RICERCA ITALIANA     

Innovative techniques for the enhancement of forced convection

Università degli Studi di Parma

Abstract

Although convective heat transfer fundamentals are well known as a result of the work done by many researchers in the last century, some applications in many both civil and industrial fields still require research work. Heat transfer applications which include convection enhancement techniques certainly deserve further research efforts.

The here presented two year research project is focused on this argument and aims to coordinate the efforts of a part of the scientific national community within the research in heat transfer towards the deepening of both theoretical and applicative knowledge on the mechanisms responsible for the intensification effects in convection heat and mass transfer.

Although the scientific literature on both passive and active heat transfer enhancement techniques is wide and variegated and although it is well-known the important benefits, in terms of cost and size reduction and of energy saving correlated to their usage, the application of these technologies in some industrial fields is affected by a certain delay, or in any case requires the development of some optimization procedures. These difficulties are in part related to the gap, which the researchers involved in the present project hope indirectly to fill, persisting in Italy between the industrial and the academic research fields.

The researches suggested by the five local units are integrated within the global project as complementary activities >>>

Principal Investigator

Sara Rainieri Università degli Studi di PARMA

Research Objectives

The here proposed research aims to the deepening of both theoretical and applicative knowledge on the techniques for the intensification of forced convection.
The proposers intend in this way to provide useful tools to help the Italian industry to stay competitive on the market of heat exchangers, in particular of both plate-and-fin and tube-and-fin compact heat exchangers.
In fact, all the five research units have directly or indirectly some connections with manufacturers involved in this field, therefore the here proposed project will have a great effect on the national industry in relation to the ability of designing and innovating the heat transfer equipments.
Compact heat exchangers are a mature product, and the Italian industry must come out with innovative applications to stay ahead of foreign producers. Users are particularly sensible to the ratio cost/ performances and it is clear that the Italian industry must essentially compete on the performances front. Our research proposal thus include a series of studies on high efficiency fins, capable of considerably increasing the heat transfer on the gas side (the traditional weak spot of compact heat exchangers).
The enhancement of convection allows, above all, to produce more compact and, consequently, less expensive heat exchangers.
Furthermore, the development of convection enhancement techniques is nowadays a even more strict demand in the field of refrigeration and air-conditioning >>>

First Results

The primary results expected by the present research are analitically described in relation to the role of each research units in section 14.
On the whole the here presented research project aims to coordinate the efforts of a part of the scientific national community within the research in heat transfer towards the deepening of both theoretical and applicative knowledge on the mechanisms responsible for the intensification effects in convection heat and mass transfer.
The primary objective is to fill some of the scientific knowldedge gaps and to deepen still open problems in the field of techniques aimed to the intensification, both by means of passive and active systems, of convection transfer.
The project, scheduled into two yearly stages, aims to bring methodological and technological innovations into the industrial field relevant for the present project.
One of the expected result is the honing of both experimental and numerical methodologies, aimed to the modelling and comprehension of the physical phenomena related to the use of convection ehnancement techniques, both in mono-phase and in surface condensation conditions.
The research team intends also to apply the investigation methodology to situations of industrial relevance.
The expected results will provide useful tools to the Italian industry in order to help it to stay competitive on the market of heat exchangers, in particular of compact heat exchangers both of the >>>

Timescale

24 months

National and international background

An examination of both the national and international scientific literature in the field of heat transfer, reveals the relevance and novelty of the argument of both passive and active techniques aimed to the intensification of the convection energy and mass transfer.
Studies in the past, however, have concerned, essentially, heat transfer in the steady state and the use of passive traditional systems for the enhancement of convection, primarily to be applied to mono-phase conditions. The most important and innovative technological developments, proposed in this research, will deal with:
-both experimental and numerical techniques aimed to the assessment of the performance of enhanced heat transfer surfaces in simultaneous forced convection transport of energy and mass, also by considering the unsteady operating regime;
-study of heat dissipators which adopt both passive and active systems for the intensification of the convection mechanism.

The scientific foundation of this studies is given by the very large number of contributions to the technical literature published in the past, also by researchers from our group, and by the knowledge of the international technical literature acquired by them in the course of their researches. The considerations outlined in the following and the vast bibliography reported below and included in each local project support these statements.

Passive convection enhancement techniques are based >>>