Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels

Mikielewicz, Dariusz; Wajs, Jan; Andrzejczyk, Rafał; Klugmann, Michał

doi:10.1016/j.ijrefrig.2016.03.005

Cited by 24 publications

(23 citation statements)

References 15 publications

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“…Selection of the minichannel heat exchangers geometry results from authors' long-standing experience [40][41][42] of investigations in minichannels with various aspects, ranging from single phase to two-phase flows.…”

Section: Methodsmentioning

confidence: 99%

Selected studies of flow maldistribution in a minichannel plate heat exchanger

Dąbrowski¹,

Klugmann²,

Mikielewicz³

2017

Archives of Thermodynamics

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Analysis of the state of-the-art in research of minichannel heat exchangers, especially on the topic of flow maldistribution in multiple channels, has been accomplished. Studies on minichannel plate heat exchanger with 51 parallel minichannels with four hydraulic diameters, i.e., 461 µm, 574 µm, 667 µm, and 750 µm have been presented. Flow at the instance of filling the microchannel with water at low flow rates has been visualized. The pressure drop characteristics for single minichannel plate have been presented along with the channels blockage, which occurred in several cases. The impact of the mass flow rate and channels' cross-section dimensions on the flow maldistribution were illustrated.

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Section: Methodsmentioning

confidence: 99%

Selected studies of flow maldistribution in a minichannel plate heat exchanger

Dąbrowski¹,

Klugmann²,

Mikielewicz³

2017

Archives of Thermodynamics

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“…In calculations presented below the sensitivity of the developed model to the selection of the two-phase flow multiplier has also been examined. For that purpose four models of two-phase flow multipliers were introduced into equation 1, namely modified correlation due to Friedel [10], Tran [11], Muller-Steinhagen and Heck [9], and the latter taking into account of the non-adiabatic effect [12]. Relationships, which describe the two-phase multiplier using during this analysis have been shown in Table 1.…”

Section: The Modellingmentioning

confidence: 99%

The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels

Mikielewicz

Jakubowska

2018

E3S Web Conf.

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In the paper presented are the results of the study on the effect of reduced pressure on flow boiling heat transfer data in minichannels as well as conventional ones. That effect renders that most of heat transfer correlations fail to return appropriate results of predictions. Mostly they have been developed for the reduced pressures from the range 0.1-0.3. The special correction has been postulated to the in-house model of flow boiling and condensation which modifies the two-phase flow multiplier as well as the temperature gradient in pool boiling. Four two-phase flow multiplier models were tested for this purpose, i.e. due to Friedel, Tran, Müller-Steinhagen and Heck and finally its in-house modification for applicability to minichannels. The model has been tested against a large selection of experimental data collected from various researchers to investigate the sensitivity of the in-house developed model. The collected experimental data came from various studies from literature and were conducted for the full range of quality variation and a wide range of mass velocity and saturation temperatures. In the work are presented the results of calculations obtained using the in-house developed semi empirical model on selected experimental flow boiling data related to carbon dioxide.

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“…Many modern methods of analyses [58][59][60] are aimed to increase the effect gained due to ambient air processing, in particular, to reduce energy and fuel consumption. Some of such methods include calculation of cooling degree-hours (CDH) [14,61] and modified versions [62][63][64] to match current cooling duties according to actual climatic conditions as well as thermal demand management (TDM) [65,66] based on different criteria [67,68] to save energy in building conditioning, engine intake air cooling and combined cooling, heat and power.…”

Section: Introductionmentioning

confidence: 99%

Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

et al. 2020

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The efficiency of cooling ambient air at the inlet of gas turbines in temperate climatic conditions was analyzed and reserves for its enhancing through deep cooling were revealed. A method of logical analysis of the actual operation efficiency of turbine intake air cooling systems in real varying environment, supplemented by the simplest numerical simulation was used to synthesize new solutions. As a result, a novel trend in engine intake air cooling to 7 or 10 °C in temperate climatic conditions by two-stage cooling in chillers of combined type, providing an annual fuel saving of practically 50%, surpasses its value gained due to traditional air cooling to about 15 °C in absorption lithium-bromide chiller of a simple cycle, and is proposed. On analyzing the actual efficiency of turbine intake air cooling system, the current changes in thermal loads on the system in response to varying ambient air parameters were taken into account and annual fuel reduction was considered to be a primary criterion, as an example. The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

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Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels

Cited by 24 publications

References 15 publications

Selected studies of flow maldistribution in a minichannel plate heat exchanger

Selected studies of flow maldistribution in a minichannel plate heat exchanger

The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels

Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

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