduct the experiment, a special installation in the form of a cylinder with a nozzle inside is used. The nozzle has a plate inclination of 15 °, which does not exceed 10% of the total live cross-sectional area of the chamber of the experimental setup. In the course of the experiment, the boundary conditions for the formation of a vortex flow at different amounts of fuel and different air flows were determined, and the values of pressure loss and flow velocity were shown. The results are presented in graphical and tabular form. For example, for 2.9 kg of sawdust, the maximum speed of vortex flow formation is 0.72 m/s, for 5.8 kg this value is 0.57 m/s. The obtained results make it possible to formulate recommendations for the improvement of existing solid fuel furnaces due to the use of special nozzles for the intensification of combustion processes. This creates prospects for the development of the country's energy sector. Keywords: fuel combustion, vortex furnaces, furnace aerodynamics, special nozzle.

Investigation of the fuel-air flow inside a vortex furnace with a fluidized bed using a special air-distributing nozzle.

The search for resources alternative to fossil sources of thermal energy is a constant component of the development of the energy sector of any country. This issue is now most urgent due to various political processes and the constant decrease of the total amount of non-renewable natural resources. One of the ways to implement the issue of replacing natural gas, coal and other types of fossil fuels is the burning of waste from agriculture and the woodworking industry. But this is associated with a significant number of technical difficulties and an insufficient theoretical basis for implementation. The article presents the results of an experimental study of the fuel-air flow inside a fluidized-bed vortex furnace using a special air-distributing nozzle. A nozzle with a 15ͦ slope of the plates is used, which does not exceed 10% of the total area of ​​the free section of the chamber of the experimental setup. In the course of the experiment, the limiting conditions for the formation of a vortex flow at different amounts of fuel and different air flow rates are indicated, and the values ​​of pressure losses and flow rates are shown. So for 2.9 kg of sawdust, the maximum speed of formation of a vortex flow is 0.72 m/s, for 5.8 kg this value is 0.57 m/s. The results obtained make it possible to formulate recommendations for the improvement of existing solid fuel furnaces through the use of special nozzles to intensify combustion processes. In the future, it is planned to consider other types of solid fuel and the influence of different angles of inclination of the blades on the air distribution nozzle on the aerodynamic characteristics inside the vortex furnace. All this will make it possible to formulate recommendations for the improvement of existing solid fuel vortex furnaces.

Experimental Research on the Effects of Suction Ports on Twin Screw Expander Performance

An organic Rankine cycle (ORC) system is an efficient technology for generating power from low-grade thermal sources. Twin screw expanders are widely used in ORC systems. Pressure loss caused by a suction port influences the suction process and the system performance. In this paper, the effects of suction ports on twin screw expander performance are experimentally investigated. The pressure loss value of R245fa is measured under different working conditions, and its effects on the suction coefficient are discussed. Results show that a lower rotation speed results in a lower pressure loss value and a higher suction coefficient under certain working conditions. Increasing the suction pressure leads to a higher pressure loss value but a lower pressure loss ratio. Discharge pressure has little effect on the suction process.

Random Forest Slurry Pressure Loss Model Based on Loop Experiment

A reasonable arrangement of filling pipelines can solve the problems of low line magnification, a high flow rate, large pipe pressure, etc., in deep well filling slurry transportation. The transportation pressure loss value of filling slurry is the main parameter for the layout design of filling pipelines. At present, pressure loss data are mainly obtained through the loop pipe experiment, which has problems such as a large amount of labor, high cost, low efficiency, and a limited amount of experimental data. In this paper, combined with a new generation of artificial intelligence technology, the random forest machine learning algorithm is used to analyze and model the experimental data of a loop pipe to predict the pressure loss of slurry transportation. The degree of precision reaches 0.9747, which meets the design accuracy requirements, and it can replace the loop pipe experiment to assist with the filling design.

Rigorous modeling of frictional pressure loss in inclined annuli using artificial intelligence methods

One of the challenging issues during underbalanced drilling (UBD) is the prediction of frictional loss in the presence of three-phases of drilling fluid, cuttings, and air. In the current work, three innovative machine learning-based algorithms based-on Gradient tree boosting (GTB), Adaptive neuro-fuzzy inference system (ANFIS), and Extreme learning machine (ELM) have been suggested to calculate the frictional loss in gas-based drilling fluids containing cuttings in inclined annuli. A number of 216 real frictional pressure loss data in terms of hole inclination, pipe rotation, rate of penetration, and flow rates of each phase have been collected to train and validate the frictional pressure loss models. The visual and statistical comparisons of the frictional pressure loss models and actual values reveal that models have a fascinating ability in prediction of the frictional pressure loss for inclined wells. Besides, the GTB model has the best performance with R2 = 1, RMSE = 0.0031, MRE = 0.415, STD = 0.0023, and MSE≈0 in comparison with actual frictional pressure loss values. Furthermore, an exciting sensitivity analysis has been used to identify the effectiveness of each operational parameter on frictional pressure loss for inclined annuli. Due to these facts, the current work can be applied as an assistant in the development of drilling simulators in complicated field conditions.

Rheological properties of wood polymer composites at high shear rates – Evaluation of additional pressure losses as a result of inlet effects

The study presents the results of rheological tests of wood polymer composites (WPC) on a polypropylene matrix. The influence of the filler on the additional pressure losses as a result of entrance effects has been analysed. The tests were carried out with the use of a capillary rheometer and a rheological head at the values of apparent share rate up to 101 860 s−1.The influence of the Bagley corrections on the apparent viscosity curve defined for the tested composites was determined. In the case of rheological tests at low shear rates, omit the additional pressure losses does not significantly affect the determined rheological properties. It was observed that with the increase of the filler content and shearing rate, the value of pressure losses significantly increases. It is necessary to consider the values of pressure losses in rheological measurements of rheological properties of WPC with the use of capillary rheometers.

МОДЕЛИРОВАНИЕ ПАРАМЕТРОВ ПОТОКА В НАПОРНЫХ ТРУБОПРОВОДАХ С ДИСКРЕТНЫМ ОТБОРОМ ЖИДКОСТИ

Every year more and more urgent is the task of introducing a new generation of irrigation systems in the agro-industrial complex, with higher technical and economic indicators and resource-saving technologies. At the same time, the improvement of systems is directly related to the optimization of water pipelines, carefully selected parameters of which will significantly reduce material consumption and cost, increase work efficiency, optimize modes, and reduce the intensity of water supply. The goal is to simulate flow parameters in pressure pipelines with discrete fluid withdrawal. Studies show some increase in head along a perforated pipeline when liquid is withdrawn. The physical meaning of this process is explained by the transition of kinetic energy into potential energy during the selection of liquid along the length of the pipeline. Theoretical studies of the movement of a fluid with a flow rate varying along the length of the pipeline made it possible to obtain dependences that describe the characteristics of the flow in the presence of both uniform and non-uniform installation of drainage systems along the pipeline and pressure losses, taking into account the discreteness parameter, which takes into account the number of branches per unit length. To refine the flow separation factor, studies were carried out, the results of which showed the independence of the ratio of the velocities of the main flow and the velocity of the jet outflow from the diameter of the holes. The obtained results show that the flow disconnection factor is in the range from 0.66 to 0.87. The conducted experimental studies allow us to conclude that the flow discreteness parameter decreases with an increase in the number of drainage systems. The value of pressure loss in case of discrete extraction can be expressed in terms of the magnitude of pressure loss in case of uniform flow selection and discreteness parameter. Comparison of the calculated and experimental values shows good agreement between the results.

A numerical study on heating performance of horizontal and vertical earth-air heat exchangers with equal pipe lengths

In this study, heating performances of horizontal and vertical earth-air heat exchangers with equal pipe lengths were evaluated in ANSYS FLUENT 19.2 simulation program based on CFD for the winter period of Bitlis, Turkey. Thermal per?formance analyses regarding vertical and horizontal 3-D-modeled earth-air heat exchangers were evaluated in steady-state condition of the simulation program for different values of Re = 5?103, 104, 2?104, 4?104, 6?104, 8?104, and 105 numbers by using standard k-? turbulence model. Numerical results obtained from CFD based simulation program were compared with a numerical study in the literature, and it was determined that there was a consistency between the results. The pressure loss and fan power values of horizontal and vertical earth-air heat exchangers were also investigated in addition their thermal performances. A good agreement was found between the pressure loss values obtained from the theoretical and simulation calculations of both earth-air heat exchangers. Considering the temperature increases in both earth-air heat exchangers, the highest and lowest temperature increases were observed in vertical earth-air heat exchanger with 22.52 K and 10.67 K, respectively. The best thermal performance was observed in vertical earth-air heat exchanger for 5?103, 104, and 2?104 values of Reynolds number and in horizontal earth-air heat exchanger for 4?104, 6?104, 8?104, and 105 values of Reynolds number.

Experimental Study of a Rotary Heat Exchanger with a Metal Mesh Matrix

This paper describes the experimental study of a metal mesh matrix of a rotary heat exchanger model including calculation of its regeneration ratio. Temperature oscillograms showing the temperature in tne matrix channel are shown Also the pressure loss value is found for channels of the matrix. The pressure loss value for the case of having a matrix formed by flat metal plates was also calculated in order to compare the calculated values with the ones obtained experimentally for the mesh matrix.

Research of hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks (wild cotton)

The object of this research is the hydrodynamics of the stationary layer of crushed cotton stalks. One of the most problematic areas is the influence of the physical and mechanical characteristics of the stationary layer of crushed cotton stalks on the hydrodynamics of filtration drying. In the course of research, methods of physical and mathematical modeling are used. Sieve analysis is used to determine the granulometric composition of the polydisperse mixture of crushed cotton stalks. The granulometric composition of the crushed stalks of cotton is determined and the graphical dependence of the percentage of each fraction is presented. The hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks are experimentally investigated, and a graphical dependence of pressure losses on the fictitious rate of gas flow filtration is presented. It is found that pressure losses in the stationary layer of crushed cotton stalks are parabolic, which indicates the influence of both inertial and viscous components on pressure losses. The unknown coefficients of the modified Ergun equation are determined on the basis of experimental data. The correlation dependence between the experimental and theoretically calculated values is presented and it is shown that the maximum relative error is 9.6 %, which is quite acceptable for practical calculations. The results of experimental studies are also presented in the form of a graphical dependence of the Euler number on the Reynolds number. Based on the generalization of the experimental data, the calculated dependences are obtained in the form of dimensionless complexes, which describe the hydrodynamics of the gas flow filtration through a stationary layer of crushed cotton stalks. This makes it possible to predict the energy costs for creating a differential pressure, with an accuracy sufficient for practical calculations. The ratio of the experimental values of pressure losses to the theoretically calculated ones, depending on the Reynolds number, is graphically presented. It is shown that the maximum relative error does not exceed 8 %. The proposed generalizations of experimental data will make it possible to determine the energy consumption for creating a pressure drop at the design stage of the drying equipment, as well as to calculate the optimal process parameters and predict its economic feasibility.

The Data-Driven Modeling of Pressure Loss in Multi-Batch Refined Oil Pipelines with Drag Reducer Using Long Short-Term Memory (LSTM) Network

Due to the addition of the drag reducer in refined oil pipelines for increasing the pipeline throughput as well as reducing energy consumption, the classical method based on the Darcy-Weisbach Formula for precise pressure loss calculation presents a large error. Additionally, the way to accurately calculate the pressure loss of the refined oil pipeline with the drag reducer is in urgent need. The accurate pressure loss value can be used as the input parameter of pump scheduling or batch scheduling models of refined oil pipelines, which can ensure the safe operation of the pipeline system, achieving the goal of energy-saving and cost reduction. This paper proposes the data-driven modeling of pressure loss for multi-batch refined oil pipelines with the drag reducer in high accuracy. The multi-batch sequential transportation process and the differences in the physical properties between different kinds of refined oil in the pipelines are taken into account. By analyzing the changes of the drag reduction rate over time and the autocorrelation of the pressure loss sequence data, the sequential time effect of the drag reducer on calculating pressure loss is considered and therefore, the long short-term memory (LSTM) network is utilized. The neural network structure with two LSTM layers is designed. Moreover, the input features of the proposed model are naturally inherited from the Darcy-Weisbach Formula and on adaptation to the multi-batch sequential transportation process in refined oil pipelines, using the particle swarm optimization (PSO) algorithm for network hyperparameter tuning. Case studies show that the proposed data-driven model based on the LSTM network is valid and capable of considering the multi-batch sequential transportation process. Furthermore, the proposed model outperforms the models based on the Darcy-Weisbach Formula and multilayer perceptron (MLP) from previous studies in accuracy. The MAPEs of the proposed model of pipelines with the drag reducer are all less than 4.7% and the best performance on the testing data is 1.3627%, which can provide the calculation results of pressure loss in high accuracy. The results also indicate that the model’s capturing sequential effect of the drag reducer from the input data set contributed to improving the calculation accuracy and generalization ability.

Investigation of gas gathering pipelines operation efficiency and selection of improvement methods

Purpose: The article implies theoretical and experimental studies of the liquid pollution accumulations impact on the efficiency of gathering gas pipelines operation at the Yuliivskyi oil and gas condensate production facility (OGCPF). Research of efficiency of gas pipelines cleaning by various methods. Design/methodology/approach: The research methodology consists of determining the hydraulic efficiency of gathering gas pipelines before and after cleaning of their internal cavity by different methods and comparing the obtained results, which allows to objectively evaluate the efficiency of any cleaning method. CFD simulation of gas-dynamic processes in low sections of gas pipelines with liquid contaminants. Findings: Experimental studies of cleaning efficiency in the inner cavity of the gas gathering pipelines of the Yuliivskyi OGCPF by various methods, including: supply of surfactant solution, creating a high-speed gas flow, use of foam pistons were performed. It was established that cleaning the inner cavity of gas gathering pipelines by supplying a surfactant solution leads to an increase in the coefficient of hydraulic efficiency by 2%-4.5%, creating a high-speed gas flow by 4%-7%, and under certain conditions by 8%-10 % and more. However, for two gas pipelines the use of foam pistons allowed to increase the coefficient of hydraulic efficiency from 5.7 % to 10.5 % with a multiplicity of foam from 50 to 90. be recommended for other deposits.The results of CFD simulation showed that the accumulation of liquid contaminants in the lowered sections of gas pipelines affects gas-dynamic processes and leads to pressure losses above the values provided by the technological regime. With the increase in liquid contaminants volume the pressure losses occur. Moreover, with a small amount of contamination (up to 0.006 m3), liquid contaminants do not have a significant effect on pressure loss. If the contaminants volume in the lowered section of the pipeline is greater than the specified value, the pressure loss increases by parabolic dependence. The increase in mass flow leads to an increase in the value of pressure loss at the site of liquid contamination. Moreover, the greater the mass flow, the greater the impact of its changes on the pressure loss. The CFD simulation performed made it possible not only to determine the patterns of pressure loss in places of liquid contaminants accumulation in the inner cavity of gas pipelines, but also to understand the gas-dynamic processes in such places, which is an unconditional advantage of this method over experimental. Research limitations/implications: The obtained simulation results showed that the increase in the volume of liquid contaminants in the inner cavity of gas gathering pipelines leads to an increase in pressure losses above the value provided by the technological regime. To achieve maximum cleaning of gas gathering pipelines, it is necessary to develop a new method that will combine the considered. Practical implications: The performed experimental results make it possible to take a more thorough approach to cleaning the inner cavity of gas gathering pipelines and to forecast in advance to what extent the hydraulic efficiency of gas gathering pipelines can be increased. Originality/value: The obtained results of CFD simulation of gas-dynamic processes in lowered sections of gas pipelines with liquid contaminants, experimental studies of the effectiveness of various methods of cleaning the inner cavity of gas gathering pipelines has original value.

The effect of different inflating volume on the measurement accuracy of the modified cuff pressure measurement method.

To evaluate the effect of different inflation volume on the measurement accuracy of the modified cuff pressure measurement method in different shapes of cuffs, so as to provide reference for the correct monitoring of cuff pressure in clinic. In vitro study: The traditional cuff pressure measurement method (the cuff pressure gauge before measurement shows 0 cm H2O) and the modified cuff pressure measurement method (the cuff pressure before measurement shows 25 cm H2O, 28 cm H2O, 30 cm H2O or 32 cm H2O) were used to measure cylindrical and tapered cuffs, and the effect of different inflation volume on cuff pressure was analyzed statistically. Clinical study: patients with the artificial airway established by orotracheal intubation or tracheotomy in Neuro-ICU were prospectively selected as subjects, and the measurement procedure was the same as in vitro study. In vitro study showed that the pressure loss values of cylindrical cuff and tapered cuff using the traditional cuff pressure measurement method were (3.75 ± 0.31) cm H2O and (4.92 ± 0.44) cm H2O, respectively, and clinical study showed that the pressure loss values were (5.07 ± 0.83) cm H2O and (5.17 ± 0.93) cm H2O, respectively. The actual measured values measured by the traditional cuff pressure measurement method of the two cuff shapes were compared with the corrected target value of 28 cm H2O, and the differences were statistically significant (P < 0.000). Both in vitro and clinical study had shown that all differences between the actual measured value and the corrected target value using the modified cuff pressure measurement method (measured with 25 cm H2O, 30 cm H2O, 32 cm H2O) were statistically significant (P < 0.000), and the range of overall differences was (0–1.23 ± 0.25) cm H2O. In vitro study had shown that the pressure variation coefficient (CV) of the tapered cuff was greater than that of the cylindrical cuff, and the difference was statistically significant (3.08 ± 0.25 VS 2.41 ± 0.21, P < 0.000). The traditional cuff pressure measurement method can directly lead to the cuff pressure drop, which is easy to cause the leakage of secretions on the cuffs and the misjudgment of the cuff pressure by medical personnel. However, the modified cuff pressure measurement method can effectively reduce cuff pressure loss, and taking the actual cuff pressure value as the inflation volume is the highest measurement accuracy.The tapered cuff is more susceptible to air volume, so it is necessary to pay attention to its measurement and correction in clinical practice.

OPTIMIZATION OF DIFFERENTIAL PRESSURE DISTRIBUTION BETWEEN GAS SUPPLY SYSTEM SECTIONS

The paper proposes the optimum distribution of the differential pressure between gas supply system sections and gas consumption, depending on the settlement planning and development. This provides a 10–15 % reduction in metal and material consumption of gas supply systems and a 4–5 % cost reduction. The hydraulic analysis of differential pressure distribution does not allow to purposefully distribute the calculated pressure drop. The pipeline diameter is usually selected according to the estimated gas flow rate and specific pressure loss per unit length of gas supply system sections. Then, in accordance with the State standard, the condition of compliance and non-exceedance of the obtained differential pressure is checked with the standard value. If this condition is not met, the pipeline diameter is adjusted for design reasons.This work conducts additional research into the differential pressure distribution between gas supply system sections. Materials and methods include the assessment methodology for the effectiveness of differential pressure distribution between gas supply system sections.Although many publications are devoted to the optimization of gas pressure distribution systems, the proposed solutions and the recommendations developed in this paper are fragmentary, often contradictory, since they do not consider the completeness and diversity of strategic factors.The paper shows that the pressure loss values obtained for domestic gas-based units with a reduced nominal pressure, are much less than those given in regulatory documents. According to the analysis, the settlement development, population density in gas-supplied territories, and technical conditions of gas-supplied buildings, have a decisive influence on the unit costs of gas supply systems.

PERANCANGAN SISTEM TATA UDARA PADA RUANG NICU DI LANTAI 3 RUMAH SAKIT “X”

Salah satu upaya untuk mengurangi Hospital-acquired Infections (HAIs, atau yang biasa disebut dengan infeksi nosokomial) pada ruang NICU, adalah dengan merancang sistem tata udara khusus, yang ASHRAE HVAC Design Manual for Hospital and Clinics. Parameter-parameter yang perlu dikondisikan dalam sistem tata udara yaitu suhu, kelembaban udara relatif, tekanan ruangan, kebersihan udara, ventilasi, distribusi udara pada ruangan. Metode perhitungan kapasitas pendinginan yang digunakan dalam penelitian ini adalah dengan menggunakan Cooling Load Temperature Difference (CLTD). Sedangkan metode yang digunakan dalam merancang saluran distribusi udara adalah metode Equal Friction Loss. Dari hasil perhitungan, didapat kapasitas pendinginan yang dihasilkan oleh ruang NICU adalah sebesar 8,803 kW. Sedangkan kapasitas pemanasannya adalah sebesar 3,660 kW. Nilai total pressure loss untuk saluran udara yang dirancang adalah sebesar 44,85 Pa. Filter yang built-in dengan unit AC adalah pre-filter dan medium filter. Sehingga, HEPA filter diletakkan pada ceiling.