Features of a Cooling System Simulation Tool Used in Industrial Preliminary Design Stage

2004 ◽  
Author(s):  
Stefano Zecchi ◽  
Lorenzo Arcangeli ◽  
Bruno Facchini ◽  
Daniele Coutandin
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling System ◽  
Design Stage ◽  
Preliminary Design ◽  
Simulation Tool ◽  
Cooling Systems ◽  
Preliminary Design Stage

Due to expected increases in gas turbine performance, strictly related to firing temperature, heat transfer is a major issue in design processes. To keep components temperature levels below design requirements, cooling systems are commonly used. Nowadays, nozzle and blade cooling systems have reached a high degree of complexity. In a preliminary design stage, both experimental and 3D numerical analyses are usually not very suitable to define geometry, coolant mass flow rate or cooling system typology. This is mainly due to the uncertainty on several parameters, i.e. pressure distributions and materials properties, and their undefined interaction. This work presents a simulation tool useful to provide system cooling development with qualitative and quantitative information about metal temperature, coolant mass flow rate, heat transfer and much more. This tool couples energy, momentum and mass flow conservation equations together with experimental correlations for heat transfer and pressure losses. Metal conduction is solved by two dimensional calculations for several blade to blade sections. This methodology allows to investigate several cooling system configurations and compare them in a relatively short time. Main features of this simulation tool are shown comparing obtained results with experimental data.

scholarly journals A Numerical Analysis of the Air-Cooling System of a Spark Ignition Aeronautical Engine

2020 ◽  
Vol 197 ◽  
pp. 06003
Author(s):  
Maria Faruoli ◽  
Annarita Viggiano ◽  
Paolo Caso ◽  
Vinicio Magi
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling System ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Air Cooling ◽  
Air Mass ◽  
Air Cooling System

It is well known that spark ignition internal combustion engines for aeronautical applications operate within a specific temperature range to avoid structural damages, detonations and loss of efficiency of the combustion process. An accurate assessment of the cooling system performance is a crucial aspect in order to guarantee broad operating conditions of the engine. In this framework, the use of a Conjugate Heat Transfer method is a proper choice, since it allows to estimate both the heat fluxes between the engine walls and the cooling air and the temperature distribution along the outer wall surfaces of the engine, and to perform parametric analyses by varying the engine operating conditions. In this work, the air-cooling system of a 4-cylinder spark ignition engine, designed by CMD Engine Company for aeronautical applications, is analysed in order to evaluate the amount of the air mass flow rate to guarantee the heat transfer under full load operating conditions. A preliminary validation of the model is performed by comparing the results with available experimental data. A parametric study is also performed to assess the influence of the controlling parameters on the cooling system efficiency. This study is carried out by varying the inlet air mass flow rate from 1.0 kg/s to 1.5 kg/s and the temperature of the inner wall surfaces of the engine combustion chambers from 390 K to 430 K.

Heat Transfer Characteristics of a Rotor-Stator System With Small Radial Outflow

2012 ◽  
Author(s):  
Li Lin ◽  
Jing Ren ◽  
Hongde Jiang ◽  
Peter Childs
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cooling System ◽  
Small Mass ◽  
Eckert Number ◽  
Air Cooling ◽  
Air Cooling System ◽  
Radial Outflow

In some cases, the mass flow rate needed to prevent ingress through rim seals in turbine is smaller than that entrained by a free disk. In order to obtain the heat transfer features of the rotor-stator system at such a small mass flow rate, a combined computational and theoretical study has been carried out. It is found that the average Nusselt number (Nuav) on the rotor drops approximately linearly down to zero with decreasing turbulent flow parameter (λt) when λt is smaller than λt,c (λt,c < λt,fd), while Nuav almost keeps constant when λt is larger than λt,c. A correlation between Nuav and λt has been developed, which is expected to be useful in determining disk temperatures in the preliminary design of an internal air cooling system. The Eckert number, which can express the relationship between heat generated by windage and heat conducted through disk, turns out to be an important nondimensional number in describing the heat transfer features of such rotor-stator systems. Moreover, the effect of rotational speed on heat transfer when λt,c<λt<λt,fd has been studied, further identifying the significance of the Eckert number.

scholarly journals Experimental Investigation of Thermal and Pressure Performance in Computer Cooling Systems Using Different Types of Nanofluids

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1231 ◽  
Author(s):  
Alfaryjat ◽  
Miron ◽  
Pop ◽  
Apostol ◽  
Stefanescu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Base Fluid ◽  
Pumping Power ◽  
Cooling Systems

A modern computer generates a great amount of heat while working. In order to secure appropriate working conditions by extracting the heat, a specific mechanism should be used. This research paper presents the effect of nanofluids on the microchannel heat sink performance of computer cooling systems experimentally. CeO2, Al2O3 and ZrO2 nanoparticles suspended in 20% ethylene glycol and 80% distilled water are used as working fluids in the experiment. The concentration of the nanoparticles ranges from 0.5% to 2%, mass flow rate ranges from 0.028 kg/s to 0.084 kg/s, and the ambient temperature ranges from 25 °C to 40 °C. Regarding the thermal component, parameters such as thermophysical properties of the nanofluids and base fluids, central processing unit (CPU) temperature, heat transfer coefficient, pressure drop, and pumping power have been experimentally investigated. The results show that CeO2-EG/DW, at a concentration of 2% and a mass flow rate of 0.084 kg/s, has with 8% a lower temperature than the other nanofluids and with 29% a higher heat transfer coefficient compared with the base fluid. The Al2O3-EG/DW shows the lowest pressure drop and pumping power, while the CeO2-EG/DW and ZrO2-EG/DW show the highest. However, a slight increase of pumping power and pressure drop can be accepted, considering the high improvement that the nanofluid brings in computer cooling performance compared to the base fluid.

Effect of pre-swirl nozzle closure modes on unsteady flow and heat transfer characteristics in a pre-swirl system of aero-engine

2021 ◽  
pp. 095441002110191
Author(s):  
Gaowen Liu ◽  
Zhao Lei ◽  
Aqiang Lin ◽  
Qing Feng ◽  
Yan Chen
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Thermodynamic Characteristics ◽  
Circumferential Direction ◽  
Temperature Changes ◽  
Air Supply ◽  
Cooling Air

The pre-swirl system is of great importance for temperature drop and cooling air supply. This study aims to investigate the influencing mechanism of heat transfer, nonuniform thermodynamic characteristics, and cooling air supply sensitivity in a pre-swirl system by the application of the flow control method of the pre-swirl nozzle. A novel test rig was proposed to actively control the supplied cooling air mass flow rate by three adjustable pre-swirl nozzles. Then, the transient problem of the pre-swirl system was numerically conducted by comparison with 60°, 120°, and 180° rotating disk cavity cases, which were verified with the experiment results. Results show that the partial nozzle closure will aggravate the fluctuation of air supply mass flow rate and temperature. When three parts of nozzles are closed evenly at 120° in the circumferential direction, the maximum value of the nonuniformity coefficient of air supply mass flow rate changes to 3.1% and that of temperature changes to 0.25%. When six parts of nozzles are closed evenly at 60° in the circumferential direction, the maximum nonuniformity coefficient of air supply mass flow rate changes to 1.4% and that of temperature changes to 0.20%. However, different partial nozzle closure modes have little effect on the average air supply parameters. Closing 14.3% of the nozzle area will reduce the air supply mass flow rate by 9.9% and the average air supply temperature by about 1 K.

scholarly journals Cooling Performance Enhancement of Air-Cooled Condensers by Guiding Air Flow

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3503
Author(s):  
Huang ◽  
Chen ◽  
Yang ◽  
Du ◽  
Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Dissipation ◽  
Performance Enhancement ◽  
Cooling System ◽  
Wind Effects ◽  
Cooling Performance ◽  
Air Cooled Condensers ◽  
Arc Shape

Adverse wind effects on the thermo-flow performances of air-cooled condensers (ACCs) can be effectively restrained by wind-proof devices, such as air deflectors. Based on a 2 × 300 MW coal-fired power generation unit, two types (plane and arc) of air deflectors were installed beneath the peripheral fans to improve the ACC’s cooling performance. With and without air deflectors, the air velocity, temperature, and pressure fields near the ACCs were simulated and analyzed in various windy conditions. The total air mass flow rate and unit back pressure were calculated and compared. The results show that, with the guidance of deflectors, reverse flows are obviously suppressed in the upwind condenser cells under windy conditions, which is conducive to an increased mass flow rate and heat dissipation and, subsequently, introduces a favorable thermo-flow performance of the cooling system. When the wind speed increases, the leading flow effect of the air deflectors improves, and improvements in the ACC’s performance in the wind directions of 45° and –45° are more satisfactory. However, hot plume recirculation may impede performance when the wind direction is 0°. For all cases, air deflectors in an arc shape are recommended to restrain the disadvantageous wind effects.

Heat Transfer and Flow Friction Characteristics for Compact Cold Plates

2003 ◽  
Vol 125 (1) ◽  
pp. 104-113 ◽  
Author(s):  
Chang-Yuan Liu ◽  
Ying-Huei Hung
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Thermal Resistance ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Average Nusselt Number ◽  
Cold Plate ◽  
Air Mass

Both experimental and theoretical investigations on the heat transfer and flow friction characteristics of compact cold plates have been performed. From the results, the local and average temperature rises on the cold plate surface increase with increasing chip heat flux or decreasing air mass flow rate. Besides, the effect of chip heat flux on the thermal resistance of cold plate is insignificant; while the thermal resistance of cold plate decreases with increasing air mass flow rate. Three empirical correlations of thermal resistance in terms of air mass flow rate with a power of −0.228 are presented. As for average Nusselt number, the effect of chip heat flux on the average Nusselt number is insignificant; while the average Nusselt number of the cold plate increases with increasing Reynolds number. An empirical relationship between Nu¯cp and Re can be correlated. In the flow frictional aspect, the overall pressure drop of the cold plate increases with increasing air mass flow rate; while it is insignificantly affected by chip heat flux. An empirical correlation of the overall pressure drop in terms of air mass flow rate with a power of 1.265 is presented. Finally, both heat transfer performance factor “j” and pumping power factor “f” decrease with increasing Reynolds number in a power of 0.805; while they are independent of chip heat flux. The Colburn analogy can be adequately employed in the study.

scholarly journals Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (2S2) ◽  
pp. 143-147 ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Hot Water ◽  
Working Fluid ◽  
Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

scholarly journals ANALYSIS OF EVAPORATOR EFFECTIVENESS ON 1/2 CYCLE REFRIGERATION SYSTEMS: A CASE STUDY ON LPG FUELED VEHICLES

2020 ◽  
Vol 82 (3) ◽  
Author(s):  
Muji Setiyo ◽  
Budi Waluyo ◽  
Nurkholis Hamidi
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Exchange Process ◽  
Cooling Curve ◽  
Heat Exchange Process ◽  
Heat Transfer Capacity ◽  
The Ideal

The ½ cycle refrigeration system on LPG fueled vehicles has a significant cooling effect. However, the cooling is very dependent on the heat exchange process in the evaporator. Therefore, this paper analyses the deviation of the actual cooling curve from the ideal scenario carried out on a laboratory scale. The analytical method used is the calculation of the effectiveness of the evaporator, which compares the actual to the potential heat transfer capacity. The LPG flow rate was varied from 1-6 g/s, while the evaporation pressure ranged between 0.05, 0.10, and 0.15 MPa, which applied to compact type evaporators with dimensions of 262 ´ 200 mm, with a thickness of 65 mm. The research results confirm that the higher the LPG mass flow rate, the lower the heat transfer effectiveness. At the higher LPG mass flow rate, heat transfer occurs less optimally,  due to incomplete evaporation of LPG in the evaporator.

Conjugate Heat Transfer Analysis on Generic Rim Seal Configurations in Rotor-Stator System

2018 ◽  
Author(s):  
Xingyun Jia ◽  
Liguo Wang ◽  
Qun Zheng ◽  
Hai Zhang ◽  
Yuting Jiang
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Minimum Mass ◽  
Aerodynamic Efficiency ◽  
Axial Clearance ◽  
The Impact

Performance of generic rim seal configurations, axial-clearance rim seal (ACS), radial-clearance rim seal (RCS), radial-axial clearance rim seal (RACS) are compared under realistic working conditions. Conjugate heat transfer analysis on rim seal is performed in this paper to understand the impact of ingestion on disc temperature. Results show that seal effectiveness and cooling effectiveness of RACS are the best when compared with ACS and RCS, the minimum mass flow rate for seal of RACS is 75% of that of RCS, and 34.6% of ACS. Authors compare the disc temperature distribution between different generic rim seal configurations where the RACS seems to be favorable in terms of low disc temperature. In addition, RACS has higher air-cooled aerodynamic efficiency, minimizing the mainstream performance penalty when compared with ACS and RCS. Corresponding to the respective minimum mass flow rate for seal, the air-cooled aerodynamic efficiency of RACS is 23.71% higher than that of ACS, and 12.79% higher than the RCS.

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