scholarly journals Experimental Study on Leak Flow Rate and Inner Flow Characteristics of Plate Heat Exchangers with Pin-hole Location and Mass Flux

2016 ◽  
Vol 28 (5) ◽  
pp. 171-177
Author(s):  
Kang Sub Song ◽  
Chanhyun Baek ◽  
Sung Woo Kim ◽  
Yongchan Kim
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Mass Flux ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Plate Heat

EXPERIMENTAL STUDY OF ENERGY DISSIPATION IN A SINGLE STEP CONDITION OVER A BROAD CRESTED WEIR

2021 ◽  
Vol 5 (2) ◽  
pp. 155-165
Author(s):  
Bashir Tanimu ◽  
Aliyu Bamaiyi Usman ◽  
Al-Amin Danladi Bello ◽  
Sulaiman Jamilu Abdullahi
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Flow Rate ◽  
Research Study ◽  
Flow Characteristics ◽  
Single Step ◽  
Transition Flow ◽  
Experimental Performance ◽  
Empirical Relations ◽  
Model Equations

This research study the experimental performance of broad-crested weir with single-step by introducing U/S and D/S round-nose and  analysing the parameters that have effect on the shape of the step and their effects on the flow characteristics and energy dissipation (E%) downstream (D/S) of the weir. Furthermore, empirical relations for E% and flow rate due to the influencing factors were derived. The results showed that the weir model with  = 1.000 gives a higher E% in comparison with other weir models. Flow regimes were observed i.e nappe flow for small discharges, transition flow for intermediate discharges and skimming flow for higher discharges. Two model equations were obtained, the first to dteremine the flow rate over the weir models and the second relation to estimate E% in terms of, and Froude number. The model () can be used in the design of prototype weirs in terms of energy dissipation

Performance of Plate Heat Exchangers Used as Refrigerant Liquid-Overfeed Evaporators

2010 ◽  
Author(s):  
Jianchang Huang ◽  
Thomas J. Sheer ◽  
Michael Bailey-McEwan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Mass Flux ◽  
Heat Exchangers ◽  
Strong Dependence ◽  
Nucleate Boiling ◽  
Small Range ◽  
Plate Heat ◽  
System Pressure

The heat transfer and pressure drop characteristics of plate heat exchangers were measured, when used as refrigerant liquid over-feed evaporators. The three units all had 24 plates but with different chevron-angle combinations of 28°/28°, 28°/60°, and 60°/60°. R134a flowing upwards was used as the refrigerant, in a counter-current arrangement with water flowing on the other side. Heat transfer and pressure drop measurements were made over a range of mass flux, heat flux and corresponding outlet vapour fractions. The effect of system pressure on the evaporator performance was not evaluated due to the small range of evaporating temperature. Experimental data were reduced to obtain the refrigerant-side heat transfer coefficient and frictional pressure drop. The results for heat transfer showed a strong dependence on heat flux and weak dependence on mass flux and vapour fraction. Furthermore, the chevron angle had a small influence on heat transfer but a large influence on frictional pressure drops. Along with observations that were obtained previously on large ammonia and R12 plate evaporators, it is concluded that the dominating heat transfer mechanism in this type of evaporator is nucleate-boiling rather than forced convection. For the two-phase friction factor, various established methods were evaluated; the homogeneous treatment gives good agreement.

An Experimental Study on the Influence of Flow Maldistribution on the Pressure Drop Across a Plate Heat Exchanger

2004 ◽  
Vol 126 (4) ◽  
pp. 680-691 ◽  
Author(s):  
B. Prabhakara Rao ◽  
Sarit K. Das
Keyword(s):  
Experimental Study ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Plate Heat Exchanger ◽  
Operating Conditions ◽  
Plate Heat ◽  
General Flow ◽  
Proper Design ◽  
Flow Maldistribution

A detailed experimental study on flow maldistribution from port to channel of a plate heat exchanger is presented. In general, flow maldistribution brings about an increase in pressure drop across the heat exchanger. This increase is found to depend on flow rate, number of channels and port size. Experiments show that analytical predictions of pressure drop including maldistribution effect are quite accurate for practical purposes. The results indicate that under identical conditions, maldistribution is more severe in Z-type plate heat exchanger compared to U type. Experiments are also carried out under non-isothermal realistic operating conditions, which show increased flow maldistribution at elevated temperature. Finally predictions are made for industrial plate heat exchangers, which show the limitation of adding additional plates beyond a certain limit. An insight to the physical aspects of maldistribution and its possible reduction through proper design strategy is also indicated.

scholarly journals Calculating the optimal physical size of an industrial plate recuperator

2020 ◽  
pp. 95-101
Author(s):  
Tauger Vitalii ◽  
◽  
Minin Ivan ◽  
Adas Vitalii ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Aerodynamic Resistance ◽  
Physical Size ◽  
Plate Heat ◽  
Flow Part ◽  
Excessive Load ◽  
Reduced Power Consumption

Introduction. The wide spread of plate heat exchangers in various fields of technology is due to the simplicity of their design and a variety of layout schemes. An area where their use is very promising is heat recovery. The effect of an air heat exchanger-recuperator consists in heating the incoming flow with the heat of the outgoing flow and is expressed in drastically reduced power consumption, which would otherwise be spent on heating. Research methodology. The object of research is a recuperator designed to heat the air entering the production room in winter. Resistance to air flow is a significant disadvantage of the plate heat exchange. The aerodynamic resistance reduces the flow rate, therefore, leads to a decrease in the flow rate of air passing through the recuperator, so the required flow rate is ensured by special fan installations. The task of designing a recuperator is to minimize the size of the flow part and prevent excessive load on the fan unit. Calculation with the use of the recuperatorТs mathematical model is applied in the research. Results. In the course of the research, a mathematical model of the recuperator has been developed, which includes a condition for limiting the pressure loss by an acceptable value. Ratios have been obtained for determining the optimal duct width between the plates, plates height, length and number. Conclusion. A simplified mathematical model has been proposed to estimate the dimensions of the flow part. The reliability of the simplified model has been confirmed by numerical calculation.

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