Karam H. Mohammed¹, Ashraf E. Al-Mirani¹, Bashar Mahmood Ali², Omar Rafae Alomar^1,*

Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 839-854, 2024, DOI:10.32604/fhmt.2024.052671

Abstract This work involves an experimental study on the performance of automobile air-conditioning systems by adding AlO nanoparticles to oil compressors to investigate their impacts on the enhancement of the speed cooling of refrigeration systems and to compare it with the system operated using only oil. The AlO nanoparticles have been added to the oil compressor for different ranges of mass concentration (Ø = 0.1%, Ø = 0.15% and Ø = 0.2%). The stability of AlO nanoparticles has been tested by direct observation for different time periods. The results indicated that the air conditioning system that More >

Vladimir Ya. Modorskii, Ivan E. Cherepanov^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 1031-1043, 2024, DOI:10.32604/fdmp.2024.048494

Abstract A transition to clean hydrogen energy will not be possible until the issues related to its production, transportation, storage, etc., are adequately resolved. Currently, however, it is possible to use methane-hydrogen mixtures. Natural gas can be transported using a pipeline system with the required pressure being maintained by gas compression stations. This method, however, is affected by some problems too. Compressors emergency stops can be induced by vibrations because in some cases, mechanical methods are not able to reduce the vibration amplitude. As an example, it is known that a gas-dynamic flow effect in labyrinth… More >

Nikola Stosic^**, Ian K. Smith, Ahmed Kovacevic

Frontiers in Heat and Mass Transfer, Vol.3, No.2, pp. 1-7, 2012, DOI:10.5098/hmt.v3.2.3003

Abstract Due to fast rotation of screw compressor rotors, temperature is uniform in the rotor cross section and temperature field is a function of the axial coordinate only. Apart of that the rotors in one cross section the rotors are simultaneously heated by hot gas on one side while cooled at another side by cold gas. As a result of identification of the main modes of heat transfer both in the rotors and between the rotors and their surroundings and the relative significance of each, a novel procedure is suggested to cool the rotors by injection… More >

M. Farid Yahya¹, Reduan Mat Dan^2,3,*, M. Fadzlee Samsubaha¹, Zaini Rashid¹, Azma Putra^2,3,*

Sound & Vibration, Vol.57, pp. 119-131, 2023, DOI:10.32604/sv.2023.045029

Abstract A case study of excessive vibration on a motor-compressor system is presented in this paper. After barely two months of operation, the reciprocating compressor motor’s routine monitoring revealed excessive axial vibration amplitude. For this reason, the Operational Modal Analysis (OMA) was carried out in order to identify the primary cause. According to the investigation, one of the harmonic components which was 18 times the motor’s running speed matched with a resonance frequency of 112 Hz. According to OMA study, the motor was vibrating in torsional motion because the compressor’s load had stimulated the entire motor-compressor More >

Aparna Kottapallia , Ramakrishna Konijeti^b,*

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-11, 2022, DOI:10.5098/hmt.19.11

Abstract Scroll technology is widely used in refrigerators as compressors. This research paper presents the performance of a scroll-type expander derived from a scroll compressor. The research is carried out at low pressures. The effect of mechanical load on performance has been evaluated using compressed air as a working fluid. Two stages of the evaluation process are carried out in this research. In the first stage, the scroll expander model is numerically simulated using the CFD approach to predict the factors influencing the scroll expander performance. In the later stage, an experiment is carried out on… More >

M. Maria Dominic Savio^1,*, T. Deepa¹, N. Bharathiraja², Anudeep Bonasu³

CMC-Computers, Materials & Continua, Vol.72, No.2, pp. 3815-3834, 2022, DOI:10.32604/cmc.2022.025924

Abstract The processor is greatly hampered by the large dataset of picture or multimedia data. The logic of approximation hardware is moving in the direction of multimedia processing with a given amount of acceptable mistake. This study proposes various higher-order approximate counter-based compressor (CBC) using input shuffled 6:3 CBC. In the Wallace multiplier using a CBC is a significant factor in partial product reduction. So the design of 10-4, 11-4, 12-4, 13-4 and 14-4 CBC are proposed in this paper using an input shuffled 6:3 compressor to attain two stage multiplications. The input shuffling aims to… More >

Pengfei Ju^1,2, Fangfei Ning^3,4,*, Zhiting Tong^1,2, Jingying Wang^5,6

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.3, pp. 761-773, 2022, DOI:10.32604/fdmp.2022.018841

Abstract In this paper, a numerical investigation into a spike-type rotating stall process is carried out considering a transonic compressor rotor (the NASA Rotor 37). Through solution of the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations, the evolution process from an initially circumferentially-symmetric near-stall flow field to a stable stall condition is simulated without adding any artificial disturbance. At the near-stall operating point, periodic fluctuations are present in the overall flow of the rotor. Moreover, the blockage region in the channel periodically shifts from middle span to the tip. This fluctuating condition does not directly lead to stall, More >

Nagarajan Shanmugam^*, Vijeyakumar Krishnasamy Natarajan, Kalaiselvi Sundaram, Saravanakumar Natarajan

Computer Systems Science and Engineering, Vol.42, No.2, pp. 619-638, 2022, DOI:10.32604/csse.2022.021008

Abstract In the recent years, error recovery circuits in optimized data path units are adopted with approximate computing methodology. In this paper the novel multipliers have effective utilization in the newly proposed two different 4:2 approximate compressors that generate Error free Sum (ES) and Error free Carry (EC). Proposed ES and Proposed EC in 4:2 compressors are used for performing Partial Product (PP) compression. The structural arrangement utilizes Dadda structure based PP. Due to the regularity of PP arrangement Dadda multiplier is chosen for compressor implementation that favors easy standard cell ASIC design. In this, the… More >

A. R. Mohanty^1,*, S. Fatima²

Sound & Vibration, Vol.54, No.4, pp. 247-256, 2020, DOI:10.32604/sv.2020.011011

Abstract This paper studies the acoustics of a frost free three door domestic refrigerator. Then, as a case study, the radiated noise reduction in the refrigerator using a natural material base composite is presented. Composites manufactured out of Jute, which is a plant fiber abundantly and cheaply available in India and Bangladesh are used in the noise reduction in the refrigerator. Mostly in this work, composites made out of felts of jute were used as barriers for noise control of the refrigerator. Measured acoustical, thermal and physical properties of various jute composites are reported. Noise sources More >

Daoming Shen^1,2,*, Chao Gui¹, Jinhong Xia¹, Songtao Xue^2,3

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 489-500, 2020, DOI:10.32604/fdmp.2020.08969

Abstract The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression ratio. Moreover, the following influential factors have been taken into account: evaporation temperature, condensation temperature and compressor suction-exhaust pressure ratio for different opening conditions of the compressor. The following quantities have been selected as the unit performance measurement indicators: refrigeration capacity, energy efficiency ratio (COP), compressor power consumption, and refrigerant flow rate. The experimental results indicate that the system refrigeration capacity and COP decrease with a More >