The Experts below are selected from a list of 555 Experts worldwide ranked by ideXlab platform
Shu Pengcheng - One of the best experts on this subject based on the ideXlab platform.
-
theoretical and experimental study on indicator diagram of twin screw refrigeration compressor
International Journal of Refrigeration-revue Internationale Du Froid, 2004Co-Authors: Wu Huage, Xing Ziwe, Shu PengchengAbstract:Abstract In this paper a new mathematical model for calculating the indicator diagram of twin screw refrigeration compressor is presented firstly. The geometric parameters related to the rotation angle of male rotor are used in the model such as groove volume, suction and discharge port area, slide valve bypass port area, leakage area etc. The effects of internal leakage through five paths, oil injection, gas–oil heat transfer, Refrigerant Property and partial loading etc. are taken into account simultaneously and separately in the theoretical study. To verify the model and the calculated p–V indicator diagram, experimental recording of p–V indicator diagram of twin screw refrigeration compressor is carried out. Various indicator diagrams are recorded successfully by a small pressure sensor embedded in the bottom of female rotor at the discharge side. The results of theoretical calculation are in good agreement with the measured data, which lead to conclusion that the model can be used as a powerful tool for performance prediction and product development.
Wu Huage - One of the best experts on this subject based on the ideXlab platform.
-
theoretical and experimental study on indicator diagram of twin screw refrigeration compressor
International Journal of Refrigeration-revue Internationale Du Froid, 2004Co-Authors: Wu Huage, Xing Ziwe, Shu PengchengAbstract:Abstract In this paper a new mathematical model for calculating the indicator diagram of twin screw refrigeration compressor is presented firstly. The geometric parameters related to the rotation angle of male rotor are used in the model such as groove volume, suction and discharge port area, slide valve bypass port area, leakage area etc. The effects of internal leakage through five paths, oil injection, gas–oil heat transfer, Refrigerant Property and partial loading etc. are taken into account simultaneously and separately in the theoretical study. To verify the model and the calculated p–V indicator diagram, experimental recording of p–V indicator diagram of twin screw refrigeration compressor is carried out. Various indicator diagrams are recorded successfully by a small pressure sensor embedded in the bottom of female rotor at the discharge side. The results of theoretical calculation are in good agreement with the measured data, which lead to conclusion that the model can be used as a powerful tool for performance prediction and product development.
Damilola C. Badejo - One of the best experts on this subject based on the ideXlab platform.
-
Experimental performance of LPG Refrigerant charges with varied concentration of TiO2 nano-lubricants in a domestic refrigerator
Case Studies in Thermal Engineering, 2017Co-Authors: Damola S. Adelekan, Moradeyo K. Odunfa, Richard O. Leramo, Sunday Olayinka Oyedepo, Taiwo O. Babarinde, Olayinka S. Ohunakin, Damilola C. BadejoAbstract:This article present an experimental investigation of varied mass charges of Liquefied Petroleum Gas (40g, 50g, 60g and 70g) enhanced with varied TiO2 nanoparticle/mineral oil concentrations (0.2g/L, 0.4g/L and 0.6g/L nano-lubricants) in a R134a compressor of a domestic refrigerator. Performance tests investigated at steady state included: pull down time, power consumption, compressor power input, cooling capacity and coefficient of performance (COP). Analysis was based on temperature and pressure readings obtained from appropriate gauges attached to the test rig. Refrigerant Property characteristics were obtained using Ref-Prop NIST 9.0 software. Results obtained showed almost equal evaporator air temperatures and reduction in power consumption for all tested nano-lubricant concentrations except at 70g charge of LPG using 0.6g/L nano-lubricant. Furthermore, the lowest compressor power input was found to be 21W and obtained using 70g of LPG with either of 0.2g/L or 0.4g/L nano-lubricants. At 70g of LPG using 0.6g/L concentration of nano-lubricant, highest cooling capacity index of 65W was obtained while the highest COP of 2.8 was obtained with 40g charge of LPG using 0.4g/L concentration of nanolubricant. In conclusion, LPG-TiO2 nano-lubricant mixture works safely and efficiently in domestic refrigerators without modification of capillary tube length, but requires adequate optimization.
Radermacher Reinhard - One of the best experts on this subject based on the ideXlab platform.
-
Uncertainty Analysis on Prediction of Heat Transfer Coefficient and Pressure Drop in Heat Exchangers Due to Refrigerant Property Prediction Error
'Purdue University (bepress)', 2014Co-Authors: Huang Long, Aute Vikrant, Radermacher ReinhardAbstract:Numerical simulation is extensively used in heat exchanger design and performance evaluation. While evaluating potential working fluids, pure fluids and fluid mixtures with different component combinations and fractions are compared based on simulation results. Two of the challenges while conducting such studies are the uncertainties of Refrigerant properties and the applicability of empirical heat transfer and pressure drop correlations. Pure Refrigerant Property uncertainties are associated with experimental testing technique. The uncertainties of Refrigerant mixtures are significantly higher when mixing rules are applied due the lack of measured data. Most of the empirical correlations are developed for certain Refrigerants with a limited range of applicability of fluid states and tube geometry. Therefore, it is essential to understand the uncertainties in heat transfer coefficient and pressure drop calculations with different fluids. This paper presents a sensitivity analysis of heat transfer and pressure drop correlations for both in-tube condensation and evaporation cases. Multiple Refrigerant such as R1234yf, R1234ze(E), R134a, R32, R410A, R445A, D2Y60 and L41a are analyzed based on commonly used heat transfer and pressure drop correlations from the literature. The parameters of the analysis are the thermodynamic and transport properties of the Refrigerants. This study should be helpful to researchers and engineers in correlation selection during heat exchanger simulation and in understanding the potential prediction uncertainties while evaluating new fluids
-
Modelica-based Heat Pump Model for Transient and Steady-State Simulation Using Low-GWP Refrigerants
'Purdue University (bepress)', 2014Co-Authors: Ling Jiazhen, Qiao Hongtao, Aute Vikrant, Alabdulkarem Abdullah, Radermacher ReinhardAbstract:Due to the relatively high global warming potential (GWP) value of R410A, much effort has been devoted to the exploration of potential Refrigerants to replace R410A in the heat pump applications. Those studies involving natural Refrigerants, which are of zero or single-digit GWP values, have not yet demonstrated the readiness for the substitution because of various reasons such as low cycle efficiency, toxicity and flammability. Henceforward, some synthetic Refrigerants whose GWP values are significantly lower than R410A such as R32 and some R32-based blends such as D2Y60, are getting more attention. To evaluate the transient performance of those low-GWP Refrigerants, a Modelica-based heat pump model is developed to simulate a heat pump cycle during both steady state operations and transient operations. The model includes an efficiency-based compressor model, two segmented heat exchanger models, a control volume-based valve model and segmented pipe models. The heat exchanger model is capable of simulating multi-bank multi-circuit tube-fin heat exchangers with an arbitrary number of segments. The pipe model is developed based on the segmented heat exchanger model, and its implementation provides for better charge prediction compared to single lump model. In order to speed up the simulations, accelerated Refrigerant Property routines were developed for R32 based on REFPROP. System-level steady-state and transient simulations for several alternative low-GWP working fluids, R32 and D2Y60, are conducted. The simulation results are compared with the published experimental data obtained from the Alternative Refrigerant Evaluation Program (AREP). The data includes steady-state operation data based on ASHRAE A, B and C tests, and transient data from ASHRAE D cyclic operation test. The validation of R32 and D2Y60 steady-state data shows a maximum deviation of 7.5% and an average deviation of 4%. The transient simulation well captures the dynamic performance of vapor compression cycle during start-up and shut-down
Daniel Nikovski - One of the best experts on this subject based on the ideXlab platform.
-
Fast Refrigerant Property Calculations
2012Co-Authors: C. R. Zhao, Y. Nikovski, Christopher R. Laughman, Yiming Zhao, Daniel NikovskiAbstract:An interpolation-based method for computing Refrigerant properties which can be used in simu-lations of vapor-compression air-conditioning equipment is presented. This method uses bicubic functions to interpolate between samples of the Helmholtz energy surface as a function of tem-perature and density. Three beneficial characteristics of this method are discussed: speed, accu-racy, and consistency, as well as a means for using a variety of different independent variables are also presented. The implementation of this method is discussed, and experimental results for Property calculations for Refrigerant R-134a are presented which compare favorably to standard Newton-based equation of state methods
-
fast Refrigerant Property calculations using interpolation based methods
2012Co-Authors: Christopher R. Laughman, Yiming Zhao, Daniel NikovskiAbstract:An interpolation-based method for computing Refrigerant properties which can be used in simulations of vaporcompression air-conditioning equipment is presented. This method uses bicubic functions to interpolate between samples of the Helmholtz energy surface as a function of temperature and density. Three beneficial characteristics of this method are discussed: speed, accuracy, and consistency, as well as a means for using a variety of different independent variables are also presented. The implementation of this method is discussed, and experimental results for Property calculations for Refrigerant R-134a are prese nted which compare favorably to standard Newton-based equation of state methods.